Ground strike

Investigation summary

What happened

On 25 June 2024, a British Aerospace BAe 146‑300, registered VH‑SAJ, was being operated by ASL Airlines Australia on a freight flight from Sydney, New South Wales, to Brisbane, Queensland. On board the aircraft were the captain and first officer.

While on descent into Brisbane, the meteorological conditions worsened with visibility reducing to about 1,000 m in fog. The crew conducted an instrument approach for runway 19L, using the autopilot, and visually identified the high intensity approach lighting at about 220 ft. The first officer disconnected the autopilot at about 110 ft and made control inputs that resulted in an increasing aircraft pitch attitude with decreasing airspeed. The aircraft touched down with a high pitch angle and a vertical acceleration of about 2.4 g. The tail of the aircraft struck the runway, resulting in damage to the tail strike indicator and surrounding panels.

What the ATSB found

The ATSB’s investigation identified that the first officer likely became disoriented after disconnecting the autopilot and lost situation awareness. Consequently, they did not identify the increasing aircraft pitch attitude, decreasing airspeed, or low power setting and did not correct the resulting sink rate prior to touchdown. The captain prevented further rearward input by the first officer during the flare by placing their hand on the control column, likely reducing the severity of the tail strike.

It was also found that during the approach the captain became preoccupied with the remaining fuel on board and this likely limited their capacity to monitor other factors such as the first officer’s ability to undertake the approach and the undesired state of the aircraft during the flare. The ATSB also identified that the captain’s actions and communications during the approach likely increased the pressure on the first officer to commit to the landing. 

Prior to joining the operator, the captain had predominantly flown single pilot operations in non‑jet aircraft. They had been promoted to the position of captain early, which resulted in a missed opportunity to gain valuable experience within a multi‑crew environment prior to commencing in the role. This limited multi‑crew experience likely reduced the captain’s capacity to include the first officer in the decision-making process during the approach or make an authoritative decision to assume the pilot flying role.

The ATSB identified that both the captain and first officer had been appointed to their respective positions despite not meeting the ASL Airlines Australia minimum experience requirements. This occurred without additional controls in place to manage the risk of lower experienced pilots and resulted in a reduction in the intended experience level on the flight deck for the incident flight. 

What has been done as a result

Following an internal investigation by ASL Airlines Australia the following safety actions have been taken:

• The upgrade or fleet transfer requirement of a minimum of 500 hours on a company type, or as deemed appropriate by the Director of Flight Operations contained in the operations manual was amended to a minimum of 500 hours on a company type, or similar type in terms of maximum take‑off weight as deemed appropriate by the Director of Flight Operations, Head of Training and Checking and Director of Safety.
• Inexperienced flight crew that have been checked to line will not have their inexperienced status removed without a review of the candidate’s progress by the Director of Flying Operations or Head of Training and Checking.
• The Planned Supervised Line Flying sectors for Captains – No Jet Experience listed in the OM‑D – Training and Checking Manual have been increased from 30 to 36 sectors.
• Supervised Line Flying sectors for First Officers without previous jet experience has been increased from 30 to 36 sectors.
• The Fleet Training Manager will review a candidate’s experience at the planning stage, and may elect to plan less, or more sectors, dependent upon the candidate’s progress.
• Additional systems to track pilots with inexperienced status to avoid inadvertent rostering of inexperienced crew together.
• The operator’s internal review identified an inconsistency between the operator’s standard operating procedures and the manufacturer’s recommendation with regard to which pilot (the pilot flying or the pilot monitoring) was to make an ‘attitude’ call when the aircraft pitch angle approaching landing increased above 5°.
• The BAe 146 standard operating procedures manual has been updated and aligns with the manufacturer’s recommendation.
• The operator’s internal review identified there was no policy stipulating that the captain must perform the landing when the weather conditions are below certain weather criteria.
• A policy has been developed and incorporated into the operations manual that states the captain must conduct the approach and landing with visibility within 1,000 m and cloud within 100 ft of the minima unless the pilot in command is a company approved training or check pilot.

Safety message

Current shortages of aviation professionals, including pilots, have resulted in the need for operators to employ crew with less experience than has previously been expected. Operators are encouraged to review the employment and promotion processes for inexperienced crew, ensuring that additional training programs, or limitations on inexperienced crew and the pairing of less experienced crew during rostering are considered.

The occurrence

Overview

On 25 June 2024, a British Aerospace BAe 146‑300, registered VH‑SAJ, was being operated by ASL Airlines Australia on a freight flight[1] from Sydney, New South Wales, to Brisbane, Queensland. There were 2 flight crew on board. The captain was pilot monitoring, and the first officer (FO) was pilot flying. [2]

The aircraft departed Sydney at about 0415 with first light occurring at Brisbane at 0613. The forecast visibility for arrival at Brisbane was 10 km. While on descent to Brisbane, the meteorological conditions worsened with visibility reducing to about 1,000 m in fog. The crew conducted an instrument landing system (ILS) approach for runway 19L,[3] using the autopilot, and visually identified the high intensity approach lighting at about 220 ft. 

The FO disconnected the autopilot at about 110 ft and made control inputs that resulted in an increasing aircraft pitch attitude with decreasing airspeed. The aircraft touched down with a high pitch angle and a vertical acceleration of about 2.4 g. The tail of the aircraft struck the runway, resulting in damage to the tail strike indicator and surrounding panels.

Cruise and descent

At about 0457, while the aircraft was in cruise at flight level[4] (FL) 270 and approximately 350 km to the south of Brisbane, air traffic control (ATC) advised the crew to expect runway 19L for their arrival.

At about 0505, cockpit voice recorder (CVR) data indicated that the captain obtained the automatic terminal information service (ATIS)[5] for Brisbane Airport. The meteorological conditions at that time were reported as a wind from 190° at 8 kt, visibility greater than 10 km with showers in the area, cloud few[6] at 500 ft, scattered[7] at 3,000 ft, and a temperature of 14°C (see Meteorological information). The captain then completed the take‑off and landing data (TOLD) card. This included calculated figures for fuel overhead the destination (Brisbane) of 2,400 kg and a minimum divert fuel of 1,700 kg.

The crew then conducted a briefing for the arrival into Brisbane and the ILS approach for runway 19L (see Airport information).

During the briefing, the FO noted the minima for the approach including a decision altitude (DA)[8] of 220 ft and visibility of 800 m, stating that conditions in Brisbane at the time were ‘showers and wet’.

At 0513, ATC advised the crew that the ATIS had been updated, and the cloud was now few at 200 ft, scattered at 3,000 ft and the temperature was 13°C. At 0519, when the aircraft was about 125 km south of Brisbane, ATC issued the crew with a clearance to descend to FL 130. A short time later, the captain commented on the cloud at 200 ft to the FO. The FO stated that they had 20 minutes of fuel, which was enough for a second approach if needed. The captain replied with ‘yeah, then we’re landing anyway’. The crew then completed the approach checklist.

The captain later advised that they believed their comment was a standard operational comment based on fuel limits.

Figure 1: VH-SAJ flight track for arrival to Brisbane Airport

Source: Google Earth, annotated by the ATSB. *Flight was conducted in darkness

At 0521, the crew commenced the descent to FL 130. At 0525, ATC issued the crew with a further clearance to descend to 9,000 ft. A short time later, the crew were advised by ATC to expect the ILS approach for runway 19L.

At 0526, when the aircraft was about 67 km south-east of Brisbane, ATC advised the crew of low cloud south of the airport that was moving north and that they may be required to delay their arrival. On receipt of the meteorological information from ATC, the captain commented to the FO that they had ‘no fuel’. The FO proposed that they had sufficient fuel to complete 2 approaches, declare minimum fuel, and complete a third approach. The captain commented that they would just land from the second approach as they would ‘rather be on the ground’, expressing concerns about the paperwork involved. 

Over the following 2 minutes, the captain and the FO continued to discuss the options for the approach with the captain stating that, given the fuel state, conducting a go‑around may result in a worse scenario as they expected the meteorological conditions at Brisbane to worsen. The crew did not discuss options for a diversion if they were required to undertake a go‑around due to the meteorological conditions. The closest suitable airport was the Gold Coast (see Gold Coast Airport meteorological conditions during flight). 

At 0529, ATC advised that the visibility had reduced to 1,000 m in fog, with a cloud base of 200 ft and that low visibility procedures were in force with the high-intensity approach and runway lighting operating.

At 0530 the crew discussed the changing meteorological conditions. During this discussion, the captain stated that the conditions would only get worse and if they could see the high‑intensity approach lighting, then they were going to land. The FO agreed and stated that the captain should ‘call it when you see it’.

At about 0531, the aircraft passed through 11,000 ft and, a short time later, the crew initiated the additional approach checks. At 0533, the crew were cleared to continue the descent to 4,000 ft.

There were 3 aircraft ahead of VH-SAJ on approach to land on runway 19L at Brisbane Airport. At about 0532, the first of the 3 preceding aircraft landed and reported becoming visual with the runway at the minima.

Final approach

At 0534, ATC provided a clearance for the crew to undertake the ILS approach for runway 19L.

At 0536, the second aircraft in the sequence ahead of VH‑SAJ conducted a go‑around, later reporting to the ATSB that the combination of reduced visibility and low cloud prevented them from landing. At 0537, the captain of the third aircraft in the sequence declared to ATC, ‘should we, we will require an immediate diversion to the Gold Coast’. However, the third aircraft landed successfully.

The CVR indicated on hearing the transmission from the aircraft advising a go‑around, the captain stated ‘we haven't got the fuel for this’. The captain later stated that their comment was over concern should multiple go‑arounds be required.

At about 0539, VH-SAJ became established on the ILS for runway 19L. At about 0540, approximately 4 minutes prior to landing, the captain stated to the FO that they did not have enough fuel to divert to the Gold Coast. The FO queried if it was possible to recalculate if there was sufficient fuel to conduct the diversion to the Gold Coast, to which the captain responded ‘not now on final, but let's try and get in’. 

The captain later stated that they believed that it was not appropriate on final approach to calculate fuel for a diversion. 

At 0541:28, the crew completed the landing checklist.

Landing

At 0541:45, the crew were provided with a landing clearance from ATC (Figure 2) and were advised that the runway visual range[9] was 1,200 m at the touchdown zone, 1,200 m at the runway mid‑point and 1,800 m at the end point of the runway. 

Figure 2: VH-SAJ final approach to Brisbane Airport

Source: Google Earth, annotated by the ATSB. *Flight was conducted in darkness

At 0542:05, the captain instructed the FO to leave the autopilot connected until the aircraft reached 220 ft (the BAe 146‑300 minimum autopilot disconnect height is 60 ft). The captain later recalled to the ATSB that they did so to keep the aircraft on an accurate approach to the runway. The FO confirmed they would leave the autopilot engaged but also stated they would disconnect it should they require a go-around. In response, the captain stated ‘we don't want to go around. It’s gonna be a world of hurt’. The FO responded ‘but if we can't see, then we're gonna have to’. 

The captain later responded after reviewing the draft report that their comment was over concern that a go‑around may lead to a more dangerous fuel critical situation and recalled at the time they considered similar occurrences that had occurred to other operators. 

At 0542:40, the aircraft descended through 1,000 ft and was about 7 km from the runway threshold. At the same time, the captain advised the FO that the aircraft was stable, with the missed approach altitude set and armed.

At 0543:05 and about 600 ft, the captain announced they were visual with the high intensity approach lighting, the FO responded that they could also see the lighting, however ‘not super clearly’. At 0543:31 and about 350 ft, the captain instructed the FO to increase engine power.

At 0543:45, the aircraft reached the DA and the FO announced they could see the high intensity approach lighting. Four seconds later, the captain announced ‘there’s the runway’. The captain later recalled to the ATSB that they had more visibility than they had expected.

At 0543:57 the captain instructed the FO to disconnect the autopilot, which occurred at about 110 ft and an airspeed of about 128 kt. The airbrake[10] was extended and fully deployed as the aircraft passed 80 ft. Several pitch adjustments were made by the FO after the autopilot was disconnected. The FO later described that from the DA until landing, their workload increased ‘to a 9 or 10 out of 10’, they became ‘overwhelmed’ and that their scan pattern had broken down. The CVR indicated that neither the FO nor the captain commented on workload during the approach.

At 0544:01, both the captain and the FO announced becoming visual with the PAPI lights.[11] The FO later recalled they could make out the runway edge lighting, however could not see the touchdown point.

Just prior to touchdown, the captain instructed the FO ‘don’t come back too far’. The captain later recalled to the ATSB that the FO had levelled the aircraft shortly after disconnecting the autopilot and began to flare[12] too early. They recalled that the aircraft became high, slowed and then developed a high sink rate. From previous experiences they anticipated that the FO would attempt to pitch the aircraft up to arrest the sink rate. As a result, the captain placed their hand on the control column to prevent the FO from pulling back too far without verbalising their intention (see Operational policy and procedures). The FO also later recalled feeling the captain’s pressure on the control to prevent further rearward input. 

The captain recalled to the ATSB that it was a common reaction for less experienced pilots to pull back and increase the pitch when the aircraft experienced a drop, and that this is discussed during their command training.

At 0544:11 the aircraft main wheels contacted the runway. The onboard flight data recorder captured a vertical acceleration of 2.4 g at initial touchdown, an aircraft pitch attitude of about 5.3°, and an airspeed of 105 kt (see Recorded information). 

The crew were unaware of the tail strike until the damage was discovered on the post‑flight aircraft inspection. The tail contact with the runway damaged the tail strike indicator and surrounding fuselage skin panels (Figure 3). 

Figure 3: VH-SAJ damage to tail strike indicator and surrounding panels

Source: ATSB

Context

Personnel information

Captain

Experience

The captain held an air transport pilot licence (aeroplane), issued in October 2017, and a valid class 1 aviation medical certificate. At the time of the incident, the captain had about 7,500 hours total aeronautical experience, of which about 5,400 hours was multi‑engine command. They had a total of 411 hours on the BAe 146, which included 198 hours as captain. The BAe 146 was the captain’s first jet aircraft rating, having previously flown smaller twin turboprop aircraft mostly in single pilot operations before commencing employment with the operator.

Operator training

The captain joined ASL Airlines Australia in November 2022 as a first officer. They completed their type rating on the BAe 146 aircraft in early 2023 and they were checked to line as a first officer in July 2023. In October 2023, they were assessed and recommended to undertake command training. At that time, their total BAe 146 time was 155 hours.

Their command training commenced in November 2023 and involved simulator training and command checks. During this training, the captain’s initial operator proficiency check (OPC) was assessed as unsatisfactory due to a breakdown in situation awareness during an instrument approach. Additional simulator training was provided, and the captain passed their OPC on 23 November 2023. The captain’s subsequent command simulator training was also assessed as unsatisfactory and was required to be retaken. 

On 4 December 2023, the captain commenced supervised line flying sectors. The captain completed 19 sectors before being recommended to undertake their check to line on 19 December 2023. The captain’s check to line was assessed as unsatisfactory after the first sector. The captain was provided with additional simulator and ground school training support. The captain completed a further 8 supervised line flying sectors before being recommended to retake their line check. The captain successfully completed their line check on 15 February 2024.

The captain’s command training consisted of 31 sectors and 58 hours of flying.

First officer

Experience

The first officer (FO) held a commercial pilot licence (aeroplane), issued in March 2020, and a valid class 1 aviation medical certificate. The FO’s total aeronautical experience was about 1,090 hours, including about 113 hours as an FO on the BAe 146. Prior to their employment with the operator, the FO had flown for a general aviation operator, flying mostly smaller, single-engine aircraft and operating under visual flight rules.  

Operator training

The FO joined ASL Airlines Australia in January 2024. They completed their type rating on the BAe 146 aircraft on 4 March 2024. They undertook 2 simulator sessions before successfully completing their OPC on 28 March 2024. 

The FO commenced supervised line flying sectors in April 2024. The FO was assessed as achieving below the required standard in several areas including situation awareness, approach and landing. The FO undertook a simulator session on 8 May 2024 and an additional 16 supervised line flying sectors. The FO recalled that their simulator training included low visibility operations, but they had not previously landed an aircraft in foggy conditions.  

On 28 May 2024 they were assessed as not proficient during their check to line. The FO was reassessed on 29 May 2024, 28 days prior to the incident and successfully completed their check to line.

The FO’s training consisted of 51 sectors and 90 hours of flying. 

Fatigue

The ATSB considered the role of crew performance due to fatigue and found that, from the available evidence, fatigue was unlikely to have contributed to the incident (see Fatigue).

Aircraft information

General information

The BAe 146 (Figure 4) is a high‑wing cantilever monoplane with a T‑tail. It is powered by 4 Avco Lycoming ALF 502 turbofan engines mounted on pylons underneath the wings and had retractable tricycle landing gear. 

The aircraft, serial number E3150, was a BAe 146‑300 series aircraft manufactured in 1989 and configured for air freight operations. It was first registered in Australia as VH‑SAJ on 24 October 2019. The last periodic inspection was completed on 12 June 2024 and on the day of the occurrence, the aircraft had accumulated 34,746 hours total time in service. 

Figure 4: VH-SAJ BAe 146-300

Source: Jet photos, Cameron Roberts

Aircraft operator

At the time of the incident, ASL Airlines Australia (previously Pionair) held an air operator’s certificate issued by the Civil Aviation Safety Authority (CASA) on 14 May 2020 and valid until 1 December 2027, that authorised air transport in larger aeroplanes (CASR Part 121). ASL Airlines Australia operated a mixed fleet of aircraft that comprised 6 BAe 146s and 1 Boeing 737 aircraft, conducting mostly domestic air freight operations. 

Airport information

Brisbane Airport

Brisbane Airport has 2 runways oriented 10°/190° magnetic (01L/19R and 01R/19L). At the time of the incident, aircraft departures and arrivals were taking place using runway 19L. The airport has a category 1 instrument landing system (ILS) on both runways. This landing system, combined with a 100% LED[13] category 1 lighting system,[14] including stop bar lighting, enables operations during low visibility events like fog.

Instrument approach

The crew of VH-SAJ were flying an ILS approach for runway 19L. The minima for the approach included a decision altitude8 of 220 ft, visibility of 800 m, and a runway visual range of 550 m (Figure 5).

Figure 5: Brisbane ILS runway 19L approach chart with landing minimums (blue box)

Source: Airservices Australia, annotated by the ATSB

Meteorological information

Predeparture briefing

The captain and FO were issued with a flight briefing package at 0057 that morning, which included the current terminal aerodrome forecast (TAF)[15] that was valid between 0000 on 25 June and 0400 on 26 June for Brisbane Airport. 

At the time the flight briefing was issued, the TAF for Brisbane indicated:

• wind 210° at about 4 kt
• visibility greater than 10 km
• cloud few at 2,000 ft and broken[16] at 4,000 ft
• active INTER[17] from 0000 through till 0400 for visibility of 3,000 m in showers of moderate rain and broken cloud at 1,500 ft. 

Prior to their departure from Sydney, the crew checked the latest weather information for their arrival into Brisbane. The latest TAF had not extended the INTER period for showers beyond 0400.

Brisbane Airport meteorological conditions during flight

The aircraft departed Sydney Airport at 0415, one hour and 15 minutes after the scheduled departure time and had an estimated time of arrival in Brisbane at 0555. Over the period 0500 to 0525 the visibility at Brisbane Airport remained greater than 10 km. From 0525 to 0550 the visibility reduced from greater than 10 km to 660 m due to the formation of advected fog.[18] The recorded visibility at the time VH‑SAJ landed was 912 m (Figure 6). 

Figure 6: Brisbane Airport visibility 0445 to 0615 on 25 June 2024

Source: Bureau of Meteorology, annotated by the ATSB

Closed circuit television (CCTV) recorded from the Brisbane air traffic control tower captured a progressive reduction in visibility that was consistent with the recorded meteorological information (Figure 7). 

Figure 7: CCTV images from Brisbane Airport tower facing south

Source: Brisbane Airport Corporation, annotated by the ATSB

Gold Coast Airport meteorological conditions during flight

The closest alternate to Brisbane Airport was Gold Coast Airport which had a TAF issued at 0306 that contained an active TEMPO[19] for visibility of 4,000 m in showers of rain, with cloud scattered at 1,000 ft and broken at 2,000 ft. 

At 0530, the Gold Coast meteorological aerodrome report (METAR) indicated visibility greater than 10 km and lowest cloud base of few at 6,100 ft. The subsequent METAR, issued at 0600, indicated visibility was still greater than 10 km with the lowest cloud base being scattered at 3,600 ft. 

The Gold Coast Airport forecast was not issued to the crew as part of their flight briefing package and the crew did not obtain the Gold Coast Airport ATIS during the flight.

Recorded information

The aircraft was fitted with an L3[20] F1000 flight data recorder and L3 FA2100 cockpit voice recorder. Both units were transferred to the ATSB technical facilities in Canberra, Australian Capital Territory, for download.

Recorded flight data during the approach phase indicated the aircraft was flown within the ASL Airlines Australia stabilised approach criteria. At a height of about 110 ft, approximately 13.5 seconds before the main gear touchdown, the data indicated the autopilot was disconnected. Immediately following the disconnection of the autopilot, over a period of 5 seconds, the aircraft pitch attitude increased from about −4.3° to about 0° (Figure 8). At the same time the aircraft speed reduced from about 128 kt to about 120 kt. The crew had calculated the aircraft landing reference speed (V_ref)[21] to be 115 kt and the aircraft approach speed (V_app)[22] to be 120 kt (V_ref + 5 kt). 

The airbrake was deployed at a height of 100 ft and was fully extended when the aircraft reached 80 ft. ASL Airlines Australia standard operating procedures manual for the BAe 146 advised that the airbrake should be deployed on final approach once the landing was assured.

Figure 8: Recorded flight data

Source: ATSB

At a height of about 65 ft, the aircraft decelerated through 117 kt with a pitch attitude of about −3.6° and an increasing rate of descent. Several further pitch attitude adjustments were recorded as the aircraft continued to descend.

At a height of about 30 ft, the pitch attitude decreased to about −2.3°, airspeed reduced to about 109 kt and the rate of descent increased. Shortly after, the pitch attitude increased to a maximum of about 5.3° coincident with main gear touchdown. The vertical acceleration at main gear touchdown was 2.4 g and the airspeed was 105 kt. The aircraft engine power throughout the landing sequence was about 37% N1[23] and there was no recorded increase in power prior to contact with the runway. About 4 seconds after the initial touchdown the main gear momentarily recorded a weight off wheels followed by a vertical acceleration of 1.7 g, indicating a possible bounce.

The aircraft manufacturer advised that a tail strike in a BAe 146‑300 would occur on a hard landing, when the main gear oleos[24] had fully compressed, at a pitch attitude of 6.9° or higher. The difference between the values provided by the manufacturer and the recorded data were likely due to a combination of the flight data recorder sampling rate for the pitch attitude parameter (4 times a second) and the overall system accuracy (+/− 1.34°).

Operational information

Flight plan

ASL Airlines Australia operations provided the flight plan as part of the flight briefing package. The flight would depart Sydney and climb to FL 270. The track would take the flight overhead Newcastle, Grafton, Lismore and the Gold Coast, before landing at Brisbane. The flight was scheduled to continue from Brisbane with a planned landing in Townsville before the crew would end their duty period in Cairns.

Fuel planning

On departure from Sydney, the onboard fuel load was recorded as 5,800 kg with a planned trip fuel of 3,332 kg, including taxi fuel. ASL Airlines Australia operations had planned the flight with an additional 30 minutes of holding fuel due to the forecast INTER, planned between midnight and 0400 in Brisbane, which was later cancelled. A delay due to an engine vibration warning light resulted in an additional fuel burn, however the crew determined that as the INTER had been removed, that they had sufficient fuel for the sector. After discussion with the engineering team, the warning light was deemed to be a faulty indicator and the aircraft cleared to depart.

The operator’s fuel policy required a fixed final reserve fuel of 30 minutes as well as an additional 15 minutes of holding fuel when no alternate was required. This was a provision for weather, GPS RAIM[25] outage, traffic, or beginning of daylight. A contingency fuel margin of 5% of the trip fuel was also required to compensate for unforeseen factors.

VH-SAJ landed in Brisbane with about 2,300 kg of fuel remaining, which equated to about 72 minutes of flight time that included the use of reserve fuel. The ATSB was advised that ASL Airlines Australia had undertaken an internal review of the flight and that this review determined that the aircraft had sufficient fuel to conduct a missed approach at Brisbane and then divert to the Gold Coast before having to utilise the final reserve fuel margin.

Weight and balance

The operator’s load and trim sheet records indicated the aircraft was within the weight and balance limitations for the intended flight.

Preflight briefing

At the beginning of the duty period, the operator’s policy was for flight crew to conduct a ‘big picture briefing’. This was an opportunity to discuss any significant factors that may affect the planned operation and to focus on underlying threats or unusual factors and to discuss any means of mitigating those threats. 

During the big picture briefing conducted prior to flight, the captain and FO recalled that they discussed that they had not previously flown together, and the captain communicated that they were open to receiving any criticisms or concerns regarding their operating practices. The captain recalled assuming that the FO was new to the position, but they were unaware of the FO’s previous flying experience and were also unaware they had not previously landed in low visibility conditions. 

Operational policy and procedures

Flight crew experience requirements

Legislative requirements to be qualified as pilot in command

Civil Aviation Safety Regulation (CASR) part 121.495 required the following pilot in command experience:

(1) A pilot is qualified as pilot in command for a flight of an aeroplane if:

(a) the pilot meets the minimum flying experience requirements specified, in accordance with subregulation (2), in the aeroplane operator’s exposition for the aeroplane; and 

(b) the pilot has successfully completed command training that complies with regulation 121.565 for the aeroplane operator and an aeroplane; and

(c) the pilot is:

(i) if the aeroplane is an Australian aircraft—authorised to pilot the aeroplane during the flight as pilot in command under Part 61; or

(ii) if the aeroplane is a foreign registered aircraft—authorised to pilot the aeroplane during the flight as pilot in command by the aeroplane’s State of registry.

(2) For the purposes of paragraph (1)(a), the aeroplane operator’s exposition must include minimum flying experience requirements for all aeroplanes operated by the operator for Part 121 operations.

Operator’s documented requirements

The ASL Airlines Australia operations manual (OM-A) version 5.5, which was current when the flight crew were checked to their positions, contained the minimum experience requirements to be met before an FO could be considered for promotion to the position of captain (pilot in command). The stated experience requirements were:

• meet all regulatory requirements

• minimum of 3000 hours aeroplane

• minimum of 500 hours on a company type, or as deemed appropriate by the GMFO [General manager of flying operations]

• minimum of 500 hours multi-engine PIC [pilot in command] or ICUS [in command under supervision]

• Australian ATPL [air transport pilot licence] or CPL [commercial pilot licence] with exam credit in all required examination subjects may be acceptable if the company is able to arrange/conduct an ATPL flight test as part of the upgrade training program.

The OM-A also contained the minimum experience required for the employment of a first officer. The stated experience requirements were:

• minimum total time of 1000 hours

• minimum of 500 hours in multi-engine aircraft

• a current Australian CPL [commercial pilot licence] or ATPL [air transport pilot licence]. 

The OM-A permitted the employment or promotion of crew below the prescribed minimum hours in ‘exceptional circumstances’, with the specific approval of the director of flight operations (DFO). It stated:

All crew seeking positions as pilots with Pionair are to comply with the Australian CASR Part 61 requirements with respect to licencing. Flight crew experience criteria for the various categories are as detailed below. These criteria may be varied, with the specific approval of the Director of Flight Operations to cater for exceptional circumstances.

There was no definition of what would be considered ‘exceptional circumstances’ within the OM-A.

Incident flight crew engagement

Neither the captain nor the FO met the documented minimum requirements to hold their assigned positions at the time of the occurrence.

The FO had about 106 hours of multi-engine experience at the time of their engagement with ASL Airlines Australia and about 219 hours of multi‑engine experience at the time of the incident. The OM-A minimum multi-engine experience requirement for the position was 500 hours.

The captain completed their command check to line in February 2024. At that time, they had accumulated about 213 hours on the BAe 146, of which 155 hours were as FO and an additional 58.7 hours in command under supervision as part of their command training course. At the time of the incident, they had accumulated about 411 hours total flying in the BAe 146 as FO and captain. The minimum company type experience requirement for the position was 500 hours. 

The DFO was interviewed by the ATSB and described the captain as having ‘significant operational experience in night freight operations and the ability to manage fatigue with appropriate rest which was a very important but often overlooked skill for a new captain.

The DFO also recalled that the FO had previously been an airline cadet (for a major carrier) and had performed well in their interview. 

No evidence of the ‘exceptional circumstances’ that led to the promotion of the captain or the employment of the FO was provided or identified by ATSB. There was also no evidence that ASL Airlines Australia had considered and managed the risks associated with the engagement of flight crew that did not meet the stated minimum requirements. 

The DFO explained that during the period after COVID‑19, other airlines were recruiting significant numbers of flight crew and that ASL Airlines Australia had less opportunity to recruit for experienced crew during that time. 

The Australian Government’s Aviation White Paper released in 2024 cited that a shortage of aviation professionals, including flight crew, was worsening, with job vacancies having more than tripled since 2019. The report also identified the effect a pilot shortage has on regional airlines and smaller operators, as crew leave these organisations to progress their careers with larger airlines, resulting in a higher turnover and a pool of less experienced applicants during recruitment.

Rostering of ‘inexperienced’ flight crew

The ASL Aviation Australia OM-A contained a policy to prevent ‘inexperienced’ flight crew being rostered together for a flight. It stated: 

A flight crew member is deemed to be 'inexperienced' following completion of a type rating or command course until achieving the following additional experience on the type in their respective flight crew role after a successful check-to-line: 

a. 100 flying hours and 10 operational sectors, within a consolidation period of 60 days; or 

b. 150 flying hours and 20 operational sectors (with no time limit). 

The policy further stated:

The OCC [Operations Control Centre] must ensure that inexperienced flight crew are not rostered together. In exceptional circumstances on Day of Operations the Director of Flight Operations may approve a crew complement that does not meet the above minimum experience requirements. To ensure compliance with current Regulations the Director of Flight Operations must ensure that, at an absolute minimum, the above minimum hours and sectors have been met when considering a crew member’s total type experience (including line training).

The captain had accumulated 198 hours since their successful check to line in February 2024 and was not considered inexperienced.

The FO had accumulated a total of 113 hours total time on the BAe 146 including their line training. Since their successful check to line on 29 May 2024, they had flown about 25 hours and completed 15 sectors as FO and was still considered ‘inexperienced’ according to the operator’s policy.

The policy did not have a provision for crew members that had been promoted to their position below the operator’s minimum prescribed hours.

Operational restrictions for 'inexperienced' flight crew 

CASA acceptable means of compliance guidance material regarding pilot experience, stated: 

The operator should consider any operational restrictions to be placed on an 'inexperienced' crew member after the completion of the conversion training or post command line check. These considerations may include cross wind limits, aerodrome limits and weather minima limits if the operator assesses these limits as suitable for their operation.

ASL Airlines Australia reported that it did not have a policy that restricted ‘inexperienced’ FOs landing in adverse weather and raised concern that this would reduce the exposure of FOs to less than desirable weather conditions.

The ATSB interviewed the captains of 2 of the 3 aircraft that were on approach to Brisbane ahead of VH‑SAJ. These aircraft were being operated by the same CASR Part 121 operator. Both captains advised that the FO on board was originally the pilot flying for that sector. However, if the visibility was less than 2,000 m or if the cloud was within 200 ft of the minima,[26] their operator’s policy was that the captain was required to conduct the approach and landing. Both captains reported that as the visibility on the ATIS was reported as 1,000 m and the cloud height at 200 ft, both had assumed the pilot flying roles of their respective aircraft prior to landing in accordance with their operator’s captains only approach procedure. 

The ATSB reviewed expositions from 6 CASR Part 121 operators and found that 5 out of 6 operators had restrictions on FO’s conducting take‑offs and landings in adverse weather conditions, including reduced visibility, low cloud and strong winds.

Responsibility for control of the aircraft

The ASL Airlines Australia OM-A stated:

The authority and responsibilities of the captain are crucial for the safe operation of an aircraft. The captain holds ultimate authority over the aircraft, maintains discipline, and is responsible for ensuring the safety of individuals and cargo onboard, as well as the overall safe operation of the aircraft.

During interview with the ATSB, the FO recalled that as the approach continued, they became uncomfortable with the reduced visibility and described feeling overwhelmed by the conditions. However, the cockpit voice recording indicated the FO did not advise the captain of this, and they continued the approach as pilot flying. The FO recalled that, in hindsight, they should have requested control handover to the captain when they started feeling uncomfortable. Additionally, the captain also reported that in hindsight they should have assumed control and landed the aircraft. 

The ASL Airlines Australia OM-A required: 

Handover of control from one pilot to another must always be conducted in a positive manner. To minimise confusion or operational risk, the PF must not relinquish control until the PM has advised that they have taken control of the aircraft. NOTE: The standard phraseology to be used for handover/takeover procedures is: "You have control" and "I have control". 

• In non-normal situations or when required, the Captain must initiate the takeover procedure.

• If corrected responses are not achieved from control inputs, control should be handed over to another flight crew member.

• In critical phases of flight, Captains must be in a position to enable rapid takeover of controls.

Standard calls

ASL Airlines Australia operations manual B (OM-B) for the BAe 146 detailed the required standard calls for flight crew during an approach. Cockpit voice recorder information indicated that the crew missed several required calls (Table 1).

Table 1: Standard calls on descent BAe 146

In addition to the standard calls, the ASL Airlines Australia OM-B for the BAe 146 stated that during landing the:

PF/PM must monitor the attitude – if the nose up attitude becomes excessive on the ADI the PF should stop the increase in pitch attitude and consider a go-around if necessary. Recommended attitudes at which an “attitude” call should be made by the PF are:

…

• BAe146-300: 5°

The cockpit voice recording indicated that no attitude call was made by the crew when the aircraft pitch attitude increased above 5° just prior to main gear touchdown.

Fatigue

General

Fatigue affects everyone regardless of skill, knowledge and training and its effects can be particularly dangerous in the transportation sector, including the aviation industry.

The International Civil Aviation Organization (ICAO, 2015) defined fatigue as a physiological state of reduced mental or physical performance capability resulting from sleep loss, extended wakefulness, circadian phase, and/or workload (mental and/or physical activity) that can impair a person’s alertness and ability to perform safety related operational duties. Fatigue can have a range of adverse influences on human performance. These include:

• slowed reaction time
• decreased work efficiency
• increased variability in work performance
• lapses or errors of omission (Battelle Memorial Institue, 1998).

Duty period and sleep obtained

ASL Airlines Australia exposition stated that when flight crew are rostered to begin a duty period between 0000 and 0459 and scheduled to fly 4 sectors, the maximum duty period is 9.5 hours. If both flight crew agree, the duty may be extended by 1 hour during the duty period.

The captain recalled not being rostered on for the previous 72 hours before they signed on for their duty period in Melbourne at about 0015. They reported that, on the Samn‑Perelli scale of alertness,[27] they felt fully alert, however at the time of the occurrence, reported they felt ‘okay, somewhat fresh’. The captain reported having about 5 hours sleep in the 24 hours prior to their duty period and about 12 hours of sleep in the past 48 hours.

The FO recalled not being rostered on for the previous 72 hours before starting their duty. They reported having about 9 hours sleep in the past 24 hours prior to their duty period and about 17 hours in the past 48 hours and that they felt ‘a little tired, less than fresh’ at the time of the occurrence. 

The ATSB assessed that both crew had sufficient sleep opportunity prior to commencing their duty.

Adequate sleep is an obvious prerequisite for alertness during duty. The concept of adequate sleep however is subject to individual variability with inconsistencies in amount and quality. 

Window of circadian low

The duty period required working through the time in the circadian body clock cycle when self‐rated fatigue and mood are worst (Salas & Maurino, 2010). According to ICAO (2015) there are 2 times of peak sleepiness within a 24‑hour cycle. The main peak is in the early morning between 0300‑0500 known as the window of circadian low (WOCL), another smaller peak is around 1500‑1700 known as the afternoon nap window (International Civil Aviation Organisation, 2015). For each individual this time can vary. The incident occurred at 0544 which was close to the WOCL, which would have had some impact on their alertness levels as seen in their subjective alertness ratings above. 

However, the FO’s alertness was possibly heightened (Causse and others, 2024) due to their unfamiliarity with the unforecast conditions and as a result this would likely have counteracted any effect of fatigue.

Operator's biomathematical model of fatigue

The operator provided the ATSB with a summary of the June 2024 report from their fatigue management software which uses biomathematical modelling to predict fatigue risk from the roster times and duty periods. The results did not identify fatigue risk had occurred with either crew member. However, the model does not account for individual susceptibility or resilience to fatigue. 

Fatigue summary

The ATSB considered the role of crew performance due to fatigue and found that the available evidence indicated that fatigue was unlikely to have contributed to the incident. However, the captain’s self-reported amount of sleep in the 24 hours prior to their duty period is below the guidelines for recommended hours (Hirshkowitz and others, 2015). 

Related occurrences

Tail strike – Brisbane Airport, Queensland, 23 October 2008 (AO‑2008‑74)

On 23 October 2008 at 2357 Eastern Standard Time, a BAe 146‑300 aircraft, registered VH‑NJM, operating a freighter flight, had a tail strike on landing at Brisbane Airport, Queensland. The aircraft and crew had commenced duty earlier that evening at Adelaide, South Australia, and had flown via Sydney, New South Wales, to Brisbane. The aircraft and crew then did the reverse sectors back to Adelaide. It was only after landing at Adelaide that the crew became aware of the tail strike. Damage to the aircraft consisted of abrasion to the tail strike indicator through to the fuselage skin and abrasion to the fuselage skin. There was also damage to the aircraft’s structural frame under the tail strike indicator. The aircraft manufacturer had identified an increase in the number of BAe 146‑300 tail strikes and has recommended a number of procedural changes for flight crew. The aircraft operator has implemented those changes and issued notices to flight crew highlighting the risks and conditions for tail strike.

Tail strikes during landing involving Bombardier DHC-8 402, VH‑QOT and VH‑QOS, Brisbane Airport, Queensland, on 5 November 2013 and Roma Airport, Queensland, on 11 December 2013 (AO-2013-201)

On 5 November 2013 and 11 December 2013, 2 Dash 8‑400 aircraft, registered VH‑QOT and VH‑QOS, were being operated by QantasLink on scheduled passenger flights from Roma to Brisbane and Brisbane to Roma, Queensland, respectively. Both flights were crewed by a training captain, operating as pilot monitoring, and a trainee first officer, operating as pilot flying.

Although the 2 approaches utilised different flap settings, both were conducted using a propeller setting of 1,020 RPM. The early, initial and final stages of the approaches were unremarkable. Both training captains reported that as the aircraft approached the flare, they thought that the respective trainees had handled the approach well.

During landing, both trainees arrested the descent rate by raising the nose of the aircraft. In both cases the maximum pitch attitude was exceeded and the aircraft’s tail contacted the runway. Each aircraft sustained impact and abrasion damage to the fuselage skin and buckling of internal structures in the area of the tail strike sensor.

Safety analysis

Introduction

On 25 June 2024, a British Aerospace BAe 146‑300, registered VH‑SAJ, was being operated by ASL Airlines Australia on a freight flight from Sydney, New South Wales to Brisbane, Queensland. There were 2 flight crew on board. The captain was pilot monitoring (PM), and the first officer (FO) was pilot flying (PF). 

While on descent to Brisbane, the meteorological conditions worsened with visibility reducing to about 1,000 m in fog. The crew conducted an instrument landing system (ILS) approach for runway 19L, using the autopilot, and visually identified the high intensity approach lighting at about 220 ft. The FO disconnected the autopilot at about 110 ft and made control inputs that resulted in an increasing aircraft pitch attitude followed by several corrections and continued decreasing airspeed. The aircraft touched down with a high pitch angle and a vertical acceleration of about 2.4 g. The tail of the aircraft struck the runway, resulting in damage to the tail strike indicator and surrounding panels.

This analysis will explore the operational considerations pertaining to flight crew experience and training, situation awareness, command decision‑making and crew communication.

Loss of situation awareness

The FO was new to their position with ASL Airlines Australia, having been checked to line 28 days prior to the incident. During their line training, the FO required additional simulator and supervised line flying sectors to achieve the required standard associated with situation awareness, approach and landing. At the time of the incident, the FO had accumulated a total of 113 hours of flying on the BAe 146.

The meteorological conditions at Brisbane at the time of the approach included reduced visibility due to the formation of advected fog. At the time the crew reached the ILS decision altitude (DA) for runway 19L, the visibility was recorded as 912 m. Although this exceeded the minimum required for the approach, the FO had only experienced flying in reduced visibility during their BAe 146 simulated training, and they had not previously landed an aircraft in foggy conditions. (The FO’s experience prior to employment with the operator had predominately been flying smaller single engine aircraft in visual meteorological conditions).

The presence of low cloud or fog can create a false visual reference which can result in a pilot orientating the aircraft to the fog layer, rather than the ground references (Federal Aviation Administration). The FO recalled that the low cloud and fog created a sight picture that they had not previously experienced in the aircraft and that following the transition to visual flying, their instrument scan pattern broke down as their attention shifted to outside the aircraft as they attempted to make sense of the landing environment. 

Research by Garland et al, (1999) identified that high mental workload can negatively impact situation awareness, as only a subset of the available information can be processed and acted upon. Situation awareness can be defined as ‘the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning and the projection of their status in the near future’ (Endsley, 1988) . The maintenance of a high level of situation awareness is a critical feature of a pilot’s role (Garland et al, 1999). 

The combination of degraded visibility, potential visual illusion, high workload, and inexperience operating in similar meteorological conditions likely resulted in the FO losing situation awareness of the aircraft state. Consequently, the FO did not effectively manage the aircraft following the disconnection of the autopilot resulting in the aircraft initially becoming high on the approach. 

A short time later, the FO likely became aware of the high profile and attempted to correct the height with several pitch attitude changes. However, the FO’s attention was outside the aircraft at this time and their instrument scan had broken down. 

Consequently, they were likely not monitoring aircraft airspeed and did not command any change to the engine power settings. As a result, the airspeed reduced and the aircraft’s rate of descent increased. The FO likely identified the increased rate of descent as the aircraft neared the runway, as a large pitch attitude increase was recorded just prior to touchdown. However, these actions were not sufficient to arrest the high rate of descent and this, in combination with the high pitch attitude, resulted in the tail of the aircraft striking the runway surface.

Captain’s focus on remaining fuel

As a consequence of the unforecast reduction in visibility, with no original requirement to plan an alternative airport, the captain became increasingly concerned about the fuel state as the aircraft continued on the approach.

It was also an expectation of the captain that the visibility would deteriorate further, commenting to the FO that if they were to conduct a go-around this could potentially leave them in a worse situation. During the approach, the captain also made several remarks about committing to a landing including that if they could see the high-intensity approach lighting, then they were going to land. About 2 minutes prior to landing, the FO expressed concern regarding the autopilot usage stating that they would disconnect it should a go‑around be required. In response, the captain stated ‘we don't want to go around. It’s gonna be a world of hurt’.

Prior to their descent into Brisbane, the crew had calculated the minimum fuel to divert to the Gold Coast was about 1,700 kg. The aircraft landed at Brisbane with about 2,300 kg of fuel on board, indicating there was sufficient fuel to conduct a go-around at Brisbane and safely divert the aircraft to the Gold Coast.

The captain’s preoccupation with the aircraft fuel state, combined with the expectation of worsening conditions, led to an increased desire to land the aircraft on the first approach and avoid conducting a go‑around which they perceived would have resulted in an approach in conditions that would likely deteriorate further.

Continued communication regarding fuel

Brisbane air traffic control (ATC) had alerted the crew to the approaching low cloud bank about 18 minutes prior to landing. From the time of the alert until the landing, the CVR recorded continued concern from the captain. 

This concern included that they had ‘no fuel’ and ‘we haven't got the fuel for this’ as well as concern with the conditions stating, ‘the weather will only get worse’ and ‘if we can see the HIAL’s,[28] we’re going to land’. 

About 4 minutes prior to landing, the FO asked if it was possible to calculate the fuel needed to divert to the Gold Coast, to which the captain responded ‘not now, on final, but let's try and get in’. Shortly after the FO discussed the go‑around procedure in preparation for the DA, to which the captain reinforced their intention to land.

Although there was continued communication regarding the fuel state and visibility, no discussion was recorded regarding diversion plans to an alternative airport until established on the final approach. Additionally, the crew did not proactively obtain the weather conditions for alternate aerodromes, in the event that they were required to conduct a go-around without a planned diversion, limiting the crew’s options to return to conduct a second approach in Brisbane, further exacerbating the expectation of landing off the approach.

In contrast, the crew of the preceding aircraft on the approach prior to VH‑SAJ, advised that there was sufficient time during descent to plan for a diversion on receipt of the weather changes. Subsequent ATC recordings indicated that this crew also advised ATC of their intention to divert to the Gold Coast, if a go-around was required.

The FO had no previous experience in a multi‑crew environment and had only recently been checked to line. According to Fabre (2022), when a newly appointed FO is paired with a captain that they consider as experienced, the captain’s opinion strongly influences the FO’s decision‑making and significantly increases the likelihood of the crew attempting a moderate to high-risk landing scenario. The FO’s limited experience in the position and in a multi‑crew environment likely meant they were more susceptible to the captain’s pressure to land and less likely to voice any concerns.

The continued verbal concern over landing off the approach compounded pressure on the FO, which likely compelled them to commit to a landing on reaching the DA.

Crew appointments

The ASL Airlines Australia operations manual outlined the minimum experience requirements for the appointment of captains and first officers. However, neither the captain nor the FO met these requirements at the time of their engagement, nor at the time of the incident. 

In ‘exceptional circumstances’, the ASL Airlines Australia operations manual permitted the variance of the experience requirements with the specific approval of the director of flight operations. 

There was no evidence that ASL Airlines Australia had considered the hazards associated with the appointment of pilots that did not hold the required level of experience, nor was any control put in place to manage the risks. Such controls could have included, but were not limited to, operational limitations for low experience crew. The ATSB reviewed expositions from 6 CASR Part 121 operators and found that 5 had restrictions on FOs conducting landings in marginal meteorological conditions, including reduced visibility and low cloud. 

ASL Airlines Australia did not have such a policy, and it reported that having similar limitations could lead to FOs being promoted to captain without having acted as pilot flying in adverse weather conditions. However, the FO’s limited experience in marginal meteorological conditions likely contributed to the tail strike incident. Had a similar limitation been in place, it would likely have resulted in the captain assuming control when the crew were alerted to the low visibility at Brisbane Airport. 

ASL Airlines Australia had a rostering policy that prevented crew who had not accumulated 100 hours in their positions from being rostered together. However, there was no consideration made for crew who had been provided early promotion to their positions. As a result, the captain, promoted early to their position and at the time of the occurrence had not yet attained the minimum experience requirements to hold the position, was paired with an inexperienced FO. Without administrative controls in the rostering policy to prevent unsuitable pairing of crew without requisite experience, the result was a reduction in the intended experience level on the flight deck for the incident flight.

Captain’s multi-crew experience 

The captain commenced with ASL Airlines Australia in November 2022, initially as a FO, before undertaking command upgrade training after 155 hours. They had held the position since February 2024 and had accrued 198 hours as a captain at the time of the incident. Prior to joining ASL Airlines Australia, the captain had not flown a jet aircraft and had mostly flown in single pilot operations. As discussed above in Crew appointments, the captain had been nominated for command upgrade training below the required 500 hours, and this reduced their opportunity: 

• to gain valuable exposure operating in a multi-crew environment
• to model behaviour on experienced captains’ decision making

prior to commencing in the captain role themselves. 

The missed opportunity to gain valuable multi-crew experience likely impacted the captain’s capacity to include the FO in the decision‑making process and limited the effectiveness of the crew during the approach. Although the captain was not the PF during the approach, the ultimate responsibility for the safety of the aircraft lay with them. The cockpit voice recording indicated that, although it was reasonable for the captain to assume the FO was competent in flying the ILS, they did not ask the FO if they were comfortable to continue the approach after being alerted to the low cloud, fog and changing weather conditions. Likewise, while the FO did not advise the captain that they were experiencing difficulties during the approach, the captain did not recognise other cues, such as the FO’s response when requested to disconnect the autopilot at the DA, their ability to clearly see the approach lighting on short final, or their obvious discomfort with the approach. 

It is likely that the captain’s limited command multi-crew experience may also have reduced their ability to establish an appropriate ‘cockpit gradient’ following advice that the meteorological conditions at Brisbane Airport were deteriorating. The term ‘cockpit gradient’ describes the level of authority that exists between the crew members, and the way this authority influences communication and decision‑making. Although the pilot in command has ultimate responsibility in terms of decision‑making, depending on the cockpit gradient, other crew members can be either encouraged or discouraged from influencing these decisions through their own inputs. 

A ‘steep’ cockpit gradient exists when the pilot in command has an overwhelming influence in decision‑making, with little input sought from other crew members. A steep gradient can ‘inhibit communication, coordination and the cross-checking of errors’ (Harris, 2011). The cockpit voice recording indicated a steep cockpit gradient existed during the approach phase, with the captain dismissing the FO’s request to recalculate diversion fuel or plans in the event of a go-around, thereby reducing the effectiveness of the decision‑making process.

The captain provided control input instructions to the FO during the final stages of the approach. Likely due to their limited experience in the captain role, they did not recognise that the approach would have been better handled by a more experienced crew member who had previously encountered comparable conditions. Consequently, no authoritative decision was made by the captain to assume the PF role or to command a go‑around when the aircraft entered an undesired state after autopilot disconnection. 

Captain’s control input

The captain reported that as the high sink rate developed, they anticipated the FO’s reaction and placed their hand on the control column to prevent any further increase in the aircraft’s pitch during the landing. This likely reduced the severity of airframe damage caused by the tail strike.

ASL Airlines Australia procedures stated that any control handover must be conducted in a positive manner to minimise confusion and operational risk. The FO recalled feeling the captain’s pressure on the control column preventing further rearward input, but the captain did not verbalise their actions at the time. While the control column input from the captain may have prevented further damage to the aircraft, it also risked confusion about who was in control of the aircraft during a critical stage of flight. 

Findings

From the evidence available, the following findings are made with respect to the ground strike involving British Aerospace BAe 146‑300, registered VH‑SAJ on 25 June 2024.

Contributing factors 

• The first officer became disoriented after disconnecting the autopilot on short final and likely lost situation awareness. Consequently, they did not identify the increasing aircraft pitch attitude, decreasing airspeed, or low power setting and did not correct the resulting sink rate prior to touchdown.
• The captain became preoccupied with remaining fuel. This combined with an expectation of worsening visibility resulted in a sense of urgency to land off the first approach.
• Repeated communications from the captain regarding the need to land off the first approach likely increased pressure on the first officer to commit to a landing.
• ASL Airlines Australia employed and promoted pilots earlier than the prescribed minimum experience hours without additional controls in place to manage the risk of lower experienced pilots on the flight deck. (Safety issue)
• The captain’s limited command experience in a multi-crew environment likely reduced their capacity to include the first officer in the decision‑making process, consider the need to assume the pilot flying role or command a go-around when the aircraft entered an undesired state during landing

Other findings

• The captain prevented further rearward input by the first officer during the flare by placing their hand on the control column. While this action is not usually completed without the required takeover procedure it likely reduced the severity of the tail strike.

Safety issues and actions

Employment and promotion of pilots earlier than company minimum hours

Safety issue number: AO-2024-036-SI-01

Safety issue description: ASL Airlines Australia employed and promoted pilots earlier than the prescribed minimum experience hours without additional controls in place to manage the risk of lower experienced pilots on the flight deck.

Additional safety action by ASL Airlines Australia

The operator’s internal review identified an inconsistency between the operator’s standard operating procedures and the manufacturer’s recommendation with regard to which pilot (the pilot flying or the pilot monitoring) was to make an ‘attitude’ call when the aircraft pitch angle approaching landing increased above 5°.

ASL Airlines Australia’s internal investigation of the occurrence will be incorporated into the relevant sections of the ASL Airlines Australia HF/NTS training.

A summary of the internal investigation will also be included in the operator’s internal safety publication.

Glossary

Sources and submissions

Sources of information

The sources of information during the investigation included:

• ASL Airline Australia flight records from the occurrence aircraft
• ASL Airlines Australia Operations Manuals and Standard Operating Procedures for the BAe 146
• the captain and first officer of the occurrence aircraft
• the director of flying operations, ASL Airlines Australia
• Civil Aviation Safety Authority
• BAE Systems
• Airservices Australia
• cockpit voice recorder and flight data recorder
• Brisbane Airport Corporation CCTV images
• the captains from the 2 preceding aircraft to VH-SAJ
• Bureau of Meteorology
• Flight Radar24
• Google Earth

References

Australian Transport Safety Bureau. (2009). Tail Strike, Brisbane Airport, Queensland, on 23 October 2008, VH-NJM, British Aerospace BAe 146-300. Retrieved from /publications/investigation_reports/2008/aair/ao-2008-074

Australian Transport Safety Bureau. (2016). Tail strikes during landing involving Bombardier DHC-8 402, VH-QOT and VH-QOS, Brisbane Airport, Queensland, on 5 November 2013 and Roma Airport, Queensland, on 11 December 2013. AO-2013-201.

Causse. (2024). How a pilot's brain copes with a stress and mental load.

Civil Aviation Safety Aurthority. (2024). Civil Aviation Safety Regulations 1998. Retrieved from CASR 121.495: https://www.legislation.gov.au/F1998B00220/latest/text/3

Endsley, M. (1988). Design and evaluation for situation awareness enhancement. Proceedings of the Human Factors Society 32nd Annual Meeting , 97-101.

Fabre, D. E. (2022, June). AXA. Retrieved from Hierarchy in the cockpit: understanding decision making at the time of landing: https://www.axa.com/en/insights/hierarchy-in-the-cockpit-understanding-…

Federal Aviation Administration. (n.d.). Spatial Disorientation Visual Illusion.

Garland, D. W. (1999). Handbook of Aviation Human Factors. Mahwah, NJ.

Harris, D. (2011). Human Performance on the Flight Deck. Ashgate Surrey, England.

Hirshkowitz, M. W.-4. (2015). National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep health.

Institute, Battelle Memorial. (1998). An Overview of the scientific literature concerning fatigue, sleep and the circadian cycle.

International Civil Aviation Organisation. (2015). ICAO, Fatigue Management Guide for Airline Operators. Retrieved from ICAO:

Roach, G. D. (2004). A model to predict work-related fatigue based on hours of work. Aviation, Space and Environmental Medicine,.

Salas, & Maurino. (2010). Human Factors in Aviation, Second edition. 

United Kingdom Civil Aviation Authority. (2023). Flight-crew human factors handbook. Retrieved from https://www.caa.co.uk/publication/download/14984

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report. 

A draft of this report was provided to the following directly involved parties:

• Director of Safety, ASL Airlines Australia
• the captain
• the first officer
• Civil Aviation Safety Authority
• Air Accidents Investigation Branch, United Kingdom
• Part 121 aircraft operator (party with involvement)
• Bureau of Meteorology
• Airservices Australia.

Submissions were received from:

• the captain
• ASL Airlines Australia
• Civil Aviation Safety Authority
• Bureau of Meteorology.

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through:  identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2025 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Commonwealth Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this report is licensed under a Creative Commons Attribution 4.0 International licence. The CC BY 4.0 licence enables you to distribute, remix, adapt, and build upon our material in any medium or format, so long as attribution is given to the Australian Transport Safety Bureau.  Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Executive summary

What happened

On 6 February 2024, a student pilot and flight instructor conducted a dual training flight from Gold Coast Airport, Queensland, in a Cessna 172R aircraft, registered VH-EWW. On their return, the student received an initial air traffic control clearance to track direct to runway 32. 

About 40 seconds later, the flight crew accepted an amended clearance to track to the shorter runway 35 at ‘best speed’. When VH-EWW was at 1,000 ft and 1.9 NM from the runway 35 threshold, the flight crew were cleared to conduct an approach and maintain ‘best speed all the way in to crossing the runway’. Unsure how to comply with that instruction, the instructor directed the student to reduce the throttle to idle and lower the aircraft’s nose.

The aircraft subsequently passed about 100 ft above the runway threshold at about 25 kt faster than the normal approach speed. As a result, the aircraft floated along the runway before it touched down and bounced once. During the landing roll, as the aircraft approached the end of the runway, the instructor took over control of the aircraft from the student. They attempted to brake and turn the aircraft onto a taxiway beyond the end of the runway. During the turn, the aircraft veered off the taxiway towards a ditch. In response, the instructor applied back pressure on the control column and full power to commence a go-around, during which the rear fuselage and tail struck the ground. A right circuit and landing to runway 32 was then conducted.

What the ATSB found

The ATSB found that the air traffic controller's request to maintain best speed to the runway, combined with the instructor's interpretation of the instruction, resulted in an excessively fast approach. Although the aircraft exceeded both the manufacturer’s approach speed and the operator’s stabilised approach speed, the instructor did not conduct a go-around prior to landing or while on the runway. This resulted in the aircraft landing long and fast. 

The excessive landing speed also resulted in reduced braking effectiveness and a loss of control during the turn onto the taxiway. Following the loss of control, a go-around was initiated to avoid a drainage ditch, resulting in a ground strike and near collision with hangars located on the eastern boundary of the airport.

What has been done as a result

The aircraft operator reviewed the company’s standard operating procedures for stabilised and unstable approaches. They also reviewed training material and sequences for instructors and students, including human factors aspects regarding communication, decision making and assertiveness.

Finally, the operator and their instructor team discussed training challenges at Gold Coast Airport with a focus on non-standard air traffic control requests and clearances, including the refusal of clearances considered operationally unacceptable. 

Safety message

Although not standard phraseology, air traffic controllers may ask pilots to maintain ‘best speed’. It is up to the pilot to determine what is best in this context and more generally advise if an instruction is unclear or cannot be complied with. An approach must be flown in accordance with the aircraft flight manual and operator’s procedures. Landing with excessive speed is likely to result in the aircraft floating, landing long on the runway, bouncing and/or ballooning, all of which increase the risk of a landing mishap.

When operating in visual meteorological conditions, if an approach is not stabilised by the height specified by the operator (or generally by about 500 ft above the ground), or becomes unstable after that point, a go‑around should be conducted. The Flight Safety Foundation’s briefing note Being prepared to go around, emphasises the importance of being go-around-prepared and go‑around‑minded. This includes being ready to conduct a go‑around during the approach if any desired flight parameter, such as aircraft configuration, vertical speed, airspeed, or attitude cannot be achieved.

The investigation

The occurrence

On 6 February 2024, a student pilot and flight instructor were conducting a dual training flight in a Cessna 172R aircraft, registered VH-EWW. The aircraft took off from Gold Coast Airport, Queensland, at about 1138 local time, and tracked to the locality of Baryulgil, New South Wales (NSW), where the flight crew conducted aerial work overhead. The aircraft then tracked to Casino Aerodrome, NSW, where the student conducted 5 circuits, before departing at about 1354 to return to Gold Coast Airport (Figure 1). 

Figure 1: VH-EWW track Gold Coast – Baryulgil – Casino – Gold Coast

Source: Google earth overlaid with Airservices Australia radar data, annotated by the ATSB

At about 1419, when VH-EWW was about 10 NM south-west of Gold Coast Airport, the student pilot contacted Gold Coast Tower air traffic control. The student pilot advised that they were inbound and requested a clearance to enter controlled airspace. The aerodrome controller (ADC) issued the flight crew a clearance to track direct to the airport at 1,500 ft and advised them to expect runway 32. The ADC subsequently cleared the flight crew to descend to 1,000 ft. At that time, VH-EWW was 6.3 NM from the airport and tracking towards a right base leg[1] for runway 32. 

About 40 seconds later, to facilitate sequencing with other aircraft, the ADC asked the VH-EWW flight crew whether they could ‘accept runway 35, best speed’. The student pilot reported looking at the instructor and shaking their head thinking the aircraft was too high and close to that runway. At that time, VH-EWW was 3.9 NM from the threshold of runway 35, which was 582 m long, and significantly shorter than runway 32, at 2,492 m (Figure 2). The student’s assessment was probably due to inexperience, having only landed on runway 35 once before. Had they been cleared to commence the approach from that position, a landing should have been readily achievable, with an approach profile of about 2.4°. 

Figure 2: Gold Coast Airport showing runways 32 and 35

Source: Google earth, annotated by the ATSB

The instructor assessed that, as there was a headwind of about 14 kt, the aircraft could land safely on runway 35 from that position, and it would be a good opportunity for the student to practise landing on the shorter runway. The instructor therefore responded ‘affirm’ to the ADC. The ADC then issued a clearance to track for a straight-in approach to runway 35 at ‘best speed’ and advised the flight crew that they would shortly be cleared to descend. 

Just over 1 minute later, the ADC cleared the flight crew to conduct a visual approach, and stated, ‘I need best speed all the way in to crossing the runway’. According to radar data, VH-EWW was then 1.9 NM from the runway 35 threshold, at about 1,000 ft and 90 kt ground speed.

The student and instructor later reported that, although on previous flights they had received air traffic control instructions to maintain best speed, these had been up to the commencement of an approach. They had not previously received a clearance for a visual approach and best speed to the runway, and were unsure what was expected.

In an attempt to comply with the clearance, the instructor advised the student to reduce the throttle to idle and lower the aircraft’s nose to maintain best speed. When the airspeed was below 110 kt, the student extended the flaps 10°. Further flap extension required a maximum airspeed of 85 kt. As the airspeed remained at or above 90 kt for the remainder of the approach, the flaps were not subsequently extended to the normal 30° landing configuration. 

According to radar data, VH-EWW was about 1 NM from the runway 35 threshold, descending through about 500 ft at 95 kt ground speed, when the ADC cleared the flight crew to land and to ‘continue to taxi into GOLF’ (Figure 3 and Figure 4). This was to reiterate that they were cleared to continue through the runway 32 intersection. As VH-EWW approached the runway, the controller observed that the aircraft appeared to be faster than normal and, expecting the flight crew would conduct a go-around,[2] started planning to re-sequence the aircraft. 

Figure 3: VH-EWW track showing positions of key air traffic control communications

Source: Google earth overlaid with Airservices Australia radar data, annotated by the ATSB

The aircraft crossed the runway 35 threshold at about 100 ft and 90 kt indicated airspeed (about 80 kt ground speed). The aircraft floated in ground effect just above the runway for a significant period before it briefly touched down and bounced/ballooned once. The instructor advised the student to continue the landing rather than go around. The instructor reported that this was based on their experience of normal operations on runway 32, which had sufficient runway length to decelerate following a fast approach and long float prior to touchdown. When the aircraft landed long on runway 35 and the student commenced braking, the wheels locked up. The instructor then took over control of the aircraft from the student and reported applying firm back pressure to the control column in an attempt to increase the weight on wheels to assist with the braking. However, the application of heavy braking still resulted in the brakes locking the wheels. 

The instructor assessed that the aircraft was still travelling faster than expected. At this stage the aircraft was past the runway 32 intersection and rapidly approaching the end of the runway. Seeing this, the ADC stated, ‘turn up [taxiway] CHARLIE if need be’, to alert the flight crew that they could make a 20° left turn onto that taxiway, instead of a 66° right turn onto GOLF. The instructor heard the call but did not recognise the alternate option, as they were focused on making the turn onto GOLF (Figure 4).

Figure 4: Gold Coast Airport taxiways CHARLIE and GOLF, drainage ditch, hangars and VH-EWW track 

Source: Google earth overlaid with Airservices Australia radar data, annotated by the ATSB

During the turn, the aircraft skidded left off the taxiway onto grass and towards a drainage ditch. The instructor then applied full power and back pressure on the control column to clear the ditch, which resulted in a ground strike, damaging the rear fuselage (Figure 5). Having observed the aircraft exit the taxiway, the ADC activated the crash alarm[3] to alert aviation rescue fire fighters. 

Figure 5: Ground strike damage to VH-EWW

Source: Aircraft operator, annotated by the ATSB

Unaware of the ground strike, the instructor commenced a go-around, with the aircraft climbing towards a row of hangars. The instructor turned the aircraft slightly right towards the lowest roof to maximise the clearance from the buildings. The instructor reported that the stall warning horn[4] was sounding, and therefore they had to lower the aircraft’s nose to prevent a stall, but also maintain a high enough nose attitude for the aircraft to climb above the hangar (Figure 6). The instructor advised the ADC that they ‘just had to make an emergency go-around’. 

Figure 6: Image from CCTV footage showing VH-EWW passing close above hangars

Source: Gold Coast Airport Limited, annotated by the ATSB

The ADC handed over aerodrome control duties to another controller, who advised the VH-EWW flight crew they had had a tail strike and confirmed they anticipated being able to conduct a normal approach and landing. The instructor then conducted a right circuit, with a left orbit on downwind as required by air traffic control for spacing, and landed on runway 32 at about 1434.

Context

Approach airspeeds

According to the Cessna 172R Pilot’s Operating Handbook (POH), the aircraft’s power-off stall speed was 47 kt with full (30°) flap and 51 kt with the flaps retracted. The handbook also provided the following approach speeds:

Table 1: Airspeeds for normal operation – approach 

Landing distance required

The automatic terminal information service current at the time of the accident broadcast the following: temperature 31 °C, QNH[5] 1008 hPa, wind from 010° (magnetic) at 15 kt. For runway 35, this equated to a headwind component of 14 kt and a crosswind of 5 kt. Gold Coast Airport aerodrome elevation is 21 ft above mean sea level. The calculated pressure altitude[6] was 171 ft and the density altitude[7] was 2,091 ft. 

The pilot’s operating handbook provided a chart for calculating the landing distance required at the aircraft’s maximum weight. The distances were based on a short field landing technique with flaps 30°, power off, maximum braking, paved level dry runway, nil wind and 62 kt indicated airspeed at 50 ft above the ground. It also advised to decrease distances 10% for each 9 kt of headwind. Further, if landing with flaps up, increase the approach speed by 7 kt indicated airspeed and allow for 35% longer distances. There was no data for landing with flaps 10°, or for landing at a higher indicated airspeed.

At flaps 30°, sea level pressure altitude and 30 °C, the ground roll distance required was 177 m and the total distance required to clear a 50 ft obstacle (on the approach path) was 408 m. The beneficial effect of the 9 kt headwind reduced these distances to 159 m and 368 m respectively. If landing with the flaps retracted, the required approach speed was 69 kt, ground roll 215 m and distance to clear a 50 ft obstacle 496 m. 

Speed control

The Airservices Australia Aeronautical Information Publication (AIP) listed standard air traffic control phraseologies, including for speed control. ‘Best speed’ was not a standard phrase however, the AIP also stated that clear and concise plain language should be used where no phraseology was available. In the section regarding speed control for arriving aircraft, the AIP stated that a clearance for a visual approach ‘terminates speed control’. Airservices Australia advised that this meant termination of previous speed instructions but did not preclude a controller issuing subsequent speed control instructions for sequencing. Further, speed control instructions to flight crew conducting visual approaches were frequently issued. 

Additionally, the Airservices Australia Manual of Air Traffic Services section Speed control principles included ‘Do not vary the final approach speed’. That manual defined final approach as ‘That part of an instrument approach procedure which…commences at the specified final approach fix or point…ends at a point in the vicinity of an aerodrome from which…a landing can be made; or…a missed approach is initiated’. In response to the draft report, Airservices Australia reiterated that the term final approach only applied to aircraft conducting an instrument approach, therefore was not applicable when flight crew were conducting a visual approach. 

The aerodrome controller issued the ‘best speed’ instruction to the VH-EWW flight crew to facilitate traffic flow. The controller estimated that had the flight crew conducted a normal approach, there would probably have been insufficient spacing for VH-EWW to land before an inbound Boeing 737. The controller reported that flight crew of training aircraft sometimes deliberately conducted very slow approaches. Further, that the approach speeds of similar aircraft to the Cessna 172 could vary by 20 to 30 knots, but the landing speed would be essentially the same. In issuing the instruction, the ADC expected that the flight crew would maintain a higher speed until the aircraft was a bit closer to the airfield than normal, and then reduce speed appropriately to make a safe landing. 

The AIP Speed control section also included:

5.2 The pilot must request an alternative when an ATC-issued speed control instruction is unacceptable on operational grounds. 

The instructor reported that during the approach, they wanted to help the ADC by getting in quickly, and not impeding the Boeing 737. After the incident, the instructor reported that in future they would be more assertive with air traffic control and advise they could not comply with maintaining best speed while conducting a normal approach. 

Stabilised approach 

The United States Federal Aviation Administration’s (FAA’s) Airplane Flying Handbook defined a stabilised approach as:

one in which the pilot establishes and maintains a constant-angle glide path towards a predetermined point on the landing runway. It is based on the pilot’s judgment of certain visual clues and depends on maintaining a constant final descent airspeed and configuration.

The handbook further stated that for a general aviation piston-engine aircraft, an immediate go‑around should be initiated if an approach became unstable below 300 ft above the ground. The handbook listed criteria for a stabilised approach. These included a criterion for airspeed. For a stable approach, the airspeed was to be within +10 and -5 kt of the recommended landing speed specified in the aircraft flight manual, 1.3 x stalling speed or an approved placard/marking. 

The FAA fact sheet Stabilized approach and landing, described an optimum 3° glideslope. The fact sheet referenced a study that found unstable approaches with a glideslope greater than 3° often had high descent rates and approach speeds. 

The operator of VH-EWW prescribed stabilised approach criteria in the operations manual. When operating in visual meteorological conditions[8] the criteria were, when below 300 ft: 

• in the landing configuration
• on the correct flight path
• only small changes in heading and pitch required to maintain the correct flight path
• speed stabilised at not more than the reference landing speed[9] [in this case 61 kt with full flap and 66 kt with the flaps retracted] plus 10 kt and not less than the reference landing speed
• sink rate of not more than 1,000 feet per minute
• the power setting is appropriate for the aircraft configuration and is not below the minimum power for the approach as defined by the aircraft operating manual.

Safety analysis

When the aerodrome controller cleared the flight crew to conduct a visual approach and to maintain best speed until crossing the runway, their expectation was that the flight crew would initially maintain a higher airspeed, but reduce to normal final approach speed as required for a safe landing. However, the flight crew were uncertain how to comply with the instruction, having previously only been requested to maintain best speed up until the commencement of an approach. Despite that, the flight crew did not seek clarification from the controller, or advise that they were unable to comply with the speed requirement. 

When the flight crew were issued the clearance to conduct a visual approach, the aircraft was at about 1,000 ft and 1.9 NM from the runway threshold. A stabilised approach is generally based on a 3° approach profile. In this case the aircraft’s flight path to the threshold was steeper at about 5° (to the horizontal). To achieve that flight path, and maintain what they interpreted as the required airspeed, the crew reduced the throttle to idle and lowered the aircraft’s nose. Those actions resulted in an approach airspeed significantly faster than that published in the POH. 

The phrase ‘best speed’ used by the controller was not included in the standard air traffic control phraseology published in Airservices Australia’s Aeronautical Information Publication (AIP). However, controllers could use clear and concise plain language when a standard phrase did not exist. In this instance, the controller’s emphasis to maintain best speed until within the vicinity of the runway contributed to the aircraft’s excessive airspeed.

Based on published landing data, runway 35 was long enough for the aircraft to land at maximum weight, even using a normal landing technique with the flaps retracted. However, VH‑EWW’s 90 kt airspeed when it crossed the runway threshold was 15 kt higher than the upper limit of the flapless approach speed specified in the POH. Additionally, the aircraft’s approach speed exceeded the operator’s stabilised approach criteria for the airspeed to be not more than the reference landing speed (61–66 kt depending on flap setting) plus 10 kt, which should have prompted the flight crew to initiate a go-around. 

The instructor’s expectation that they could remedy the effects of the fast approach on the runway, rather than having to go around, was based on usually landing on runway 32, which was more than 4 times the length of runway 35. The flight crew therefore continued the approach, resulting in the aircraft floating above the runway and landing a long way down the runway. Because of the higher airspeed (and possibly the extended flap) reducing the load on the wheels, when the aircraft landed brake application locked the wheels despite the instructor’s application of back pressure on the control column. 

Although still travelling at speed, the instructor attempted to turn onto taxiway GOLF. The instructor did not identify the controller’s intent for them to make a much smaller left turn onto taxiway CHARLIE, while focused on trying to achieve the right-hand turn onto GOLF. The turn at speed resulted in the aircraft skidding off the side of the taxiway into grass. 

The instructor’s application of full throttle and back pressure to avoid the aircraft nosing forward into a ditch resulted in the fuselage and tail striking the ground. Unaware that the ground strike had occurred, the instructor initiated a go-around from the grass. By that stage, the airspeed had reduced such that the stall warning indicated an impending stall. The instructor’s action to lower the aircraft’s nose prevented the stall but resulted in a low climb gradient and near collision with hangars.

Findings

From the evidence available, the following findings are made with respect to the taxiway excursion, ground strike and near collision with terrain, involving Cessna 172R, VH-EWW, at Gold Coast Airport, Queensland, on 6 February 2024. 

Contributing factors

• The air traffic controller's requirement to maintain best speed to the runway, combined with the instructor's interpretation of the instruction, resulted in an excessively fast approach.
• Although the aircraft exceeded the speed for a stabilised approach, the instructor did not conduct a go-around prior to landing or while on the runway.
• The excessive landing speed resulted in reduced braking effectiveness and a loss of control during the turn onto the taxiway.
• Following the loss of control, a go-around was initiated to avoid a drainage ditch, resulting in a ground strike and near collision with hangars located on the eastern boundary of the airport.

Safety actions

The aircraft operator advised that the following safety actions had been taken:

• The safety committee reviewed the company’s standard operating procedures for stabilised and unstable approaches. Company procedures and training were found to be aligned with the United States Federal Aviation Administration Private Pilot – Airplane Airman Certification Standards – Short field approach and landing speed tolerance (+10/-5 knots with gust factor applied) and the Civil Aviation Safety Authority’s Part 61 Manual of Standards Schedule 8, Table 1 Final approach speed tolerance (+5/-0 knots).
• A review of training material and sequences for instructors and students, including human factors aspects regarding communication, decision making and assertiveness.
• Discussions with the instructor team focused on training challenges at Gold Coast Airport for non-standard air traffic control requests and clearances, including refusal of clearances considered operationally unacceptable. 

Sources and submissions

Sources of information

The sources of information during the investigation included:

• the student pilot, instructor and air traffic controller
• the operator
• Airservices Australia
• video footage of the accident flight. 

References

Federal Aviation Administration (2021). Airplane Flying Handbook, FAA-H-8083-3C. US: FAA. Retrieved from: https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/airplane_handbook 

Federal Aviation Administration (2022). Stabilized approach and landing, AFS-850 20-04. US:FAA. Retrieved from: Stabilized Approach and Landing (faa.gov) 

Flight Safety Foundation (2000). FSF Approach and Landing Accident Reduction Briefing Note 6.1– Being prepared to go around. US:FSF. Retrieved from: https://flightsafety.org/files/alar_bn6 1-goaroundprep.pdf

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report. 

A draft of this report was provided to the following directly involved parties:

• the student pilot, flight instructor and air traffic controller
• the aircraft operator
• Airservices Australia
• the Civil Aviation Safety Authority.

Submissions were received from:

• the aircraft operator
• Airservices Australia.

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through:  identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2024 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Executive summary

What happened

On 7 December 2023, an Agusta A109E helicopter was conducting a marine pilot transfer operation. While landing on the ship Tai Keystone, the aircraft struck a handrail resulting in substantial damage to the tail rotor and minor damage to the vessel.

What the ATSB found

The ATSB found that the handrail had not been removed during the preparation of the helicopter landing site. It was also found that the ship’s crew was using an older version of a checklist which did not require their removal. This item was however included in the latest version of the International Chamber of Shipping Guide to Helicopter/Ship Operations checklist current at the time of the occurrence. 

The ATSB also determined that the handrail would have been difficult for the helicopter pilot to detect as it had been painted in a colour which did not contrast with the colours used on the ship deck. This was not in accordance with the guidance for shipboard helicopter landing sites in the International Chamber of Shipping Guide to Helicopter/Ship Operations. Additionally, during the landing, the helicopter was not positioned correctly on the helicopter landing site. This resulted in the tail rotor being outside the obstacle free zone and striking the handrail.

It was also identified that the Civil Aviation Safety Authority Advisory Circular 139 Guidelines for heliports - design and operation did not include guidance material for the marking of objects, except for wind direction indicators, located on the helicopter landing site.

Finally, the Australian Maritime Safety Authority Marine Order 57 – Helicopter operations referenced an outdated version of the International Chamber of Shipping Guide to Helicopter/Ship Operations.

What has been done as a result

Taiwan Navigation Co. Ltd, have updated their helicopter/ship operation safety checklist to include the following checklist items:

• the deck party is aware that a landing is to be made
• the operating area is free of heavy spray or seas on deck
• the side rails and, where necessary, awnings, stanchions and other obstructions have been lowered or removed
• all personnel been warned to keep clear of rotors and exhausts
• the ship operator will now be notified of updates to the International Chamber of Shipping Guide to Helicopter/Ship Operations when new versions are published.

Jayrow Helicopters have amended their procedures to ensure that helicopter pilots are provided with visual representation of each individual vessel helicopter landing site prior to departure. They were also developing a new pilot checklist that included a requirement to ensure no obstacles existed in the helicopter landing area.

The Australian Maritime Safety Authority noted the reference to the outdated guide and will include this for correction in a planned review of Marine Order 57.

Safety message

It is the responsibility of the pilot in command to ensure that a landing area is safe. Where possible, helicopter pilots should attempt to gather as much information about the helicopter landing site (HLS) prior to departure and conduct an inspection of the intended landing area before commencing an approach to land. Photographs and obstacle maps of the HLS can be a valuable source of information to assist helicopter pilots with threat identification.

Objects that present a threat to a landing helicopter that are retractable, collapsible or removable should be painted in an appropriate colour to ensure they are visible if forgotten or missed. The use of reflective tape or lighting also increases the visibility of these objects.

Additionally, vessel operators should ensure their procedures and the landing area on the ship are aligned with the relevant guidance material.

The occurrence

On 6 December 2023 at 2015 local time, the merchant vessel Tai Keystone, departed Hay Point, Queensland for Tachibana, Japan. The vessel’s route passed through the Great Barrier Reef via the Hydrographers Passage and due to its size (over 70 m in length), the Tai Keystone required a marine pilot[1] to assist navigating this route.

The Tai Keystone departed Hay Point with the marine pilot on board and reached the start of the compulsory pilotage area for Hydrographers Passage at about 0100 on 7 December. The vessel completed the passage at about 0730 and the marine pilot was relieved of duty. As the marine pilot did not expect to depart the vessel for several hours they left the ship’s bridge to obtain rest in the sleeping quarters.

At about 0830, an Agusta A109E helicopter, registered VH-RUA, departed Mackay, Queensland with just the pilot onboard. The pilot planned to land on the Tai Keystone to retrieve the marine pilot and then proceed to another ship, to conduct a second marine pilot retrieval, before returning to Mackay Airport. 

The helicopter was flown north‑east from Mackay and at about 1012 the helicopter pilot attempted to establish communication with the Tai Keystone for the first landing however, this was unsuccessful. Another attempt to establish communication was successful at about 1027, 15 minutes prior to landing.

Due to slope landing limitations, the helicopter pilot requested information on the extent to which the vessel was rolling[2] and the master[3] of the ship advised it was between 3–5°. As this was at the helicopter operator’s limit of 5° for daylight operations, the helicopter pilot requested the marine pilot join the ship’s master on the bridge to give instructions to help reduce the ship’s roll.

The marine pilot arranged for the vessel’s heading to be changed to 340°, which reduced the roll to approximately 2°. The helicopter pilot was informed that the emergency crew was on standby, and that the master had given permission for the helicopter to land.

The helicopter pilot completed their pre-landing checks and, while at 300 ft on approach to the ship, conducted a visual inspection of the shipboard helicopter landing site (HLS).[4] They advised that, while they had not landed on this ship previously, this height was close enough to do an effective reconnaissance of the HLS. The pilot noted red manhole covers, where they would normally land the nose wheel, as the only obstacles inside the landing area. Having assessed that these did not present a threat as the helicopter could land clear of the manholes, they continued the approach.

At about 1042, the helicopter landed on the ship and as the wheels touched the deck, the tail rotor struck an upright handrail that was not identified by the pilot during the approach. The helicopter pilot reported hearing a shredding noise and an increase in the engine pitch before completing the emergency shutdown procedure.

The helicopter sustained substantial damage and was secured to the deck of the Tai Keystone, which then returned to Hay Point to assist with removal of the helicopter from the vessel.

Context

Helicopter Pilot

The pilot of the helicopter held a commercial pilot licence (helicopter) with a multi‑engine helicopter class rating. Their total flight experience at the time of the incident was 4,880 hours with 300.8 hours on the Agusta A109E and they had recently completed both a proficiency check and line check to a satisfactory standard. The helicopter pilot also held a current class 1 medical certificate.

Helicopter

The helicopter was an Agusta A109E, which was manufactured in 2001 and issued serial number 11129. It was registered in Australia in 2010 as VH-RUA and began operations with the operator in 2017. The Agusta A109E is a multi-engine helicopter with 2 Pratt & Whitney PW206-C engines driving a 4-blade main rotor and a 2-blade tail rotor.

The ATSB was provided aircraft flight data from the onboard spider track recording device. The data provided an updated aircraft position at a maximum of 15 second intervals. 

Vessel

The merchant vessel Tai Keystone was a bulk carrier with an overall length of 228.41 m, it was built in 2017 and provided the unique ship identifier number 9789843 by the International Marine Organisation (IMO). The vessel was operated by the Taiwan Navigation Co Ltd and registered under the Panama flag.

The vessel had several hatch-covers, one of which was used as a shipboard HLS when needed (Figure 1).

Figure 1: Exemplar vessel for reference

Image source: ATSB investigation MO-2016-003 annotated by the ATSB

Handrails

Handrails or stanchions[5] are used as an extension of the ladders installed to gain access to the shipboard HLS (Figure 2). The handrails are removable and usually stowed when the ship is underway. They are normally only installed once the helicopter has landed and removed prior to its departure. The handrails were painted yellow and were about 2.5 cm in diameter by 1 m tall. It was reported that these types of handrails were not considered to be a common feature on vessels.

The marine pilot on board the ship advised they instructed the vessel’s crew to remove the handrails before the helicopter arrived. This request occurred prior to the marine pilot going to the sleeping quarters and when they returned to the bridge, they did not confirm whether this action had been completed.

Figure 2: Starboard[6] handrails (removed at the time of the occurrence)

Image source: helicopter pilot in command

The helicopter pilot reported that, after exiting the helicopter, they observed the vessel’s starboard‑side handrails were removed. However, the port‑side handrails that were struck were still installed (Figure 3).

Figure 3: Handrail positions

Image source: helicopter pilot in command

The HLS was predominantly painted in green with a yellow circle and a white ‘H’. The vessel’s name was also painted in white in the HLS. There was a permanent yellow ladder (Figure 2) leading up to the HLS and yellow painted walkway lines leading to the ladder, on the deck of the ship (Figure 4).

Figure 4: Struck handrail and damaged tail rotor

Image source: helicopter pilot in command

Communication

Once the marine pilot joined the master on the bridge, they advised the helicopter pilot that:

• the wind was from 080° at 20 kt
• the ship was not pitching
• there was no sea spray
• emergency crews were on standby
• the helicopter had the master’s permission to land. 

No information on obstacles was passed to the helicopter pilot.

Helicopter approach

The helicopter pilot advised that they commenced their approach from behind the Tai Keystone on the port[7] side of the vessel as it provided a clear view of the vessel from their position on the right side of the helicopter.

The pilot reported that once the helicopter was turned to align with the HLS, which occurred after they completed their reconnaissance, the instrument panel obscured the undershoot area of the HLS, so they could only see the landing area and not the entire hatch cover. They further advised that, due to the position of the manhole covers, they ensured that during the landing, the nose wheel was slightly back on the ‘H’ on the HLS (Figure 5). It was reported by both the helicopter and marine pilots that it was common for the helicopter tail rotor to hang over the edge of the hatch to avoid other obstacles, such as pipes and vents.

The helicopter pilot also advised that at 300 ft, a narrow yellow pole was almost impossible to detect. In addition, the ladder leading to the poles was painted yellow, there was yellow on the hatch, and yellow lines on the edge of the landing hatch (the yellow walkway) (Figure 4). They advised yellow was a very common colour on a ship and, on this occasion, impeded detection of the port‑side handrails during the approach.

Figure 5: Tai Keystone's helicopter landing site viewed from the bridge

 Image source: helicopter pilot in command

Touchdown position

The Civil Aviation Safety Authority Advisory Circular 139 Guidelines for heliports – design and operation required that an HLS had a helicopter touchdown/positioning marking (TDPM) as follows:

The objective of touchdown/positioning marking (TDPM) is to provide visual cues which permit a helicopter to be placed in a specific position such that, when the pilot’s seat is above the marking, the undercarriage is within the load bearing area and all parts of the helicopter will be clear of any obstacles by a safe margin.

Where there was no limitation on the direction of touchdown/positioning, a touchdown/positioning circle (TDPC) should be used instead. The line width should be at least 1 m.

On this occasion, the helicopter was positioned with the pilot’s seat over the centre of the white ‘H’, rather than as required with the pilot’s seat above the yellow TDPC (Figure 5). 

Marine pilot transfer procedures

Helicopter procedures

The operator’s exposition provided the following information on a typical transfer procedure:

 …Descend to 500 ft for a recce[8] to confirm wind, obstructions and approach options. 

It also stated that this could be amended to suit the variables of weather, pilot experience, type of ship and whether it is day or night.

The exposition also stated that:

• The safety of the helicopter remains at all times the responsibility of the helicopter pilot in command…

• On arrival overhead or approaching each ship a reconnaissance (recce) should be flown. During this recce or circuit, a careful assessment must be made of the relative wind over the deck with particular attention paid to possible obstructions such as stanchions and cranes, etc… For some transfers, several orbits or an approach with overshoot may be required to obtain sufficient information.

• Pilots should exercise caution on final to look for seamen or deck hands who may be in a position on the deck to approach the landing hatch from behind. Look for ladders and/or handrails during the recce and on final. They will have good intention in trying to assist the marine pilot exiting the helicopter but are often over enthusiastic and unaware of the dangers associated with the tail rotor. Therefore, attempt to keep the tail clear of ladders leading to the hatch from the surrounding deck…

The operator advised they did not maintain a database of ships that they regularly worked with, nor did they require the ship operators to provide a copy of the HLS certification. However, prior to each transfer the ship’s master was required to complete a form designed to identify hazards. If any hazardous items were identified, they were to be photographed and the images added to the form. These forms were provided to pilots prior to departure.

The ship’s master completed this form and did not identify any hazards that increased risk for this vessel. Specifically, they advised there were no obstructions higher than 30 cm on the landing hatch.

Vessel procedures

The Hay Point port procedures required that the ship’s master complete a form to show that the ship complied with the Hay Point port procedures. This form was completed and signed by the ship’s master on 19 November 2023 and indicated that there were no obstructions higher than 30 cm on the landing hatch. The form also indicated that the ship would comply with the International Chamber of Shipping Guide to Helicopter/Ship Operations, as per Marine Order 57 (see the section titled International Chamber of Shipping Guide to Helicopter/Ship Operations).

The vessel’s crew completed a helicopter/ship operation safety checklist on 7 December at 0925, prior to the helicopter’s landing. The checklist revision date was 2017 and referenced the International Chamber of Shipping Guide to Helicopter/Ship Operations, for further guidance. This checklist did not include an item to remove handrails/stanchions.

International Chamber of Shipping Guide to Helicopter/Ship Operations

The International Chamber of Shipping Guide to Helicopter/Ship Operations, fifth edition was published in June 2021, the checklist provided in the fifth edition of the guide included:

• Side rails and, where necessary, awnings, stanchions and other obstructions have been lowered or removed.

The guide also included the following additional considerations for helicopter operating areas.

Chapter 4.3.1 General guidance on markings

The recommended colours of the markings reflect current international standards and best practices and promote a standardised approach to helicopter landing area markings. But as the colour of the main deck may vary from ship to ship, there is some discretion in the selection of deck paint schemes, the objective always being to ensure that the markings show up clearly against the surface of the ship and the operating background.

Chapter 4.5 Additional considerations for helicopter operating areas

- Any handrails that exceed the height limitations set out in section 4.1.2 are made retractable, collapsible or removable and do not obstruct access/exit routes. These handrails should be painted in a contrasting colour scheme and procedures should be in place to retract, collapse or remove them before the helicopter arrives. 

- Obstructions close to or inside the operating area, which may present a hazard to helicopter operations, need to be readily visible from the air and should be highlighted. Painting of obstructions should follow the scheme set out in Chapter 9 and Appendix E, as appropriate.

Chapter 9.5 Centreline/amidships helicopter landing/operating area plan included a procedure which should be followed when indicating obstructions on the operating area plan.

1.   Red and white stripes should be used to mark the location of notifiable objects in either the central clear zone or the obstacle free sector for the breadth of the ship deck…

      -  Objects in the central clear zone of height exceeding 2.5 cm; and

      - Objects around or outside the central clear zone but in the obstacle free sector described as the funnel of approach for the breadth of the ship’s deck of height exceeding 25 cm.

2.   Yellow should be used for marking the position of objects in the forward and aft limited obstacle sectors for the width of the ship’s deck to which the attention of the helicopter pilot should be drawn. 

The port‑side handrails were within the obstacle free sector (clear zone) (Figure 6). The clear zone is required to be free of obstacles that present a risk to the helicopter operation. 

Figure 6: Landing area terminology

Image source: Civil Aviation Authority UK Civil Aviation Publication 437

Civil Aviation Authority of United Kingdom, Civil Aviation Publication 437

The Civil Aviation Authority (CAA) of United Kingdom published Civil Aviation Publication 437 (CAP 437) Standards for offshore helicopter landing areas. This publication has become an accepted worldwide source of reference for assessing offshore helicopter landing areas.

The CAP 437 provides the same guidance as the International Chamber of Shipping guide for handrails detailed above.

Civil Aviation Safety Authority, Advisory Circular 139

The Australian Civil Aviation Safety Authority published Advisory Circular (AC) 139 Guidelines for heliports design and operation. The AC guidance stated there should be no objects greater than 25 cm or that present a threat to the safe operation of the helicopter on the HLS. However, it did not discuss removable objects, nor a colour to ensure they were visible if accidently left in place.

Australian Marine Safety Authority, Marine Order 57

The Australian Marine Safety Authority, Marine Order 57 specifically defined the International Chamber of Shipping (ICS) guide as the Guide to Helicopter/Ship Operations, fourth Edition (2008), published by Marisec Publications, London, on behalf of the ICS. The fifth edition of this guide was released in June 2021, however Marine Order 57 was not amended to reflect the latest updated/improved document. 

Safety analysis

The marine pilot advised that they detected the handrails installed on the helicopter landing site (HLS) and instructed a crew member to remove them prior to the helicopter arriving. The helicopter pilot also advised that only one set of handrails was in place when they landed. As such, it is possible that when the instruction was given to remove the handrails:

• one set of handrails was installed, and these were not removed, or
• 2 sets of handrails were installed, and only one was removed.

The ship’s crew were using an outdated version of the International Chamber of Shipping Guide to Helicopter/Ship Operations checklist, which did not include a specific check for handrails or stanchions. While the ATSB could not identify if the checklist had been completed prior to the marine pilot detecting the installed handrails, it is likely that if the vessel was using the most current version, which included a specific item to check for handrails and stanchions, it would have required a member of the vessel’s crew to actively check the handrails and consequently they would have been removed. 

The communication between the helicopter and vessel did not include information regarding obstacles, and because no obstacle information was passed to the helicopter pilot, they believed the HLS would be safe to land on. During the helicopter’s approach to the HLS, the helicopter pilot completed a reconnaissance at 300 ft, which provided an opportunity to identify the obstacle. However, as the handrails were an unusual method of accessing the HLS and due to their size, shape and colour, it is likely they would have been difficult to detect. Since the starboard‑side handrails were not installed, once the pilot aligned the helicopter with the final approach path to the landing site, there were no visual cues alerting them to the possibility that the port‑side handrails had not been removed.

The pilot of the helicopter stated they were aware of the red hatch cover obstacles inside the landing site and decided to avoid them by positioning the helicopter clear of the covers. Consequently, the aircraft was positioned with the pilot’s seat over the white ‘H’ instead of the yellow touchdown/positioning circle. This position put the tail rotor slightly outside the obstacle free sector and resulted in contact with the railing.

The International Chamber of Shipping guide provided guidance that removeable handrails should be painted in a contrasting colour scheme, however it did not identify what the colour should be contrasting with. The guide advised that:

• objects in the forward and aft limited obstacle sector should be painted yellow (the handrails were not in this zone)
• notifiable objects in the obstacle free sector exceeding 25 cm should be marked in red and white stripes.

However, despite the handrails being within the obstacle free sector, as they were removable, they were not notifiable objects. In addition, the HLS surface was painted green with yellow markings and, the environment surrounding the handrails, including the permanent ladder leading to the handrails, consisted of items which were also mostly painted in yellow. As such, the yellow handrails did not visually stand out to the helicopter pilot.

The helicopter operator’s exposition provided a warning for pilots relating to seamen installing the handrails prior to a helicopter landing. While the main concern was ensuring seamen did not enter the HLS, this indicated that handrails were a known threat. The helicopter pilots were not always provided with a visual representation of HLSs prior to departure. However, they did receive a form completed by the ship’s master which identified if obstacles were present. Often, the first time they saw the landing site was on arrival overhead the vessel, which limited the opportunity to assess possible threats. Despite this, because the handrails were not a notifiable object, it is unlikely that they would have been included in any guidance of the HLS.

The Civil Aviation Safety Authority published Advisory Circular (AC) 139 Guidelines for heliports ‑ design and operation however, when compared with the United Kingdom (UK) Civil Aviation Authority (CAA) Civil aviation publication (CAP) 437 Standards for Offshore Helicopter Landing Areas, it lacked guidance relating to the colour of obstacles inside the HLS clear zone. AC 139 did not encompass the most current guidance available.

As the Tai Keystone was using the guidance from the International Chamber of Shipping guide, despite it being an earlier version, the lack of information in AC 139 was not considered to have contributed to the incident.

The Australian Marine Safety Authority, Marine Order 57 specifically referenced the International Chamber of Shipping guide, however it referred to a superseded version. 

Findings

From the evidence available, the following findings are made with respect to the ground strike during a marine pilot transfer, involving an Agusta A109, VH-RUA and ship Tai Keystone, about 240 km north‑east of Mackay Airport, Queensland on 7 December 2023.

Contributing factors

• During preparation for the helicopter’s arrival, the port side handrails were not removed.
• Prior to the approach, the pilot did not detect the obstacle on the helicopter landing site.
• During the landing, the pilot's seat was not positioned over the touchdown/positioning circle resulting in the tail rotor being outside the obstacle clear sector and striking the handrail.
• An earlier version of the helicopter operations checklist was used by the crew of the Tai Keystone. That checklist did not include a requirement, present in the version current at the time of the incident, to remove handrails or stanchions from the helicopter landing site. [Safety issue]
• The colour of the handrails did not comply with the guidance material provided by the International Chamber of Shipping guide, which increased the difficulty for the helicopter pilot to detect them.

Other factors that increased risk

• The Civil Aviation Safety Authority Advisory Circular 139 Guidelines for heliports – design and operation did not include guidance material for the marking of objects, except for wind direction indicators, located on the helicopter landing site.
• The Australia Maritime Safety Authority Marine Order 57 – Helicopter operations, defined the International Chamber of Shipping guide as the fourth edition published in 2008. This was not the latest improved/updated version of the guidance material.

Safety issues and actions

Helicopter operations checklist

Safety issue number: AO-2023-059-SI-01 

Safety issue description: An earlier version of the helicopter operations checklist was used by the crew of the Tai Keystone. That checklist did not include a requirement, present in the version current at the time of the incident, to remove handrails or stanchions from the helicopter landing site. 

Safety action not associated with an identified safety issue

Proactive safety action taken by Jayrow Helicopters

Following this occurrence, Jayrow Helicopters amended their procedures to ensure that helicopter pilots were provided with images of each individual vessel helicopter landing site prior to departure. They were also developing a new pilot checklist that included a requirement to ensure no obstacles existed within the helicopter landing area.

Proactive safety action taken by Australian Maritime Safety Authority

AMSA noted the reference in Marine Order 57 to the 2008 edition of International Chamber of Shipping Guide, not the updated edition 2021. They advised that this outdated information would be noted for correction in its planned review of Marine Order 57.

Glossary

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• helicopter pilot and operator
• marine pilot
• Tai Keystone Master
• spider tracks
• Australian Maritime Safety Authority

References

1. International Chamber of Shipping Guide to Helicopter/Ship Operations (5^th ed). (2021). London: Marisec Publications
2. Australian Reef Pilots Guide. (2013). Australia
3. Port Procedures and Information for Shipping – Port of Hay Point. (2017). Australia: Queensland Government
4. Marine Order 57 – Helicopter OperationsF2016L00496. (2019). Australia: Australian Maritime Safety Authority
5. Civil Aviation Publication 437 - Standards for offshore helicopter landing areas (9^th ed). (2023) United Kingdom: Civil Aviation Authority
6. Civil Aviation Safety Authority – guidelines for helicopters – design and operation Version 2.0. (2023) Australia: Civil Aviation Safety Authority
7. Australian Transport Safety Bureau. (2017). Contact with navigation buoy, Navios Northern Star, Torres Strait, Qld on 15 March 2016. MO-2016-003

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report. 

A draft of this report was provided to the following directly involved parties:

• helicopter pilot
• helicopter operator
• marine pilot
• vessel operator
• Tai Keystone Master
• Civil Aviation Safety Authority
• Australian Maritime Safety Authority 

Submissions were received from:

• the vessel operator
• Civil Aviation Safety Authority

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through:  identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2024 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Commonwealth Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this report is licensed under a Creative Commons Attribution 4.0 International licence. The CC BY 4.0 licence enables you to distribute, remix, adapt, and build upon our material in any medium or format, so long as attribution is given to the Australian Transport Safety Bureau.  Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Executive summary

What happened

On 31 August 2022, an Ayres Corporation S2R-T15, registered VH-IWI, was conducting aerial application operations. Around 100 m into a take-off roll, the pilot heard a bang as the left wing hit the ground and the aircraft performed a ground loop. No injuries were sustained.

Inspection revealed that the left main landing gear shock assembly had failed, with the left main landing gear folding outwards and contacting the bottom of the wing.

What the ATSB found

The ATSB examination identified that the lower tube of the left shock strut assembly failed at a fatigue crack, which led to the collapse of the left main landing gear and the aircraft wing to strike the ground. It is very likely that this lower tube was a part that Thrush Aircraft had instructed owner/operators to replace or modify in 1994 in accordance with a service bulletin. The reason the part was not replaced or modified was not identified.

Safety message

Manufacturers issue service bulletins to inform owners and operators about critical and useful information on aircraft safety, maintenance, or product improvement. The ATSB strongly encourages compliance with service bulletins pertaining to aircraft safety.

Additionally, on acquisition of an aircraft, it is important to review maintenance documentation to determine whether all the appropriate manufacturer issued instructions have been addressed.

 

The investigation

Decisions regarding the scope of an investigation are based on many factors, including the level of safety benefit likely to be obtained from an investigation and the associated resources required. For this occurrence, a limited-scope investigation was conducted in order to produce a short investigation report, and allow for greater industry awareness of findings that affect safety and potential learning opportunities.

The occurrence

On 31 August 2022, an Ayres Corporation S2R-T15, registered VH-IWI, was conducting aerial application operations from Trangie Airport. The pilot was the only person on board.

Three application flights were scheduled for the day, and after performing the daily aircraft inspection, the pilot commenced the first flight at around 0800 local time. Once the first flight was complete, the pilot obtained fuel and chemical, and taxied back to the airstrip to commence the second flight. The aircraft was around 100 m into the take-off roll when the left wing struck the ground, resulting in the pilot’s view being obstructed with chemical, and the aircraft started to rotate. In an attempt to stop the aircraft, the pilot applied reverse thrust. After completing a ground loop, the aircraft came to rest near the left edge of the runway. No injuries were sustained.

Initial inspection revealed that the left main landing gear shock assembly had failed, with the left main landing gear folding outwards and contacting the bottom of the wing.
 

Context

Operational and maintenance history

VH-IWI was manufactured by the Ayres Corporation in 1980 and first registered in Australia on the 24 December that year. The aircraft was powered by a Pratt & Whitney PT6A -15AG engine. It had accumulated 14,474.5 hours total time in service. The last maintenance took place 2 days prior to the occurrence and the right landing gear was replaced in 2012.

The Ayres Corporation[1] had issued 2 service bulletins associated with the main landing gear shock strut assembly.[2] The first, SB-AG-31,[3] was issued in 1992 in response to failures that occurred in the upper tube. This service bulletin described a modification to strengthen the upper tube, adding 4 rosette welds to the existing 2 rosette welds.[4] An entry in the aircraft maintenance logbook indicated that shock struts were welded to comply with SB-AG-31.

The second service bulletin, SB-AG-36,[5] was issued in 1994 in response to failures that occurred in the lower tube and included strengthening the lower tube. SB-AG-36 described 5 methods to comply with the bulletin:

• (1) replace shock assembly with P/N 50116-29 (new)
• (2) replace shock assembly with P/N 50116-28F1 (re-worked)
• (3) replace lower tube P/N 50116-12 with P/N 50116-12F (modified)
• (4) replace lower tube P/N 50116-12 with P/N 50116-30 (new design)    
• (5) modify old lower tube P/N 50116-12

Option (5) described the removal of a plug from the top of the tube, removal of a 0.12” (3.0 mm) thick and 1 3/8” (34.9 mm) long reinforcing tube, insertion and welding (including rosette welds) of a 0.312” (7.9 mm) thick and 4.25” (108.0 mm) long reinforcing tube P/N 50116-100, and attachment of a plug by welding. No logbook record indicating compliance with SB-AG-36 was found. The current maintainer stated they were performing maintenance under the assumption that all previous maintenance had been performed according to the manufacturer’s instructions. The reason the lower tube was not replaced or modified when the service bulletin was issued was not identified.

The operator of VH-IWI acquired the aircraft in 2018. The maintainer commenced maintaining the aircraft in the 12 months leading up to the occurrence. They were not the maintainer of the aircraft when either SB-AG-31 or SB-AG-36 were issued.

ATSB technical examination

Examination of the damaged main landing gear shock strut assembly was conducted at the ATSB’s technical facilities. The overall condition of the assembly was aged, and the rubber shock biscuits were cracked (Figure 1).

Figure 1: Left main landing gear shock strut assembly

Schematic and photo showing the main landing gear shock struct assembly with components labelled. The assembly was dirty and the shock biscuit exhibited cracks.

Source: Thrush Aircraft (schematic), ATSB (photo and annotations)

The grease between the upper and lower tube was discoloured; however, there was fresh blue grease around the lubricator and within the lower tube near the point of fracture. A substantial amount of new grease appeared to have migrated out of the lower tube during the occurrence.

The left shock strut fractured at the hole where the lower steel tube attached to the slider plate
(Figure 1). This allowed the bottom portion of the lower tube to separate from the remaining shock assembly. The fracture was consistent with fatigue cracking, followed by unstable crack growth and ductile overstress (Figure 2).

Figure 2: Fractured lower tube exhibiting characteristics of fatigue fracture followed by overstress

Fracture surface exhibiting characteristic of fatigue cracking followed by overstress.

Source: ATSB

The construction of the fractured lower tube consisted of a steel tube, around 3 mm thick and 400 mm long, reinforced inside with a smaller diameter section of tube, around 3mm thick and 35 mm long, over the region of the through-hole. The reinforcing tube was welded to the lower tube at the top end. There was no end cap on the lower tube, which was present on a more recently-manufactured lower tube. There were no rosette welds connecting the lower tube and the reinforcing tube. The upper tube of the left shock strut assembly was also examined; there were 6 rosette welds present on the upper tube.

There was a handwritten marking on the side of the lower tube (Figure 3) which was identified as the characters ‘50116T012 25[?]’, with an indistinct character at the end.

Figure 3: Marker writing on the lower tube

Writing on the lower tube written in black marker. The characters are 50116T012 25[?].

Source: ATSB

Advice from Thrush Aircraft

When asked about the writing on lower tube Thrush Aircraft informed the ATSB that first 5 characters represented a drawing number,[6] the 3 numbers to the right of the ‘T’ identified the component on that drawing. The drawing number, together with the component identifier, was considered the ‘part number’ and these numbers, 50116-012, were consistent with the designation of the pre-1994 lower tube design. Thrush Aircraft suggested the final 3 digits might be an employee or serial number.

A representative from Thrush Aircraft concluded that, based on the available evidence, the failure was consistent with the failures that prompted SB-AG-36.

Safety analysis

The ATSB examination identified that the lower tube of the left shock strut assembly failed at a fatigue crack. The crack had initiated from the hole where the lower tube attached to the slider plate and propagated around the circumference of the tube. The final fracture most likely took place early in the take-off roll which led to the collapse of the left landing gear and the aircraft wing striking the ground.

The dimensions of the reinforcing tube[7] and the writing on the side of the part were most consistent with the original part, noting that there was no plug. This part was to be replaced or modified to comply with SB-AG-36. It was not possible to determine the exact age of the lower tube. It is very likely that this lower tube was manufactured prior to 1994 and would need to have been replaced or modified to comply with the service bulletin.

The construction of the upper tube was consistent with SB-AG-31, which was issued 2 years before SB-AG-36.

Findings

ATSB investigation report findings focus on safety factors (that is, events and conditions that increase risk). Safety factors include ‘contributing factors’ and ‘other factors that increased risk’ (that is, factors that did not meet the definition of a contributing factor for this occurrence but were still considered important to include in the report for the purpose of increasing awareness and enhancing safety). In addition, ‘other findings’ may be included to provide important information about topics other than safety factors.  These findings should not be read as apportioning blame or liability to any particular organisation or individual.

From the evidence available, the following findings are made with respect to the ground strike involving Ayres Corporation S2R-T15, registration VH-IWI at Trangie, New South Wales on 31 August 2022.

Contributing factors

• A fatigue crack initiated in the lower steel tube of the left shock assembly, located at the hole where the lower tube connected to the slider plate. The fatigue crack grew until there was a final overstress failure of the lower tube during the take-off roll.
• For reasons not identified, it was highly likely that the lower tube of the left landing gear shock assembly was not replaced or modified to comply with SB-AG-36, which was issued to prevent similar failures.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• pilot of the occurrence flight
• Civil Aviation Safety Authority
• Thrush Aircraft
• maintenance organisation for VH-IWI

References

Main Landing Gear Shock Strut Inspection and Repair, Service Bulletin: SB-AG-31, Ayres Corporation, 3 November 1992. [Online]. Available: https://thrushaircraft.com/support/technical-publications/Service%20Bulletins/sb-ag-31%20MAIN%20LANDING%20GEAR%20SHOCK%20STRUT%20INSPECTION%20AND%20REPAIR.pdf [Accessed: 18 November 2022].

Main Landing Gear Shock Strut Modification, Service Bulletin: SB-AG-36, Ayres Corporation, 25 March 1994. [Online]. Available: https://thrushaircraft.com/support/technical-publications/Service%20Bulletins/sb-ag-36%20MAIN%20LANDING%20GEAR%20SHOCK%20STRUT%20MODIFICATION.pdf. [Accessed: 18 November 2022].

Maintenance Manual Model S2R-T15 Model S2R-T34, Serial Numbers T15-020 & Subsequent Numbers T34-091 & Subsequent Numbers, Thrush Aircraft Inc., 25 October 1990. Revised: 24 July 1991.

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the following directly involved parties:

• pilot of the occurrence flight
• maintenance organisation for VH-IWI
• Civil Aviation Safety Authority
• Thrush Aircraft

No submissions were received.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2023 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

[1]     In 2003, Ayres Corporation’s assets were purchased by Thrush Aircraft, the current producer of the aircraft.

[2]     The main landing gear shock strut reduces the landing loads transmitted from the landing gear to the fuselage.

[3]     Main Landing Gear Shock Strut Inspection and Repair, Service Bulletin: SB-AG-31, Ayres Corporation, 3 November 1992. [Online]. Available: https://thrushaircraft.com/support/technical-publications/Service%20Bul…. [Accessed: 18 November 2022].

[4]     A rosette weld, also known as a plug weld, is a process that fuses two metals together by making a weld inside small circular holes.

[5]     Main Landing Gear Shock Strut Modification, Service Bulletin: SB-AG-36, Ayres Corporation, 25 March 1994. [Online]. Available: https://thrushaircraft.com/support/technical-publications/Service%20Bul…. [Accessed: 18 November 2022].

^[6]     The drawing number together with the component identifier was considered the ‘part number’.

[7]     The reinforcing tube was around 3mm thick and 35 mm long, while the pre-1994 reinforming was described as 0.12” (3.0 mm) thick and 1 3/8” (34.9 mm) long.