Accident
On 25 September 2015 at 1416 UTC, a Robinson R22 Beta helicopter, registration G-DEFY, sustained substantial damage during a training flight at Elstree Aerodrome, Hertfordshire. The helicopter, powered by one Lycoming O-360-J2A piston engine, was being operated by a student pilot on his first solo flight. The pilot, aged 44, had 55 total flying hours, of which 53 were on type, with 10 hours in the last 90 days and 4 hours in the last 28 days.
History of the Flight
Following a satisfactory dual instruction session, the student pilot was briefed by his instructor to perform a solo takeoff, hover, and landing. The instructor vacated the helicopter and moved a safe distance away before signaling the student to proceed. The student completed pre-takeoff checks and began to lift gently into a hover from the grass surface. Before the helicopter stabilized, it rolled to the right and onto its side, suffering extensive damage. The pilot, who sustained a minor injury, exited through the cabin door and reported that the helicopter had been subject to dynamic rollover.
Investigation
The AAIB note explains that dynamic rollover may occur when one skid or wheel remains in contact with the ground and the helicopter rolls to one side. As it rolls, the horizontal component of the total rotor thrust produces a rolling moment about the point of ground contact, which is initially opposed by the aircraft's weight. If the roll angle reaches a critical value and the skid or wheel stays in contact, the helicopter will roll over.
Injuries and Damage
- Crew: 1 (minor injury)
- Passengers: None
- Nature of damage: Substantial