History of the Flight
An instructor and a student were conducting a basic helicopter training flight in a Robinson R22 Beta, registration G-OPAL. Before the flight, the instructor briefed the student on exercises including hovering, takeoff and landing, air taxiing, and transitions to and from the hover. The student had completed these exercises in previous flights and was progressing well.
During the flight, light drizzle began, causing small water droplets to accumulate on the outside of the windscreens, gradually reducing the pilots' vision. The instructor decided to fly a circuit of the airfield in an attempt to clear the droplets. While transitioning into the circuit, the instructor was monitoring the position of another R22 helicopter maneuvering ahead. The student turned to begin a transition from the hover to climbing flight. As the helicopter accelerated and achieved translational lift, it began to climb. The instructor, monitoring the other aircraft through the contaminated windscreen, resisted the student's attempts to raise the collective control lever to prevent entry into the 'avoid area' of the height-velocity envelope. Shortly after, the landing gear struck the ground and the helicopter crashed.
Analysis
During the transition, the moisture on the windscreen did not disperse. The instructor closely monitored the other R22 to ensure a suitable takeoff path. While doing so, he prevented the student from raising the collective, and may have actually lowered it, causing the helicopter to descend and the landing gear to contact the ground.
The 'avoid area' defines combinations of altitude and airspeed from which a helicopter would be unlikely to successfully complete an autorotative landing following an engine failure.
Survival Aspects
There was insufficient time for either pilot to transmit a distress call before impact. Immediately after the accident, the instructor shut down the engine and isolated the fuel. The student remained conscious but had difficulty speaking. They could not contact ATC as the radio was damaged and neither carried a mobile phone. After a few minutes, the instructor noticed fuel leaking from the left fuel tank. The student recovered somewhat, and the instructor confirmed neither pilot had sustained serious injury. The instructor assisted the student out of the helicopter, and they moved clear of the wreckage to await assistance.
ATC were not initially aware of the accident, likely because the control tower is soundproofed and the impact was not heard. The accident site was difficult to see from the tower. Routine radio calls were not required for helicopters in the training area, so ATC were not expecting any calls from the helicopter. The instructor estimated that about 10 minutes had elapsed since the accident. ATC were eventually informed and activated the crash alarm; the Airfield Fire and Rescue Service attended and applied foam to the wreckage.