On 21 February 2014, a Bell 206B helicopter, registered VH-XJA, took off from Sunshine Coast Airport, Queensland, with an instructor and student pilot on board. The training flight involved conducting a series of simulated emergency procedures in the helicopter training area. A practice autorotation and two simulated engine failures in the hover were completed successfully.

At about 1000 EST, the instructor briefed the student on the next sequence to be flown: a practice autorotation using variations in airspeed to move the aiming point for the touchdown closer or further away, with a power recovery. When at about 1,000 ft above ground level (AGL), in the undershoot for runway 12, the instructor reduced the throttle to idle and directed the student to commence the practice autorotation.

The student lowered the collective and entered the autorotation. The instructor observed the airspeed reduce to about 60 kt, and then talked the student through reducing the airspeed to about 40 kt to move the aiming point for the touchdown closer.

When at about 20-30 ft AGL, the instructor directed the student to commence levelling the helicopter and the low rotor revolutions per minute (RRPM) warning horn sounded. The instructor realised that the throttle was still at idle and took control of the aircraft from the student. He controlled the yaw, levelled the helicopter, allowed the helicopter to sink, and completed the autorotation to the ground, however the helicopter landed heavily, resulting in substantial damage.

This incident highlights the complexity and dynamic nature of autorotation training sequences. Autorotation practice provides pilots with skills to be used in emergency situations, but carries inherent risks.


Aviation Short Investigations Bulletin - Issue 29