Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 1 May 2022, at about 1558 local time, the pilot of a Quest Kodiak 100 departed Orange Airport, on a private flight, to Mittagong, New South Wales.
At 1620, while cruising at 9,500 ft, the pilot observed the ‘reservoir fuel’ warning light illuminate. They immediately put the fuel pump on, checked both fuel cocks were on, checked the fuel quantity and balance and reduced the power to preserve fuel. Shortly after, the pilot then received a fuel starvation imminent warning followed by low fuel pressure warnings.
At the time of the warnings, the aircraft was overflying a remote sandstone escarpment region that contained deep gorges and large cliff lines, and was approximately 30 NM (56 km) away from any open land. Due to limited options to conduct a precautionary landing, the pilot continued to cycle the fuel pump, further reduced the power and turned towards an area suitable for a forced landing. During this time, the pilot heard multiple loud bangs.
The pilot continued to cycle the fuel pump and after a few minutes the fuel messages stopped. When the pilot was satisfied that the engine had enough fuel, they tracked direct to Mittagong and landed the aircraft safely at about 1651.
Engineering inspection
Following the incident, the pilot conducted a post-flight inspection and observed the upper skin on the right wing had crumpled and collapsed. To relieve the vacuum in the wing, the pilot attempted to open the fuel cap by forcing a piece of laminate under the cap. After partly opening the cap, a large amount of air was sucked into the tank and the upper skin of the wing popped back out once the pressure was relieved. However, there was still a large depression of about 11 mm (Figure 1).
Figure 1: Fuel tank depression on the right wing
Source: The pilot, annotated by ATSB
An engineering inspection of the right wing revealed the ribs and stringers had failed and the wing was no longer airworthy. Further inspection of the fuel tank vent line inlet recess also revealed mud wasp nests deep inside the vent lines for both wings, which were unable to be inspected or seen visually during the pre-flight inspection (Figure 2 and Figure 3).
Figure 2: Fuel tank vent line NACA inlet recess on the wing
Source: The pilot
Figure 3: Diagram of the fuel tank vent line within the wing
Source: Pilot, annotated by ATSB
Fuel tank vents are used to ensure the pressure inside the tank is maintained when fuel is being used by the engine. If a fuel tank vent becomes blocked while fuel is being pumped out, it will create a vacuum due to the inability of air not being vented in to replace the fuel, which can cause the tank to collapse.
Pilot comments
The pilot advised:
The aircraft was parked in a hangar and had been flown on the Thursday and Friday prior to the occurrence. No abnormalities during those flights were detected.
They would typically only fill the fuel tanks halfway, but while at Orange they had filled them up to the top. They postulated that the vacuum occurred in this flight because there was less air in the tank compared to when the tanks are half full.
Safety action
As a result of this occurrence, the pilot advised the ATSB that they made a protective plug for the fuel tank vent lines to prevent wasps from building nests (Figure 4). The plug consists of a clear plastic tube that is long enough to be inserted into the vent line, which can be used to detect an obstruction in the line if resistance is felt. At the end of the tube is a masonry plug with a screw to seal the tube and streamers to ensure the plug is not missed during the pre-flight inspection. In addition to this, the pilot has also informed other operators at the aerodrome of the potential hazard.
Figure 4: Devised plug to protect the vent line inlet recess
Source: Pilot
Safety message
Blocked, or even partially blocked, pitot tubes and fuel tank vents can compromise the safety of the flight. Wasps can begin to build a nest rapidly and significantly block a fuel vent line or pitot tube within 30 minutes. Regardless of whether an aircraft has a short turn-around time or is parked overnight, protective covers and screens should be used on both fuel vent lines, fuel caps and pitot tubes. In addition to visually inspecting pitot tubes during pre-flight inspections, pilots should also inspect fuel vent lines. Moreover, operators and aerodrome personnel should monitor and remove any wasp nest sites in the general area of where the aircraft is stored and maintained to further reduce the risk.
For further information on wasp nest infestations please refer to the CASA Airworthiness Bulletin AWB-02-052.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On the morning of 1 December 2021, a flight instructor was preparing for a proficiency check flight in a Diamond Aircraft Industries DA-40 aircraft at Moorabbin Airport, Victoria. While completing the daily inspection of the aircraft, the instructor identified an anomaly with one of the propellor blades. The painted surface surrounding the leading edge of the blade had cracked. In addition, an associated portion of the adhesively bonded metallic strip had partially detached from the blade body, approximately 5 cm from the propellor blade tip.
The instructor notified another more senior company pilot (also an instructor) of the defect. However, while discussing the problem, assurance was provided that company engineering was aware of the problem and that the aircraft was considered airworthy.
Preparations for the flight were subsequently completed. The instructor, along with the assessment pilot, departed Moorabbin Airport in the Diamond DA-40 for the proficiency check flight. About 20 minutes into the flight, and while operating in the designated training area, a metallic ‘ping’ was heard by both pilots along with the detection of an airframe vibration (that lasted 1 to 2 seconds). The instructor recalled no abnormality with the engine indications or flight controls. The proficiency check flight proceeded without further issue and concluded approximately 60 minutes later.
After the return landing at Moorabbin Airport, and during the post-flight inspection of the aircraft, the flight instructor identified damage to the previously inspected propellor blade (Figure 1). The bonded metallic erosion strip from the leading edge of the blade had detached and fractured.
Figure 1: The damaged propellor blade showing a fractured erosion strip along the leading edge (left) and impact damage to the leading edge (right)
Source: Operator
Operator’s investigation
The operator removed the propeller and submitted it to an overhaul facility for examination and repair. The engineering report identified that the propellor blade had sustained impact damage to the composite blade structure in the region of the partially missing metallic strip. The report concluded that the pre-existing impact damage was from runway debris which had compromised the adhesive bonding of the metallic strip, leading to its eventual failure.
Operator’s safety action
The operator’s investigation of this occurrence identified that, although the flight instructor had identified then reported the propellor damage to a senior company pilot, a communication error between the parties led to confusion regarding the nature of the defect. As a result, on 10 December 2021, the operator issued an advisory notice to their pilots stating:
Crew, where possible and safe to do so, are to use their phones to take photos of any defects/concerns during an aircraft inspection.
All concerns and supporting evidence are to be presented to the HAAMC or their delegate.
Composite propellers tap tests are now conducted by the HAAMC and/or their delegate at the end of each flying day across the Diamond fleet.
Safety message
This incident serves as a reminder to pilots of the importance of contacting appropriate maintenance engineering personnel if a defect is found during pre- or post-flight inspections. In this situation, although a propellor defect was identified that affected the airworthiness of the aircraft, company engineering personnel were not made aware of the damage. An inspection by a licensed engineer would have provided an opportunity to inspect and further assess to then make an appropriate decision regarding the seriousness of the damage.
Pilots, operators, and maintainers should note that it is a civil aviation regulatory requirement for all aircraft defects, whether major or minor, to be endorsed on Part 2 of the maintenance release. The maintenance release is a document considered central to the safe operation of an aircraft. The aircraft must not be flown if the defect or damage is assessed as major, and, if the defective/damaged item is required for the intended flight. The aircraft maintenance release ceases to be valid until such a defect is rectified.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 16 March 2022, at about 1025 local time, a Cessna 172 RG was on approach to Gold Coast Airport, Queensland. The pilot was conducting a solo navigation training exercise.
As the aircraft approached the circuit area, the pilot actioned the before-landing checks, moving the fuel selector from the RIGHT to BOTH indent. Shortly after, the engine stopped. The pilot assessed that the aircraft was not in a position to glide to the runway and prepared the aircraft to conduct a forced landing onto a beach. They made a MAYDAY call on the Gold Coast Tower frequency.
An instructor from the same flying school, flying at the time, advised the pilot to ‘check the fuel selector’. The pilot adjusted the position of the selector and felt it click into the BOTH indent and the engine subsequently restarted. The pilot subsequently conducted a normal circuit and landed at Gold Coast Airport.
Maintenance actions
The aircraft’s fuel system was inspected by a licenced aircraft maintenance engineer and no faults were found.
Fuel system
The Cessna 172 RG has an integral fuel tank in both the left and right wing. Fuel is gravity fed to a four-way selector valve, then through a strainer to the engine-driven fuel pump and on to the carburettor. The fuel selector allows fuel to be fed from the left tank, right tank, both fuel tanks, or to be selected to OFF.
The pilot’s operating handbook (POH) stated:
The fuel selector valve should be in the BOTH position for take-off, climb, descent, landing, and maneuvers that involve prolonged slips or skids. Operation from either LEFT or RIGHT tank is reserved for level cruising flight only.
Operator’s investigation
Cessna 172 RG POH top-of-descent and before-landing checklists required the fuel selector valve be selected to BOTH. However, the operator’s internal investigation into the incident identified that neither its top-of-descent nor before-landing checklist accurately reflected this requirement.
The operator conducted a survey of its staff and students and identified that, while the majority were aware of the requirement to ensure the fuel selector was selected to BOTH at the top of descent, a small minority changed tanks as part of the before-landing checklist.
Safety action
As a result of this incident the operator has:
held a staff discussion to discuss the incident and standardise procedures based on the POH
raised a safety bulletin to highlight the issue and the dangers of changing fuel tanks at low altitudes
reviewed and updated the quick reference handbook and abbreviated checklist to follow the manufacturer’s POH
briefed all students as part of their pre-flight briefings to ensure awareness of following correct procedures.
Safety message
The ATSB continues to receive reports of engine failures due to fuel starvation. Effective fuel management during flight along with knowledge of the aircraft’s fuel system and proficiency in its use will ensure fuel is continuously supplied to the engine. The ATSB publication, Avoidable Accidents No. 5 - Starved and exhausted: Fuel management aviation accidents (AR-2011-112), is available from the ATSB website.
Operators are advised to ensure their operating procedures and checklist closely align with the aircraft manufacturer’s published materials. This will ensure flight crews consistently operate the aircraft in a method appropriate for the aircraft type.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence summary
Mode of transport
Aviation
Occurrence ID
AB-2022-001
Occurrence date
16/03/2022
Location
Gold Coast Airport
State
Queensland
Occurrence class
Incident
Aviation occurrence category
Fuel starvation
Highest injury level
None
Brief release date
01/07/2022
Aircraft details
Manufacturer
Cessna Aircraft Company
Model
172 RG
Sector
Piston
Operation type
Part 141 Recreational, private and commercial pilot flight training
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 13 November 2021, a Socata TB-20 Trinidad aircraft departed Jandakot Airport, Western Australia at about 1510 local time, for a private flight with two people on board. The flight was intended to be a 30-minute flight along the coast, at an altitude of no more than 1,500 ft.
About 15 minutes after take-off, the pilot noticed the engine was running ‘rough’. Believing it similar to a previous experience of vapour lock, the pilot began the relevant procedure by turning on the electric fuel pump and switching fuel tanks. This alleviated the rough running, however the engine continued to feel ‘different than normal’, so the pilot turned to return to Jandakot. About 2 minutes later, the rough running returned and shortly after the aircraft’s engine lost power. The aircraft was at 1,000 ft, about 1 km offshore.
The pilot assessed that the likelihood of a successful landing inland (past the sand dunes) was remote due to the aircraft’s altitude and position. The beach was being heavily used by the public, so the pilot decided to ditch in the water, as close to the shore as possible, and away from swimmers. The pilot radioed Perth air traffic control to notify them of the engine failure and intent to commence a ditching. The pilot manoeuvred to flare and touch down at 65—70 kt, which they judged to be the slowest safe approach speed, with landing gear retracted.
A forced landing was conducted approximately 50 m from the shore. The pilot and passenger sustained no injuries during the ditching and evacuation from the aircraft. The aircraft initially sustained cracks to the fuselage and was subsequently destroyed by wave action and salvage activities.
Figure 1: Aircraft wreckage
Source: Pilot of the aircraft
Pilot comments
The pilot attributed the successful outcome to their familiarity with the area and mental preparation, having previously considered the options available in a situation such as this. They also noted that prior research and discussion with other pilots gave them an understanding of how to minimise impact forces and the risk of becoming inverted during ditching.
Safety message
When experiencing a rough running engine, pilots should focus on flying the aircraft and continually assess landing options available in case of a complete engine failure during a turnback. Focus mainly on the arc where you would be able to land if the engine had fully failed — this is the current landing option. CASA recommends that scanning the environment should take 85% of the time available, 10% on checking aircraft attitude including lookout, and 5% of the time scanning of the altitude and airspeed indications.[1]
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 13 October 2021, at about 1400 local time, the pilot of a Robinson R44 helicopter was conducting a private flight from Tyagarah New South Wales to Rules Beach Queensland via Hervey Bay Queensland to re-fuel. After landing at Hervey Bay aerodrome, the pilot attached the fuel static cable[1] from the fuel bowser to the helicopter skid prior to commencement of refuelling (Figure 1). The pilot then became aware the fuel bowser was not serviceable and returned to the helicopter to plan the next stage of the flight to Rules Beach. A current NOTAM[2] had been issued at the aerodrome stating, ‘Avgas not available’.
The pilot then started the engine and became airborne. As the helicopter taxied prior to departure, the pilot was focused on another aircraft landing on the runway and then reported hearing a loud bang. The pilot banked the helicopter to the right and noticed the fuel static cable on the ground. The pilot reported there was no effect on flight and departed for Rules Beach. The pilot called the re-fueller en route to advise of the incident. The re-fueller informed the pilot that the fuel static cable was found in multiple pieces across the fuel facility apron and nearby taxiway. After landing at Rules Beach, the pilot inspected the helicopter and discovered minor damage to the tail boom, the tail rotor and main rotor which had made contact with the fuel static cable (Figure 2).
Figure 1: Fuel static cable attachment point
Source: Operator
Figure 2: Damage to main and tail rotors
Source: Operator
Safety message
This incident highlights the importance of ensuring that all pre-flight checks and procedures are carried out systematically as detailed in the flight manual. If interrupted, it is best practice to start again from the beginning to ensure that nothing is missed.
Pilots detecting sounds or control inputs that are not associated with normal aircraft operations, in particular during the critical phases of flight, should land and complete a thorough inspection of the aircraft as soon as it is safe and practical to do so.
The incident also highlights the importance for pilots to review all NOTAMs relevant to the planned flight.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
The occurrence
On 24 November 2021, the pilot of a Cirrus SR22 aircraft conducted a business flight from Northern Peninsula to Darnley Island (Erub), Queensland, with one passenger on board. The flight was conducted under the visual flight rules[1] and in visual meteorological conditions.[2]
At 0913 local time, the aircraft joined the downwind leg of the circuit for runway 10 at Darnley Island. The pilot reported conducting a stabilised approach. Once aligned with the runway, the pilot reduced the airspeed to about 3 kt slower than normal, to compensate for encountering less headwind than anticipated.
The aircraft landed long and ballooned,[3] touching down about 100 m beyond the runway threshold. The pilot initially assessed that there was still sufficient runway remaining to stop. However, when the nose wheel contacted the runway, it started to ‘wobble’. In response, the pilot pulled back on the elevator control to lift weight off the nose wheel and reduced pressure on the brakes. The pilot then realised the end of the runway was approaching and applied full braking, and the wheel wobble resumed.
The aircraft overran the runway and rolled down a steep embankment beyond the eastern threshold. The aircraft flipped over, coming to rest inverted (Figure 1). The pilot sustained minor injuries, and the passenger sustained serious injuries. Both were wearing the fitted four-point harness. The aircraft was substantially damaged.
Figure 1: Darnley Island aerodrome and accident site
Source: Babcock Aviation & Critical Services
Pilot qualifications and experience
The pilot was appropriately qualified for the flight and held a private pilot licence (aeroplane). The pilot’s aeronautical experience totalled nearly 5,000 hours, including about 1,600 hours in SR22 aircraft. The pilot had landed at Darnley Island 17 times previously, 5 of which were in the accident aircraft.
Darnley Island aerodrome
The runway on Darnley Island is 528 m long, 18 m wide, has a 2% slope down in the landing direction and lies 220 ft above mean sea level.
Airport reporting officer comments
The airport reporting officer (ARO) was at the aerodrome at the time of the accident and assisted in extricating the pilot and passenger from the aircraft. The ARO commented that there was no wind at the time and the windsock was drooping down. The ARO observed the aircraft touch down long and the nose wheel ‘wobbling all over the place’.
Nose wheel wobble
The pilot reported that the nose wheel wobble previously occurred on about 1 in 10 landings in the aircraft and had been investigated by aircraft maintainers. The recommended action in response to the wobble was to pull back on the elevator control and stop braking, then release back pressure and recommence braking. In this occurrence, the pilot performed those actions but in doing so, was distracted from initiating a go-around. The pilot also assessed that when braking heavily, the wobble had contributed to reduced braking effectiveness.
Pre-flight planning
Based on the area forecast, the pilot expected, and planned for, an easterly wind of 7–15 kt. The pilot calculated the aircraft’s weight and balance to be in the middle of the operating envelope. The aircraft landing distance charts did not specify a required runway length for the calculated landing weight, so the pilot used the closest (higher) available weight. Based on nil wind and a landing weight 226 kg heavier than the actual landing weight, the landing distance required was 378 m. This reduced to 340 m with a 15 kt headwind. Factoring in the 2% downslope increased the landing distance required to 524 m (with a 15 kt headwind). The pilot used this figure for planning, having assessed the wind would likely be stronger than forecast based on previous experience with the local conditions. The pilot therefore anticipated that with a stronger headwind and lighter landing weight than used for planning, there would be a safe margin between landing distance available and required.
Density altitude
The pilot reported the conditions at the time of the accident included an easterly wind of about 7 kt and visibility greater than 10 km. The nearest Bureau of Meteorology weather station was at Coconut (Poruma) Island, 89 km to the south-east, where the temperature at 0900 was 32 °C and the atmospheric pressure 1,009 hPa at sea level.
Assuming the conditions at Darnley Island were similar to Coconut Island, the pressure altitude at the aerodrome was about 340 ft above mean sea level and the density altitude about 2,380 ft. Effects of increased density altitude include increased landing roll distance and reduced performance in the event of a go-around.
Runway end safety areas for aircraft landing areas
Darnley Island aerodrome was uncertified and unregistered. Aerodromes that have not been approved to the regulated requirements are referred to as aircraft landing areas (ALA). An ALA is not required to comply with any aerodrome standards, and it is a pilot’s responsibility to determine the aerodrome’s suitability for the intended flight.
The Civil Aviation Safety Authority’s Civil Aviation Advisory Publication 92–1
, provides guidance for pilots operating at ALAs and considerations for ALA owners regarding obstacle clearance proximal to the runway. The publication does not include guidelines regarding an overrun area beyond the runway ends. In this occurrence, the steep embankment at the eastern end of the runway increased the risk of aircraft damage and occupant injury in the event of a runway overrun. There was also an escarpment beyond the runway’s western end.
Previous accident
In 1993, a Piper PA-23 aircraft overran the western end of the runway at Darnley Island (ATSB investigation 199303915). The pilot initiated a ground loop to stop the aircraft falling down the 50 ft escarpment beyond the western end of the runway strip.
Safety message
Pre-flight preparation includes understanding the destination aerodrome and environmental conditions and establishing a plan to manage identified hazards. The United States Federal Aviation Administration’s Advisory Circular 91-79A Mitigating the risks of a runway overrun upon landing listed the following hazards associated with runway overruns:
unstabilised approach
high airport elevation or high-density altitude, resulting in increased groundspeed
excessive airspeed or height over the runway threshold
airplane landing weight
landing beyond the touchdown point
downhill runway slope
delayed use of deceleration devices
landing with a tailwind
a wet or contaminated runway.
The circular recommends that once the actual landing distance is determined – taking into consideration the compound effects of multiple factors – a minimum 15% safety margin should be added.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 28 October 2021 at about 1550 local time, an AgustaWestland AW139 helicopter was conducting a landing at The Alfred hospital helipad, with two crew on board. The crew approached the helipad from the west, using a steep approach profile aligned with Commercial Road.
During the approach, a pedestrian walking along Commercial Road, about 50 m west of the helipad, was blown over by rotor wash from the helicopter which resulted in serious injuries. The pedestrian was taken to The Alfred hospital for treatment.
The helicopter crew were unaware that downwash from the landing had resulted in any injury to the pedestrian.
The Alfred helicopter landing site is located on an elevated platform approximately 8 m above Commercial Road, a publicly accessible thoroughfare with both vehicular and foot traffic. This design is unique in Australia, exposing public vehicles and pedestrians to the possibility of helicopter downwash on landing.
Figure 1: The Alfred hospital HLS
Source: OzRunways HLS database
The ATSB has received reports of 5 rotor wash events at various hospital helicopter landing sites since 2016. Of these, 3 occurred at The Alfred hospital helicopter landing site and all involved AW139 helicopters.
Safety action
The operator immediately ceased operations to The Alfred hospital helicopter landing site following the incident. Before re-commencing operations at the helipad, the operator:
reduced the maximum number of helicopters on the helipad from two to one, removing the requirement to hover taxi away from the centre of the helipad
implemented pedestrian marshalling procedures for all helicopter movements, so that operations will only occur when no pedestrians are within 30 m of the helipad.
Further, The Alfred hospital has engaged a helipad consultant to review the design of the helipad.
Safety message
Helicopters produce significant main rotor downwash, especially during hover taxi, take-off and while approaching to land. It is important that the risk of downwash related injuries, either by direct exposure or by being struck by loose items, be assessed prior to using a helicopter landing site (HLS).
As pilots have limited ability to reduce rotor downwash during these phases of flight, securing loose items in the vicinity of the HLS and keeping people a safe distance away are the most effective ways of preventing injury.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 26 May 2021, a BAE Systems Avro RJ100 (RJ100) aircraft was inbound to Port Augusta, South Australia, conducting a regular public transport service from Adelaide, South Australia, with 37 passengers and 4 crew on board. Also inbound to Port Augusta at about the same time, was an Ayres Corporation S2R-T34 (S2R) agricultural aircraft on a positioning flight from Broken Hill, New South Wales, with the pilot as the sole person on board.
The weather was reported as being generally good and suitable for a visual approach,[1] with a visibility in excess of 10 km, no cloud below 5,000 ft and a southerly wind at approximately 10 kt.
At 1337:06 Central Standard Time,[2] the RJ100 was 30 NM south of Port Augusta Airport at flight level 140,[3] and the crew made their first broadcast on the common traffic advisory frequency (CTAF), stating their intention to join the downwind leg of the runway 15 circuit with an estimated arrival time of 1345.
About 2 minutes later, while 14 NM north-east of the aerodrome and passing 2,500 ft on descent, the pilot of the S2R made their first broadcast on the CTAF advising of the aircraft’s position and estimated arrival time in the circuit area also of 1345 (Figure 1).
Figure 1: Inbound flight paths
Flight path of the Avro RJ100 and Ayres – positional data of Ayres S2R estimated.
Source: Google Earth and Flight Radar 24, annotated by the ATSB
The crew of the RJ100 reported hearing two radio transmissions simultaneously at this time, rendering both transmissions unreadable, but heard the end of the S2R pilot’s transmission stating ‘…Port Augusta’. In response to this, the RJ100 crew reported repeating their inbound radio call but did not receive a response. The pilot of the S2R did not recall hearing that broadcast from the RJ100 crew.
The crew of the RJ100 and the S2R both reported difficulty in being able to make or receive radio calls due to frequency congestion originating from an aircraft conducting circuit operations at Port Pirie aerodrome, which shared the CTAF.
Shortly after repeating their inbound call, and having not received a response, the crew of the RJ100 observed proximate traffic on the aircraft’s traffic alert and collision avoidance system (TCAS) 8 NM south-east of Port Augusta. The S2R was not equipped with a transponder, and as such was not visible to the crew of the RJ100 on their TCAS traffic display. However, the crew of the RJ100 stated that they believed that the TCAS traffic was the same aircraft that had made the previously unreadable radio transmission ending in ‘…Port Augusta’, and assessed that the aircraft did not pose a conflict to their arrival.
At 1343:18, the RJ100 was 5.9 NM south of the aerodrome at 1,500 ft above ground level (AGL) approaching the downwind leg of the circuit, and the crew broadcast on the CTAF that they were joining downwind for runway 15. At this time, the S2R was 9 NM north-east of the aerodrome. The pilot of the S2R reported hearing the transmission but believed the RJ100 was established on the downwind leg of the circuit, and therefore estimated it would be on the base or final leg of the circuit by the time the S2R reached the circuit area.
The pilot of the S2R planned to overfly the circuit at 1,500 ft AGL, descend on the non-active side of the circuit (Figure 2), and then join the circuit at 1,000 ft AGL for a landing on runway 15.
A short while later, as the S2R approached the circuit area, the pilot observed an RJ100 aircraft parked on the tarmac and concluded that it was the same aircraft that had previously reported joining the downwind leg and thought it must have landed. This was, however, another (company) aircraft that had operated into Port Augusta that day.
At 1345:03, the RJ100 was in a mid-downwind position for runway 15 at 1,500 ft. The S2R was approaching the circuit from the north-east also at approximately 1,500 ft. The captain of the RJ100 reported seeing the S2R from their window on the left side of the aircraft, as it passed from right to left about 50 ft directly below the aircraft (Figure 3).
Figure 3: Point of closest proximity
Flight path of the Avro RJ100 and Ayres S2R – positional data of Ayres S2R estimated.
Source: Google Earth and Flight Radar 24, annotated by the ATSB
The crew of the RJ100 expressed surprise on sighting the S2R, and broadcast on the CTAF ‘…did you see us?’ to verify if the other pilot had them in sight prior to the aircraft passing below. In response to this, the pilot of the S2R reported that they saw the aircraft pass behind them and had not been aware of the aircraft before then.
Operational factors
Non-towered aerodromes
The majority of aerodromes within Australia operate without the provision of air traffic control services. These aerodromes rely upon pilots broadcasting their positions and intentions on a CTAF and then implementing separation actions that are agreed directly between the pilots.
To guide pilots in interpreting the Civil Aviation Regulations relating to operations within a CTAF area, the Civil Aviation Safety Authority has promulgated guidance in Civil Aviation Advisory Publications (CAAP)
Figure 4: Recommended circuit height based on aircraft performance
CAAP 166-01 also states that:
where a pilot is unfamiliar with the aerodrome layout, or when its serviceability, wind direction, wind speed, or circuit direction cannot be ascertained prior to arrival, the overfly procedure should be used.
To mitigate the risk of a potential conflict between two aircraft of differing performance categories, and therefore circuit heights, where one aircraft is planning to overfly the aerodrome, the CAAP recommends that:
At aerodromes with high performance traffic in the circuit, the overfly height should be no lower than 2,000 ft above aerodrome elevation.
In this occurrence, the relative performance of each aircraft would mean that the RJ100 should fly a circuit at 1,500 ft AGL, and the S2R should fly a circuit at 1,000 ft AGL (Figure 5). In which case, the pilot of the S2R should conduct the overfly procedure at 2,000 ft AGL to remain safely above the RJ100’s circuit altitude.
Figure 5: Relative circuit heights of aircraft of different performance categories
The pilot of the S2R reported being unfamiliar with Port Augusta Airport, and as such elected to overfly the circuit prior to joining – in line with the requirements of CAAP 166-01. Unfortunately, the pilot of the S2R was unfamiliar with the operation of high-performance aircraft and the differing circuit heights stipulated in CAAP 166-01, and erroneously believed that the RJ100 would be conducting their circuit at 1,000 ft AGL. This resulted in the S2R conducting the overfly procedure at 1,500 ft, which was the same height at which the RJ100 was conducting its downwind leg.
Communications
Most non-towered aerodromes use a standard frequency for the CTAF. Some aerodromes that experience higher volumes of traffic, or are located close to other aerodromes, are assigned a discrete frequency. At the time of the occurrence, Port Augusta shared a frequency with the nearby aerodrome of Port Pirie. The crews of the RJ100 and S2R reported that the pilot of an aircraft operating at Port Pirie Aerodrome broadcast their position at each leg of the circuit being flown. This does not conform to the recommended broadcasts contained in
166-01 or align with its recommendation that the fundamental principle of operating in the vicinity of a non-controlled aerodrome is to only make the broadcasts necessary to ensure other aircraft are aware of your operation. The excessive and unnecessary transmissions contributed to the crew of the RJ100 being unaware of the S2R’s position and limited their opportunity to implement satisfactory separation.
Traffic alert and collision avoidance system
The TCAS enhances a pilot’s situation awareness by displaying traffic information regarding the position and altitude of other aircraft operating nearby. For aircraft equipped with a TCAS unit, the system will alert the pilot to aircraft in close proximity through a traffic advisory, and then issue an avoiding action to prevent a collision through a resolution advisory if required. The TCAS system gathers position and altitude data through an aircraft’s transponder output to display and generate traffic information to the pilot of a TCAS-equipped aircraft. In this occurrence, the RJ100 was fitted with an integrated TCAS unit, however the S2R was not fitted with a transponder. This resulted in the crew of the RJ100 not receiving any traffic information or resolution advisories regarding the S2R from the TCAS unit throughout the occurrence.
Safety action
In response to this occurrence, the operator of the RJ100 advised the ATSB that further advice had been disseminated to the company’s pilots regarding operations at non-towered aerodromes. Specifically, pilots had been requested to ensure that positional broadcasts are as accurate as possible and include the provision of ‘early, mid or late’ to best describe the aircraft’s position when broadcasting joining the downwind leg of the circuit. Pilots have also been encouraged to verify their intended circuit altitude in circumstances where any doubt exists as to the awareness of this among other aircraft.
The operator of the S2R advised the ATSB that they have reviewed the relevant CAAP regarding operations at non-towered aerodromes and ensured that all company pilots are familiar with the possibility of aircraft operating at differing circuit heights depending on their performance category.
Prior to this occurrence, safety concerns around frequency congestion and broadcast interference in the Port Augusta area had been reported to the ATSB through REPCON, the aviation confidential reporting scheme. This report and the ATSB’s comments are available as REPCON AR2020-0066.
Safety message
This incident highlights one hazard associated with operations at non-controlled aerodromes and reinforces the importance of pilots being thoroughly familiar with the recommended procedures and the likely traffic mix operating at the aerodrome. It is also a reminder to pilots to make clear and concise radio calls and eliminate unnecessary broadcasts, particularly within the CTAF environment.
Further, this incident serves as a reminder of the risk of confirmation bias during operational decision making. Confirmation bias is defined as the tendency to interpret new information as confirmation of existing hypotheses, and as such is a threat to situational awareness and sound decision making in the aviation environment.
In this occurrence, a company RJ100 on the ground at Port Augusta led the pilot of the S2R to erroneously conclude that the aircraft they heard joining the circuit had landed. While the conclusion drawn by the pilot was not unreasonable, it likely reduced the vigilance of the S2R pilot who reported then turning their attention to other tasks of navigation and communication.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
At about 2000 local time on 21 June 2021, the crew of a Gates Learjet Corporation Model 36 aircraft taxied to depart from Nowra, New South Wales. During the taxi, the crew had difficulty turning the aircraft.
After take-off, the crew received an unsafe landing gear indication when the wheels were retracted and in response, elected to extend the landing gear. When the landing gear was extended, the crew observed a normal cockpit indication and returned the aircraft to Nowra. A fly-by inspection revealed that the nose landing gear, while extended, was oriented side on to the direction of travel. Upon touchdown the nose wheel quickly straightened, and the landing roll proceeded without further incident.
After the flight, maintenance engineers inspected the aircraft. Their assessment was that during landing gear retraction, the uplock roller failed to engage the uplock latch because the roller was facing downwards after rotating through 180º during taxi. Prior to landing, the nose wheel was reportedly oriented side-on to the direction of travel. This is likely to have occurred when the crew extended the landing gear and the centring mechanism attempted to correct the orientation of the nose wheel.
Figure 1 shows the normal operation of the nose wheel landing gear when it is retracted. The uplock roller attached to the lower portion of the nose wheel landing gear leg is captured by the uplock latch in the wheel well. This closes a switch which provides the crew with a landing gear up and locked indication in the cockpit.
Prior to the flight, the aircraft’s nose wheel landing gear steering was marked on the maintenance release[1] with a Minimum Equipment List[2] (MEL) entry to notify the crew of a known fault with the system. The crew had signed the maintenance release and were aware of the defect. This fault affected the pilots’ ability to manipulate the nose wheel, however, steering was still possible through the use of differential braking. The flight manual specified that while operating with degraded steering performance, tight turns were to be avoided. The difficulty the crew experienced while positioning for take-off is likely due to the castoring lower portion of the nose wheel landing gear arm rotating through 180º to face in the opposite direction.
Figure 1: Normal operation of the nose wheel landing gear uplock
Source: ATSB
Safety action
As a result of this occurrence, the operator has advised the ATSB that they have taken the following safety actions:
The crew were alerted to the potential risks of the nose wheel being reversed due to sharp turns and the likelihood of experiencing turning difficulties.
Procedures were introduced to manage a possible reversed nose wheel during taxi.
Updated guidance was provided regarding the positioning of aircraft for dispatch when nose wheel steering was unserviceable.
Engineering held a meeting to highlight the importance of correct strut servicing and the identification of potential traps or error points.
Safety message
This incident highlights the importance of adhering to manufacturers’ recommended operating procedures, especially those imposed by Minimum Equipment List conditions. The Civil Aviation Safety Authority publication
Its purpose is not to encourage the operation of aircraft with inoperative equipment. Such operations are permitted only as a result of careful analysis of each item to ensure the required level of safety is maintained.
A thorough understanding of aircraft systems is required for a crew to accurately assess the effect a particular defect has on normal operations.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report and allow for greater industry awareness of potential safety issues and possible safety actions.
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
What happened
On 2 August 2021 at about 0900 local time, the student and instructor of a Cessna 172N aircraft, planned to conduct a one-hour local flight from Kalgoorlie-Boulder Airport, Western Australia.
The instructor and student held a pre-flight briefing, which included discussing fuel requirements for the flight including fuel reserves. The student calculated the fuel required based on a fuel burn rate of 38 L/hour and 30 minutes fixed reserve, in accordance with the company operations manual.
The student then dipped the aircraft’s fuel tanks using the approved dipstick to ascertain the fuel on board. The student determined there was 50 L of fuel in the tanks, although the recorded fuel remaining from the previous flight in the daily flight log was 55 L. The student assessed that this amount was sufficient for the flight and relayed the fuel required and fuel onboard to the instructor who replied that ‘sounded about right’.
Although the student believed there was enough fuel, they suggested a refuel to the instructor prior to departure, however, as another flight was planned after the occurrence flight, the instructor determined there would not be sufficient time to do so.
The flight was conducted for approximately one hour and the aircraft was landed without incident.
The aircraft’s usable fuel capacity was 195 L. After the flight, the aircraft was refuelled with 182 L, indicating the aircraft completed the flight with approximately 13 L of usable fuel remaining. This was 6 L short of the fixed reserve of 19 L.
Operator investigation findings
The aircraft operator conducted an internal investigation into the occurrence. Its findings included the following.
The minimum fuel required for the flight was approximately 65 L. This was made up of the 38 L flight fuel for 1 hour plus the 19 L fuel reserve and taxi fuel 5L (calculated on a consumption rate of 38 L/H)
As the student was nearing licence stage, the instructor felt some degree of confidence that the student had made the correct calculation. The student had conducted fuel calculations many times prior to the occurrence flight. Post-incident discussion revealed the student may have confused the reserve quantity required for the flight, however it could not be ascertained why the student made an error in calculation.
It was possible that perceived time pressure resulted in not refuelling prior to the flight. However, the student and instructor thought there was sufficient fuel on board.
The method of ascertaining the fuel on board is by way of approved clear plastic capillary tube. The tube, called a ‘fuel hawk’, is calibrated specifically to the individual aircraft. The student had been trained and was confident in the used of this device. The student stated that at lower fuel levels the device was harder to read. A survey of the company flight instructors revealed that some error was possible when dipping lower fuel levels. If the aircraft fuel state was found to be near the minimum fuel required, it was common practice to add fuel as a buffer.
Following the occurrence, it was found that the fuel dipstick had a calibration error. This error made any fuel reading below approximately 20 L harder to read and inaccurate.
Safety action
The aircraft operator advised the ATSB of the following safety actions.
Reinforcement of standard operating procedures
A safety alert will be sent out to remind all company instructors that confirming the amount of fuel required is onboard and is the responsibility of the pilot in command in accordance with the company operations manual. The issue will also be raised at the next instructor meeting.
Recalibration of aircraft dipsticks and fuel tanks
Following the occurrence, the aircraft’s fuel dipstick was recalibrated by the chief engineer. This recalibration and rectification of the error should improve the reliability of the dip sticks when reading lower fuel quantities. It will be recommended that the company’s other Cessna 172 aircraft dipsticks be recalibrated.
Safety message
This incident highlights the importance of correct fuel quantity management. It is the responsibility of the pilot in command to ensure adequate fuel is available for each flight. Also, operators are reminded of the importance of checking fuel quality and quantity before each flight and to use correctly calibrated fuel tank quantity measuring devices.
The Civil Aviation Safety Authority advisory publication,
, provides guidance for fuel quantity crosschecking, specifically that the crosscheck should use at least two different verification methods to determine the quantity of fuel on board the aircraft.
The incident also highlights the importance of clear communication between instructors and students.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
