Accident Summary
On 17 January 2004 at 1135 UTC, a Robinson R22 Beta (registration G-UESY) was engaged in a training flight at Elstree Aerodrome, Hertfordshire. The aircraft was operated by a flight school with an instructor and a student pilot on board; no passengers were carried. The helicopter sustained moderate damage to the rotor blades and cockpit area. Both occupants, wearing lap and diagonal harnesses, vacated the aircraft through the broken windscreen without injury.
Sequence of Events
The student pilot had been assessed as competent in hovering, spot turns, hover taxiing, and ascending and descending, and had followed through on controls during earlier demonstrations. For the first practice landing, the instructor positioned the helicopter for a down-sun approach to avoid glare, resulting in a light quartering tailwind from the left. The landing was firm but controlled. During the student's first takeoff, the helicopter rocked forward due to incorrect rotor disc positioning. The instructor re-briefed the correct technique in the air, emphasizing the need for corrective cyclic input as the Robinson R22 tends to lift the right skid first. The following landing was again firm but controlled.
On the second takeoff, the student again allowed the helicopter to rock forward as it became light on its skids. The instructor applied a slight rearward cyclic correction to prevent forward tipping. During this correction, the helicopter rolled rapidly to the left. Before further corrective action could be taken, the rotor blades struck the ground, and the helicopter yawed to the right, impacting the ground on its left side.
Instructor's Assessment
Marks in the soft ground indicated that the rear of the left skid may have dug into the ground during the previous landing. Additionally, the uneven terrain placed the left skid lower than the right prior to the attempted liftoff. The instructor assessed that these factors, exacerbated by possible incorrect rotor disc attitude and the slight crosswind, led to a dynamic rollover event.