Introduction
An instructor and a student were conducting advanced emergency training in a Robinson Helicopter Company R22 (R22) helicopter, registered VH-8BW, at Pannikin Island in Moreton Bay, Queensland. Near completion of a commercial helicopter pilot lesson, the instructor and student agreed to conduct torque turns, an advanced helicopter handling manoeuvre that was outside of the training syllabus. After conducting several torque turns, the helicopter entered an increased low nose attitude during recovery at low altitude, which resulted in a collision with terrain and dynamic rollover.
Decision-making
The decision to conduct torque turns was only discussed between the instructor and the student during the flight. The instructor assessed the student to be capable of performing the manoeuvres based on their recent progress and performance during the lesson and having completed many previous training hours together. However, this assessment was done during the training flight, limiting the time available for the instructor to fully consider the benefits and risks, including the height to conduct the training. The torque turns were not part of the syllabus and were not necessary for the lesson. The benefits of conducting a pre-flight brief of the lesson, especially where training operations are conducted in emergencies, is well-established. Such a briefing reaffirms standard operating procedures, promotes predictable behaviour, and sets expectations. If the decision to conduct torque turns had been agreed before flight, that would have allowed for a full ground briefing to establish the torque turn procedures.
Manoeuvre Height
Torque turns were outside of the advanced emergency lesson for the operator’s commercial pilot training syllabus, and consequently no procedure was identified in the training materials for conducting them during training. The absence of a defined procedure places the reliance on the instructor to become the risk control. In this case, there was an increase in risk as the manoeuvre was conducted at a height that reduced the available safety margin and limited the opportunity for recovery when the helicopter entered an undesired state. If the manoeuvre had been initiated at a higher altitude, the increased height would have provided more time for the student and instructor to identify, intervene, and recover from the undesired aircraft state. Beginning the low-level torque turn exercise at 50 ft AGL, rather than starting higher and working down as the student’s capability improved, increased operational risk.
Instructor Recovery
During the torque turn, the helicopter exited the manoeuvre in a lower than expected nose attitude. Instructor intervention is a critical control in flight training and is often the final opportunity to regain control of the helicopter. Although the instructor took over control as soon as they recognised the rapid descent rate, the low height on exiting the torque turn limited the time available to arrest the descent before ground contact occurred. Environmental conditions may have further reduced the safety margin and complicated the low-level recovery. Due to the high speed of the helicopter and approaching vegetation, the instructor likely attempted to slow the helicopter using rear cyclic, however, after skid contact with the ground in an upright attitude, this likely resulted in the main rotor disk flexing and making contact with the tail boom. This resulted in the severing of the tail boom by the main rotor blades, loss of torque control, and the front left skid digging into soft soil, leading to a dynamic rollover.
SARTIME
The operator had no formal process for monitoring the return of training flights. Many operations were conducted within line-of-sight or in close proximity to the operator.