The loss of control and collision with terrain of a Bristell S-LSA aircraft clearly demonstrates the catastrophic consequences of conducting aerobatic flight in a non-aerobatic aircraft, without adequate training in the specialist techniques and methods required for maintaining aircraft control, a new ATSB report says.
On 5 October 2018, the pilot of the Bristell aircraft departed Moorabbin Airport, Victoria with the pilot and passenger on board for a navigation exercise in support of the pilot’s commercial pilot training requirements. After take-off, the flight headed over the northern part of Port Phillip Bay. Automatic Dependence Surveillance Broadcast data and on-board flight and GPS data showed the pilot commenced significant manoeuvres including steep climbs, descents and turns in excess of 90 ° angle of bank between 600‑1,300 ft above ground level (AGL) over a built up area west of Melbourne.
The aircraft then headed north west until overhead Stawell Airport. Once past the airport, a number of witnesses saw the aircraft commence a 180° turn to the south-east followed by a series of steep climbs and turns and then abruptly enter an upright spin and descend out of view. The aircraft maintained the spinning descent until it impacted terrain. The pilot and passenger sustained serious injuries and the aircraft destroyed.
The ATSB investigation found that contrary to the aircraft’s limitations and the pilot’s qualifications, aerobatic manoeuvres were conducted during the flight, and immediately before the loss of control. The aircraft then experienced an accelerated aerodynamic stall and entered into an upright, fully‑developed spin. Although the pilot did not consistently apply the manufacturer’s recommended spin recovery technique, recovery from a fully‑developed spin may not have been possible in aircraft types not approved for spinning.
The ATSB safety message from the investigation emphasises that aerobatic flight should not be undertaken by pilots who are not been adequately trained, as it requires specialist techniques and methods to maintain control of the aircraft during significant manoeuvring.
In addition, pilots need to be aware that when the aircraft manufacturers stipulate flight limitations and prohibit aerobatics in their aircraft types, this means the aircraft has not been designed or tested to ensure these manoeuvres can be done safely. Related warnings, advice and instructions need to be followed.
The aircraft’s data recording system was integral in determining the magnitude of the aerobatic manoeuvres during the accident flight. They can also be a readily accessible tool for both flying training and maintenance.
The ATSB identified that the operator had not installed an optional SD back up memory card for the aircraft’s Garmin G3X integrated instrument and avionics system. Therefore, had the avionics unit been damaged valuable data could have been lost.
Aircraft owners are encouraged to make themselves aware of the data recording capability of their aircraft and ensure that the systems are fully functioning and backing up information.
You can find here the investigation report
