Accident Details
On 10 October 2001 at 1420 UTC, a Robinson R22 Beta helicopter, registration G-ELFI, was on a training flight at Shobdon Aerodrome. The weather was fine with scattered clouds at 2,000 feet, temperature 15°C, and a southwesterly surface wind of 225°/15 gusting to 25 kt. The crew comprised an instructor holding an Airline Transport Pilot's Licence (42 years, 5,500 total hours, 4,300 on type) and a student pilot holding a Private Pilot's Licence (Helicopter).
Flight Profile
The instructor had successfully demonstrated a practice autorotation from 800 feet agl, turning through 180° during the descent. The student then positioned the helicopter for a second practice autorotation. The instructor briefed that he would take control in the final stages to demonstrate the correct flare height, and the student was to follow through on the controls during the demonstration. The normal profile for a 180° turning autorotation from 800 feet agl involves maintaining the turn until about 80 to 100 feet agl, rolling to a level attitude, then flaring at about 40 feet agl.
Incident Description
The student commenced the autorotation, which proceeded uneventfully until the instructor took over the controls with about 40 to 50° of the turn remaining. The instructor started the flare just as he rolled the helicopter to the level attitude at an indicated airspeed of about 65 kt and rotor rpm of 102%. Despite the application of aft cyclic pitch control, the helicopter maintained its downward trajectory. With insufficient time to use the engine to arrest the descent, the helicopter continued to the ground, impacting heavily in a level attitude but with considerable forward speed. During the subsequent deceleration, the helicopter rolled over and came to a halt on its right side. The instructor and student, both uninjured, exited through the broken front windscreen.
Post-accident Examination
The instructor stated that the student had followed through on the controls correctly and considered the most likely cause of the accident to be windshear at the point at which the flare was commenced. During a subsequent examination of the helicopter, no defects were found.