Loss of control

The pilot and his support crew arrived at the site in the late afternoon and decided to only carry out taxi trials. This was to allow the pilot to get the feel of the controls of his recently purchased, powered hang-glider before flight testing it the next morning. During the last taxi run, it appears that the aircraft became airborne inadvertently. The aircraft climbed steeply to a height of about 150 to 200 feet. Large pitch changes were noted before the attitude stabilised in near level flight. Almost immediately, a shallow right turn commenced which rapidly deteriorated into a descending spiral. The aircraft struck trees and the ground in a vertical dive. Total flight time was 15 to 20 seconds. The pilot had held a Private Pilot Licence some 18 years previously. An offer of flight training had been made by an experienced powered hang-glider pilot, but this offer has been refused because the pilot wanted to teach himself. The control logic of the powered hang-glider was exactly opposite to that of the conventional aircraft on which the pilot had experience.

At 1810 Eastern Standard Time on 30 August 2004, a Fairchild Industries Inc. SA226-T Merlin III aircraft, registered VH-SSL, departed Bankstown, NSW on a charter flight to Glen Innes, NSW with the pilot and seven passengers on board.

The pilot reported that he manually flew the aircraft in instrument meteorological conditions during the climb to flight level (FL)160. On levelling at the cruise level, he noticed that the aircraft was flying in a slightly right-wing low attitude. The pilot said that he applied left rudder trim to level the wings and engaged the autopilot. About 2 ½ minutes later, the autopilot suddenly disengaged without warning. The aircraft then rolled rapidly to the right and entered a steep spiral descent. A review of air traffic control radar data indicated that about 50 seconds later, the aircraft levelled at 5,200 ft. After the pilot regained control of the aircraft, he reported that he noticed that the right fuel tank gauge reading was 350 kg (437.5 L) greater than the left fuel tank gauge reading, and that the aircraft was ‘very heavy on the right-hand side’. The pilot then climbed the aircraft to FL130 and diverted to Tamworth, NSW without further incident. There were no reported injuries to any of the aircraft’s occupants.

The aircraft’s fuel system included a cross-flow valve that allowed pilots to balance the fuel between the aircraft’s fuel tanks if needed. The Merlin III Aircraft Flight Manual contained the aircraft operating checklists. The BEFORE STARTING ENGINES and DESCENT checklists required that the fuel system cross-flow valve switch be closed. The pilot reported that during the diversion to Tamworth he used the cross-flow valve to reduce the fuel imbalance. A subsequent engineering examination revealed no defects in the aircraft’s fuel tanks, fuel vent systems, the cross-flow system, and the cross-flow valve.

The pilot reported that he conducted the last flight in the aircraft a few days before the occurrence flight. The fuel remaining on board the aircraft after that flight was 500 L, and the right fuel tank contained about 150 L less than the left fuel tank. The pilot believed that he might have used the fuel cross-flow valve during that flight. When the aircraft was refuelled before the occurrence flight, 700 L of fuel was added to the right tank and 550 L to the left tank to give a total fuel load of 1,750 L. The pilot reported that after the refuelling ‘the gauges were pretty well reading the same’.

The pilot of a Cessna 340 departed Bankstown, NSW at 1223 ESuT, for Townsville, Qld via Walgett, St George, Roma, Emerald and Clermont. He reported that he climbed the aircraft to 16,000 ft and adopted a long range power setting of about 49% which equated to a true air speed (TAS) of 168 kts and a fuel burn of 141 lbs per hour.

As the pilot approached the ‘OLDER’ waypoint north of Clermont, he reviewed his fuel situation and, because of a strong tailwind decided to continue on to Cairns. He informed an enroute controller of his decision and requested, for fuel planning purposes, a clearance to allow him to track in the opposite direction on a one-way air route. The controller was unable to approve his request but offered the pilot a direct track to Biboohra, a navigation aid 20 NM west of Cairns. The pilot accepted the amended track with the intention of later requesting a more direct route to Cairns.

About 15 minutes later, the pilot requested a more direct track, but was told to call the approach controller for a possible clearance. He contacted the approach controller and told the controller that he had minimum fuel. The controller asked the pilot if he was declaring an emergency, to which he replied affirmative. The pilot later commented that he did this in the hope of expediting his arrival. He was instructed to descend to 6,500 ft and track direct to Cairns. The controller asked the pilot if he preferred to join the runway 15 circuit via a left downwind or right downwind, to which the pilot requested to join a left downwind. The pilot later commented that the aircraft fuel flow gauges were indicating a total flow of 140 lbs per hour and the fuel quantity gauges for the selected main tanks, although wandering somewhat, were ‘displaying a healthy amount’ considering that he was about 12 NM from his destination. As the pilot approached 6,500 ft, he requested a clearance for further descent, to which the controller instructed the pilot to descend to 4,000 ft.

As the aircraft descended to 4,000 ft, the pilot saw Cairns City, but could not see the runway at Cairns airport. The aircraft's distance measuring equipment (DME) indicated 9 NM to the DME navigation aid at Cairns Airport. The pilot reported that at about this time, he observed one of the fuel flow gauges indicating zero, while at the same time, one or both engines began to surge and run roughly. He immediately informed the controller of the situation. The controller asked the pilot if he was familiar with a local airstrip (Greenhill which is 10 NM to the southeast of Cairns airport), to which the pilot replied that he wasn't. The controller indicated to the pilot that the strip was situated in his two o'clock position at a range of about two miles and to be aware of power lines and the sugar cane. The pilot was unsure of what to look for and was unable to see the strip, but after conducting a number of steep turns, saw a cleared strip in a field. He decided that he had to land. He extended the landing gear, but realised that the aircraft was too high and attempted a 360-degree steep turn onto final to reposition the aircraft. However, the airspeed was rapidly decreasing and there was insufficient height to complete the approach. At 1729 EST, the aircraft impacted the ground short of the strip and slid for about 20 metres. The pilot was seriously injured and the passengers received minor injuries.

The ATSB did not conduct an onsite investigation. Witnesses reported that the aircraft's engines were operating just prior to the crash.

The aircraft’s fuel system included main, auxiliary and locker tanks on each wing. During normal operation each engine used fuel from either the main or auxiliary tanks on the corresponding wing. Access to the locker tank fuel was by pilot-activated transfer of the fuel from the locker tank to the same side main tank. Fuel not required by the engine was returned to the main tank regardless of which tank was selected. It was possible for fuel to vent overboard when the main tank was full and fuel was being drawn from the auxiliary tank and/or transferred from the locker tank. Each main tank contained an auxiliary fuel pump that provided fuel pressure for starting and in the event of an engine driven fuel pump failure. A transfer pump was also fitted to each main tank to continuously transfer fuel from the nose section of the tank to the centre sump area of the tank. A function of the pump was to permit steep descents with a low main tank fuel quantity. Pump operation could only be deactivated by pulling a circuit breaker.

The pilot later commented that he had checked the fuel tanks before departure and could confirm that they were full. The pilot had recently flown the aircraft from the USA to Australia.

The pilot later reported that the fuel flow indicator, that had indicated zero, had been repaired about nine months prior to the accident and although initially erratic had operated flawlessly for the last three months. He went on to say that he now has no recollection of what occurred after he descended below 4,000 ft and cannot recall the engines surging.

A number of flight plans, using reported winds from the Bureau of Meteorology, were prepared by the ATSB to consider a number of possible scenarios. These calculations included a greater fuel burn than planned by the pilot, departing with less than full tanks, incorrect fuel tank usage which could result in fuel being vented overboard or remaining in the auxiliary or locker tanks, or a different TAS and groundspeed because of power settings. The ATSB calculations indicated that the aircraft should have arrived, after a descent and straight-in approach from 16,000 ft, with about 95-100 minutes of fuel on board, if fuel management and flight planning were as reported.

At about 1030 Eastern Standard Time on 18 October 2010, a Cessna 172S aircraft, registered VH-VSK, was operating at low level near Durham Downs Homestead, Queensland. A pilot and one passenger were on board.

The pilot was assisting a ground party locate two horses. The aircraft was seen manoeuvring at low level before radio and visual contact was lost. A search later found that the aircraft had impacted terrain near a dry creek bed. Both occupants received fatal injuries, and the aircraft was seriously damaged.

The aircraft's impact attitude was consistent with a loss of control following aerodynamic stall. The pilot was reported to have told another pilot a few days before the occurrence that the aircraft's stall warning system was inoperative. However, the status of the stall warning system at the time of the occurrence could not be confirmed. The investigation identified some other issues which also could have influenced the safety of the flight.

The aircraft operator introduced a number of changes to its policies and procedures following the occurrence.

On 30 August 2010, the pilot of a Robinson Helicopter Company R44 Clipper II, registered VH-ZVF, was intending to operate a private flight from Jandakot aerodrome to Hillside station Western Australia (WA).

Shortly after lift-off, control was lost and the main rotor blades struck the concrete apron adjacent to the departure helipad. The helicopter rolled and came to rest on its right side. The helicopter sustained serious damage and fragments of main rotor blade entered the hangar. Other fragments of main rotor blade were scattered over a large area of the aerodrome. The pilot sustained minor injuries while the passenger was uninjured.

Subsequently, the pilot reported he might have failed to turn the hydraulics on prior to lift- off. This may have been due to distraction created by a problem with a communications system and the unfamiliar departure sequence. The following ATSB publication provides some useful information on distraction:

• Dangerous Distraction: Aviation Research Investigation Report B2004/0324

For a full copy of that report, please visit the ATSB's website at www.atsb.gov.au

On 16 December 1988, at approximately 1015 hours a Mitsubishi MU-2B60 Marquise aircraft crashed on a Pastoral property 55 km WNW of Leonora Airfield, Western Australia. The pilot and nine passengers were killed, and the aircraft was destroyed by the impact and a subsequent fire.

The report concludes that the aircraft probably accrued icing on the frame which caused the airspeed to decrease to the point where the aircraft stalled and entered a spin; and that the pilot did not become aware of the decreasing airspeed in time to take action to prevent loss of control.

and

On 26 January 1990 at 0105 hours, a Mitsubishi MU-28-60 Marquise aircraft crashed approximately 10 km NNE of Meekatharra, WA. The pilot and passenger were both killed, and the aircraft was destroyed by impact and a subsequent fire.

The report concludes that the aircraft probably accrued icing on the airframe which caused the airspeed to decrease to the point where the aircraft stalled and entered a spin; that the pilot was not previously aware of the ice formation; and that he did not take action to prevent the aircraft's speed from decreasing.

On 30 June 2010, a Cessna Aircraft Company 172H (C172), registered VH-RZV, with one pilot on board, was engaged in cattle spotting, about 21 km NNW of Cunnamulla, Queensland (Qld.).

While orbiting a water trough at about 500 ft, the pilot lost control of the aircraft. Damage to the aircraft was consistent with the right-wing colliding with a tree branch, followed by the aircraft impacting the ground inverted, with a steep nose-down attitude

The pilot sustained serious injuries, and the aircraft was severely damaged. The pilot reported that the most likely reason for the accident was an inadvertent stall. This probably occurred while the pilot was performing a steep turn, with his attention divided between flying the aircraft and looking for cattle.

Most stall/spin accidents occur when a pilot is momentarily distracted from the primary task of flying the aircraft. This accident highlights that even an experienced pilot performing a familiar task can be momentarily distracted, resulting in the loss of control of the aircraft.

On 12 May 2010, an instructor and student were conducting circuit training in an Eagle Aircraft Australia X-TS 150 aircraft, registered VH-FPP, at Jandakot Aerodrome, Western Australia. Soon after lift-off the engine started to run rough and lost power. The instructor took over control and, maintaining between 50 and 100 ft above ground level, turned the aircraft towards another runway. Near the end of that runway the aircraft pitched nose-up, stalled and collided with the ground, seriously damaging the aircraft and injuring the occupants.

There was no evidence found of an aircraft defect or anomaly likely to have significantly affected engine power. The investigation found that the decision by the instructor to turn downwind significantly increased the aircraft's energy and therefore the risk of aircraft damage and occupant injury in the case of a forced landing.

Preliminary report released 20 May 2010

On 28 March 2010, a Piper Aircraft Corp PA-30 Twin Comanche, registered VH-KDS, departed from Jandakot Aerodrome, Western Australia for a private flight under the visual flight rules. On board were two qualified pilots, both of whom were endorsed on the aircraft type. Following the failure of the aircraft to return to Jandakot later that day, a search was initiated to locate the aircraft and occupants. The following morning, the seriously-damaged aircraft was located and both occupants were found to have received fatal injuries.

Examination of onboard GPS information indicated that, while tracking towards Jandakot Aerodrome, the aircraft commenced a steep descent from about 3,500 ft above mean sea level that continued to ground level.

Preliminary report released 19 May 2010

On 22 March 2010, at 1009 Central Standard Time, an Embraer - Empresa Brasileira de Aeronautica EMB-120ER Brasilia with two crew, prepared to take off on a training flight from runway 29 at Darwin Aerodrome, Northern Territory. The crew were the only occupants. The training captain advised the aerodrome controller that the departure would incorporate asymmetric flight (simulated engine failure) and was approved by the controller to perform the manoeuvre.

After becoming airborne, witnesses reported seeing the aircraft roll and diverge left from its take-off path. They watched as the aircraft continued rolling left and entered a steep nose-down attitude. It disappeared into trees, south of the runway threshold from where a column of black smoke was seen shortly afterwards.

Aerodrome rescue and firefighting services were in attendance very shortly thereafter and extinguished the fire. Both pilots were fatally injured, and the aircraft was seriously damaged due to impact forces and an intense post-impact fire.