Loss of control

Updated: 23 July 2013

At about 1350 Central Daylight-saving Time[1] on 17 March 2013, an amateur built, 80 per cent scale replica of the Supermarine Spitfire Mk XXVI, registered VH‑VSF (VSF), took off from runway 21R at Parafield Airport, South Australia. The pilot was participating in an air display held in support of a local aircraft museum. Over the following 7 minutes the pilot completed a handling display orientated along runway 21/03 that was described by witnesses as relatively sedate, with a few steep turns with bank angles up to 60°, but no aerobatics. The weather was clear with a gusty south-easterly wind of up to 20 kt (37 km/h).

At the completion of his routine the pilot completed a final pass of the crowd on a close right downwind leg for runway 21 at about 350 ft above ground level. The aircraft, which had been operated in the clean configuration and at speeds around 120‑150 kt, was slowed to about 80 kt and configured with the landing gear down and a stage of landing flap as it passed the spectators (Figure 1).

Figure 1: Photograph taken of the Spitfire shortly before the accident as it flew past the spectator area on a downwind position for runway 21 at about 350 ft

Source: Airshow spectator, reproduced with permission

On the downwind leg the pilot communicated his intention to land to the air traffic control tower and enquired whether the wind still favoured a landing on runway 21. The aerodrome controller informed the pilot that the crosswind component was 11 kt (20 km/h) on runway 21 and runway 08 and cleared the pilot to manoeuvre as required to final runway 21L.[2]

A significant number of witnesses, some with piloting experience, observed the aircraft turn right base for runway 21L. They recalled that the aircraft appeared to be flying very slowly prior to an abrupt left turn away from the runway. Their accounts described a loss of control that was consistent with an aerodynamic stall followed by a significant wing drop. The aircraft was then observed to descend steeply toward the ground with a degree of spiral evident along the descent path before being lost to sight behind trees and buildings.

The aerodrome controller witnessed the aircraft descending out of sight and immediately instigated the aerodrome emergency response. A short time later the wreckage of the aircraft was located by emergency services in a factory car park about 1.5 km north of the runway 21L threshold. The pilot sustained fatal injuries and the aircraft was substantially damaged by impact forces (Figure 2). There was no fire.

Figure 2: Aircraft wreckage

Source: ATSB

Damage to the aircraft was consistent with it descending steeply into terrain at a high rate of descent in a wings-level, nose-down attitude. There was no evidence of in-flight structural failure. All of the aircraft’s components were accounted for at the accident site, with no evidence of pre-impact damage. Continuity of the aircraft’s flight and engine control systems was established and on-site evidence indicated that the engine was producing power at ground impact. The fuel tank ruptured on impact with the result that no fuel was available for testing. Examination of the airframe found that the aircraft did not incorporate any stall warning system.

A number of components were recovered from the accident site for technical examination including a global positioning system (GPS) receiver. The wreckage was documented and transported to a secure location for further examination as required.

Australian Transport Safety Bureau technical specialists examined the GPS receiver. That examination found that track data was retained in the receiver’s non-volatile memory. The GPS data for the accident flight was downloaded and is depicted at Figure 3.

Figure 3: Accident flight data recovered from GPS receiver[3]

Source: Google earth

A review of the recorded GPS data indicated that the aircraft descended to about 350 ft above ground level and the groundspeed reduced to about 80 kt on the downwind leg. As the aircraft turned onto the base leg for runway 21L, a gradual increase in height to 485 ft and reduction in groundspeed to 55 kt was evident. The position of the aircraft in relation to the runway at this point indicates that a tight turn would most likely have been required to line up on the runway centreline. It is possible that the pilot made a deliberate left turn away from the runway at this stage to allow more room to manoeuvre for final.

The GPS-recorded path of the aircraft was consistent with witness observations and, in combination with recorded wind data from the automatic weather station at Parafield Airport, indicates that the aircraft’s airspeed was close to the stall speed on base leg and most likely below stall speed as it abruptly turned left away from the runway. The GPS recorded time interval from the commencement of the base turn until the collision with terrain was about 20 seconds.

The reduced scale replica Spitfire Mk XXVI is a conventionally–configured, low-wing cantilever monoplane that is manufactured in kit form for construction by owner‑builders. The pilot constructed VSF in 2006 and had maintained it in accordance with the Civil Aviation Regulations since that time.

The pilot held a Commercial Pilot (Aeroplane) Licence and his pilot’s logbook indicated he had 1,665 hours flight experience, 190 of which were on the kit-built Spitfire. The pilot was the sole pilot of the aircraft, held a Class 2 Medical Certificate and was reported to have been rested and in good health prior to the flight. He was described as being meticulous with his approach to flying and maintaining the aircraft.

The investigation is continuing and will include:

• further examination of recovered components
• analysis of aircraft performance during the flight
• review of operational factors and the recorded data.

The final investigation report is planned for release to the public during October 2013.

The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

On 22 February 2013, VH-TGY (TGY) and VH‑TZJ (TZJ), departed a private airstrip near Bourke for Rumleigh, New South Wales. Both aircraft were to conduct aerial application (spraying) operations, which was supported by two ground personnel (mixers).

TGY landed at the Rumleigh and the mixers loaded the aircraft’s hopper. TGY departed and commenced spraying operations. Shortly after, TZJ landed at Rumleigh and was loaded. As the take‑off run on the south-eastern runway was commenced, TZJ’s fire-bombing door unexpectedly released and the 2,700 L load was jettisoned onto the ground, contaminating the runway.

About 15 minutes after, TGY landed on the north-west runway. When approaching the runway end, the pilot observed mud spraying up from the aircraft’s wheels. The aircraft then commenced sliding and turning to the left. When the left wheel contacted dry ground, the aircraft swung further left and tipped forward, resulting in the propeller contacting the ground. The aircraft then tipped backwards, and the tail wheel assembly detached. TGY sustained substantial damage.

The pilot of TZJ had attempted to contact the pilot of TGY on a number of occasions, but due to an unserviceable radio in TZJ, the broadcasts were not heard. The mixers elected not to contact TGY as they were of the understanding that he had been advised of the contamination by the pilot of TZJ.

A reliable communications system can assist with improving the overall efficiency and safety of an operation. This incident highlights the impact ineffective two-way communications can have on aircraft operations, and in that case, the need to consider alternative means for warning pilots of potential ground hazards.

Aviation Short Investigation Bulletin - Issue 19

What happened

On 15 February 2013, the crew of a Eurocopter Helicopter MBB‑BK117 B-2 (BK117), registered VH-VSA, were conducting a trauma recovery flight from Port Pirie to Adelaide Hospital, South Australia. After reaching the cruise altitude of 5,000 ft above mean sea level, the crew observed fluctuations of the hydraulic system pressure gauges. Shortly after, the helicopter sustained an uncommanded and violent nose-up pitch and rolled left before descending. The pilot regained control at about 800 ft above ground level. Control checks by the pilot confirmed normal control had resumed and the pilot flew the helicopter back to Port Pirie Aerodrome. No injuries were reported by the occupants and the helicopter sustained minor damage.

What the ATSB found

The ATSB did not find any mechanical or system faults that could account for the hydraulic system pressure fluctuations. The ATSB found that the helicopter was being operated at a weight, density altitude and airspeed, and in meteorological conditions that were conducive to the onset of retreating blade stall. The uncommanded and violent nose-up pitch and left roll were consistent with the onset of that condition. The pilot’s instinctive action of pushing the cyclic control forward delayed recovery from the stall.

What's been done as a result

The operator issued an urgent Immediate Safety Notification advising all company BK117 pilots of the conditions conducive to retreating blade stall and the correct actions to recover from that condition.

Safety message

This incident highlights the importance of pilot awareness of the factors conducive to retreating blade stall, including high all-up weight, high density altitude, high airspeed, manoeuvres that increase flight loads and flight in turbulence. Similarly, the importance of initially reducing collective pitch to optimise recovery is emphasised as incorrect recovery actions can result in loss of control of the helicopter.

On the evening of 28 January 2013, VH‑YFF was being prepared for a scheduled passenger service from Canberra, Australian Capital Territory to the Gold Coast, Queensland. The crew were aware of adverse weather conditions being experienced at the time in south-east Queensland and had been monitoring the weather at the Gold Coast throughout the day.

During the approach, the crew reported that they were in cloud and experiencing rain and a strong right crosswind of about 40-50 kt. The Tower controller advised the crew that the crosswind on the ground was 21 kt. The captain reported that he was mindful of the wind conditions and was prepared to initiate a go-around.

At about 1,000 ft above mean sea level (AMSL), the crew became visual with the runway.

At about 100 ft, the captain noted that the airspeed trend vector was indicating a 20 kt decrease, likely the result of undershoot windshear. The captain momentarily increased engine thrust.

At about 2229, the aircraft touched down about 200 m further along the runway than intended. The first officer (FO) recalled the aircraft touched down on, or slightly right of the runway centreline. At that time, they were experiencing light rain.

After touchdown, the captain perceived that the aircraft was close to the left side of the runway, due to the proximity of the runway edge lights. The captain immediately applied right rudder, however, he inadvertently overcorrected, resulting in the aircraft veering to the right side of the runway. The captain applied left rudder, and the runway centreline was regained. The aircraft was slowed to taxi speed and taxied to the terminal.

Due to the weather conditions and high workload at the time, the captain was not certain if the aircraft was pointing towards the runway edge before touchdown or if the aircraft aquaplaned after touchdown. The FO reported that it felt like the aircraft aquaplaned and drifted to the left.  However, after reviewing the flight data, the captain believed that the aircraft flared on centreline and drifted left before touchdown.

Through its SafetyWatch initiative, the ATSB is highlighting an increasing trend in problems with aircraft handling and flight profile when unexpected events arise during the approach to land. When compared to other phases of flight, the approach and landing has a substantially increased workload. Further details are available at www.atsb.gov.au/safetywatch/handling-approach-to-land.aspx

Aviation Short Investigation Bulletin  - Issue 23

On 19 January 2013, a Robinson R22 Beta II helicopter departed from a station homestead, located 10 km to the east of Manton Dam, Northern Territory. On board the helicopter were a pilot and a passenger.

On return to the homestead and on approach to land, the pilot reported that he had difficulty maintaining control of the helicopter in the hover and he elected to conduct a go-around. At about 40 ft above ground level, and at an airspeed of between 25 to 30 knots, the helicopter suddenly yawed to the right and completed 3 to 4 revolutions before impacting trees. The helicopter came to rest inverted and was seriously damaged. The pilot was able to exit with minor injuries and assisted the passenger, who was seriously injured, to exit the helicopter.

Wind will cause anti torque system thrust variations to occur in helicopters. Certain relative wind directions are more likely to cause tail rotor thrust variations than others. Knowing which direction the wind is coming from is critical – especially in light wind conditions. Any manoeuvre, which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur.

Aviation Short Investigation Bulletin - Issue 18

What happened

On 19 January 2013, a Bell 206B3 helicopter was being operated on an aerial filming task over hilly terrain on the north-eastern outskirts of Perth, Western Australia. The weather was fine with east to north-easterly winds of 10 to 15 kt.

After hovering and manoeuvring at about 500 ft above ground level to allow the camera operator to record footage of a truck accident, the pilot conducted a right orbit to complete filming and depart the area. The pilot had initiated the turn when the nose of the aircraft moved left, then suddenly and rapidly to the right as the helicopter yawed and developed a rotation of about five revolutions.

The pilot regained some control close to the ground, but assessed that the performance of the helicopter was insufficient to avoid a forced landing. In an area with a number of obstacles the pilot selected a clearing and managed the available energy to perform a low-impact landing. The slope was such that the helicopter immediately rolled over with the engine still operating, but importantly for occupant survivability did not catch fire. The pilot and camera operator sustained minor injuries while the helicopter was seriously damaged.

What the ATSB found

The ATSB found that when the pilot turned to the right to commence the orbit, the helicopter was exposed to a crosswind from the left while at an airspeed around the 30 kt threshold value for susceptibility to loss of tail rotor effectiveness (LTE), precipitating an unanticipated right yaw and temporary loss of control. The pilot regained sufficient control for a forced landing, but he did not use full left pedal as recommended for loss of tail rotor effectiveness, resulting in a likely delay in recovery.

What's been done as a result

The helicopter operator advised that as a result of the accident they conducted an internal investigation and implemented a number of safety actions in relation to LTE training and aerial work guidelines. In addition, the camera operators were issued with flight suits and helmets, and the operator advised the television station of the option to fit an externally-mounted gimbal camera that would allow the camera operator to remain seated and permit left or right orbits during filming operations.

Safety message

Aerial photography from most helicopters at relatively low airspeed and height, over hilly terrain in variable winds, is a challenging task with an inherent risk of LTE. In those circumstances, where visual cues can be misleading, pilot attention to airspeed, height and orientation to local wind is critically important. And, as demonstrated in this occurrence, LTE can be preceded by momentary strong yaw in the opposite direction, a characteristic which is counter-intuitive and has the potential to be confusing for the pilot.

As well as understanding how LTE can occur, pilots should be familiar with the recommended recovery techniques and apply them immediately to the fullest extent possible in the situation.

On 3 January 2013, the student pilot of a Robinson R44 (R44) Raven 1 helicopter, registered VH-RYO (RYO), was preparing for a training flight at Moorabbin, Victoria.

During the takeoff, the student slowly raised the collective and applied some left cyclic and left yaw control pedal, the helicopter became light on the skids, and started to slide and yaw to the left. The left skid then caught on the ground twice. The student became tense and inadvertently raised the collective instead of lowering it to reject the takeoff. He reported that his subsequent movements of the controls were erratic. The helicopter pitched upwards and the tail boom contacted the ground. The helicopter rolled and came to rest on its right side. The student received minor injuries and the helicopter sustained serious damage.

Aircraft fuels are a primary hazard in a post-accident aircraft fire. If ignited they pose danger to survivors, rescue personnel, fire services personnel, etc. This accident highlights the importance of considering all the potential hazards on an accident site before entering, and if there is any doubt, remain clear.

Aviation Short Investigation Bulletin – Issue 17

What happened

On 9 December 2012, the pilot of a Robinson R44 Raven I helicopter, registered VH-WOH, was conducting aerial spraying activities on a property near Mudgee, New South Wales. Following the completion of a number of spray runs, the helicopter failed to return to the refilling station, and a search was commenced. The helicopter was found about 450 m up a hill from the refilling station, having collided steeply with terrain. The pilot was fatally injured.

What the ATSB found

Analysis of the recovered global positioning system data identified that immediately before the accident the helicopter was climbing up a hill when the speed decreased below about 10 kt (19 km/h). The ATSB found that at the time of the accident the helicopter was over its maximum allowable weight, was too heavy to hover out-of-ground effect and as the speed decreased, the power required exceeded that available from the engine resulting in a probable reduction in main rotor RPM (overpitch) and a descent. The time between this point and the first contact with a tree was insufficient for the pilot to complete a recovery action. The ATSB also found that the spray system on the helicopter had not been installed by an approved aircraft maintenance engineer.

Safety message

This accident highlights the dangers of operating helicopters overweight, especially when performance is critical, such as when low flying or conducting aerial spraying operations. The use of manufacturer’s performance data will assist pilots in avoiding the circumstances associated with this accident.

Update 18 December 2012

At about 0825 Eastern Standard Time¹ on 9 November 2012, a student pilot and instructor departed Gold Coast/Coolangatta Airport, Queensland, for a training flight in VH-HBB, a SOCATA TB‑20 Trinidad. The student pilot had passed the general flying progress test (GFPT)², but the student had recently acquired the Trinidad aircraft and was under the supervision of an instructor to undergo conversion training for the new aircraft.

The student had primarily carried out their previous flight training on Cessna 172 aircraft (172) that had fixed landing gear and a fixed pitch propeller. The Trinidad differed from the 172 in a number of ways that included having retractable landing gear and a variable pitch, constant speed propeller. Those features were considered to be ‘special design features’ and the conversion training being undertaken included endorsements for those special design features. The flight on 9 November was the student pilot’s sixth and the instructor’s seventh flight in the aircraft, having accumulated 7.8 hours and 8.9 hours, respectively, during the previous flights.

On the day, the aircraft departed from Coolangatta to the north before turning south. The aircraft was initially being tracked by the air traffic control radar, but at about 60 km south-south-west of Coolangatta the aircraft flew outside radar coverage (Figure 1).

Figure 1: Flight path of VH-HBB

Source: Google Earth

The path taken by the aircraft following the loss of radar coverage was unknown. However, at about 0845, the pilot broadcast on the Lismore common traffic advisory frequency (CTAF) that they were about 8 NM (15 km) north of Lismore Airport, New South Wales (NSW) and inbound to conduct circuits³ on runway 33 at Lismore. Reports indicated that the aircraft had completed a number of circuits prior to the accident.

At about 0915⁴, a number of witnesses travelling along the Bruxner Highway between Lismore and Casino, NSW observed the aircraft make an abrupt steep left bank before pitching nose down and rapidly descending. The aircraft’s nose was then observed to have been raised and its rate of descent reduced before crossing the Bruxner Highway at very low height. The aircraft impacted the ground in a paddock adjacent to the highway. Both occupants on board the aircraft were fatally injured.

The Australian Transport Safety Bureau (ATSB) initiated an investigation and attended the accident site. The ground impact marks observed by the ATSB indicated that the aircraft impacted the ground in a left wing-low attitude with the nose of the aircraft level, or slightly nose-up. The left main and nose landing gear separated from the aircraft and it continued to skid along the ground. The aircraft continued through a wire fence, where the fuel escaped from the tanks and caught alight, before the right wing impacted the ground and the aircraft flipped over, coming to rest inverted about 170 m after the initial impact point (Figure 2). The engine separated from the fuselage during the impact sequence and came to rest about 13 m beyond the main aircraft wreckage.

Figure 2: Accident site

Source: NSW Police

An intense fuel-fed fire continued to burn around the aircraft following the accident. That fire destroyed a substantial amount of the aircraft structure (Figure 3).

The investigation is continuing and will include:

• examination of the engine and propeller
• examination of the experience of the student and instructor
• assessment of the aircraft’s handling qualities.

The evidence will be analysed and a final report completed detailing the findings of the investigation.

Figure 3: Main wreckage

Source: ATSB
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[1] Eastern Standard Time was Coordinated Universal Time + 10 hours.

[2] A GFPT indicates that a pilot has attained a standard in the safe control and handling of an aircraft. The test does not assess flight navigation beyond an ability to fly in the vicinity of the departure aerodrome and the approved training area. The pilot remains a student pilot until a private or a commercial flight test has been passed.

[3] A standard rectangular traffic pattern flown around an aerodrome when taking off from, or landing on a runway.    

[4] The local time at Lismore was 1015 Eastern Daylight-saving Time (UTC+11).

The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB’s understanding of the occurrence as outlined in the web update. As such, no analysis or findings are included in this update.

Update 12 November

ATSB investigators began the on-site phase of the investigation on Saturday 10 November.

The team has been liaising with the local police to secure perishable evidence, including the pattern of the wreckage and marks from impact.

The ATSB has retained the aircraft’s engine for later technical examination.

Over the next few days, the team will be:

• interviewing witnesses
• meeting with the aircraft operator
• retrieving aircraft and pilot records.

The on-site wreckage examination will be completed later today and the ATSB aims to finalise the investigation by November 2013.

This page will be updated as significant information comes to hand.

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9 November 2012

The ATSB is investigating an accident involving a SOCATA TB-20 that collided with terrain at Lismore on 9 November 2012.

The aircraft was seen to bank left and impact the ground. It was destroyed by fire and the two people on board died as a result of the accident.

The ATSB has sent a team of investigators to begin the on-site phase of the investigation. 

Investigators will be:

• examining the wreckage for evidence
• interviewing witnesses and aircraft operator
• reviewing maintenance documents.

The ATSB will also review the pilot’s training and experience and collate and analyse witness information.

If you have any information about the accident please call the ATSB on 1800 020 616.

What happened

On 11 July 2012, the pilot of a Piper Seneca I, registered VH-LCK, was conducting a freight-carrying flight between Broome and Port Hedland, Western Australia. The flight was conducted at night under the instrument flight rules. Witnesses who heard or saw the aircraft take-off reported hearing unusual noises from the engines during the climb. Other witnesses closer to the accident site reported hearing the engine sound suddenly cut out before the aircraft banked left and descended steeply towards the ground. The aircraft wreckage was located amongst sand dunes, about 880 m beyond the upwind runway threshold. The aircraft was destroyed, and the pilot sustained fatal injuries.

What the ATSB found

The take-off towards the ocean was conducted in dark night conditions with limited external visual cues. An on-board global positioning system (GPS) recorded a reducing ground speed as the aircraft approached and passed overhead the upwind runway threshold, but without a significant increase in climb performance. That reduction in ground speed occurred about the same time witnesses heard unusual noises from the aircraft’s engines.

In the absence of any identified environmental, airframe or structural factors, the witness reports and GPS data were consistent with the aircraft’s performance being affected by a reduction in engine power. Following the likely loss of engine power, the aircraft speed reduced significantly, resulting in uncontrolled flight, a steep descent and collision with terrain.

Although not identified as a factor contributing to this occurrence, post-accident examination of the aircraft’s fuel selector valves found the internal seals had deteriorated and allowed fuel to flow to the engines when the valves were in the OFF position. A review of the aircraft manufacturer’s maintenance instructions revealed this type of internal leakage may not be evident during routine maintenance, although a non-scheduled valve leak procedure was available.

What's been done as a result

The aircraft manufacturer has been advised that their maintenance instructions may not identify deteriorated fuel selector internal seals during routine maintenance. Airworthiness bulletin AWB 28-105, published by the Civil Aviation Safety Authority, recommended that owners and operators of Piper Seneca, and other aircraft fitted with similar fuel selector valves, regularly check their function.

Safety message

This accident highlights the need for pilots to closely monitor their aircraft’s airspeed and initial climb performance during take-off. The need for prompt identification of any performance degradation and optimisation of the aircraft’s available climb performance is emphasised. The accident also highlights the elevated risk associated with dark night conditions, which increase pilot workload, particularly in the case of abnormal aircraft operations.

The investigation also identified the potential for inadvertent operation of the engine magneto switches due to their close proximity to the landing and taxi lights and auxiliary fuel pumps, potentially increasing risk if these switches are operated at a critical stage of flight.