History of the Flight
On 16 October 2006 at 0930 hrs, a Robinson R44 II helicopter, registration G-CDJZ, was being prepared for a training flight at Denham Airfield. The student pilot, aged 44 with 240 hours of flying experience (7 hours on type), was alone in the helicopter. The instructor intended to board after the engine was started with rotors running. The student started the engine without difficulty and continued with the 'starting engine and run-up' checklist. The final item required setting rotor rpm to 101-102%, then lifting the collective lever and reducing rpm to check the low rotor rpm warning light and horn at 97%. As the student lifted the collective lever, the helicopter began to move. The student's response resulted in violent control inputs, causing the tail boom to be severed by the main rotor. The helicopter remained upright, and the instructor joined the student to shut down the helicopter. The student was uninjured.
Discussion
Although the student had experienced a number of starts, this was the first occasion he had carried out the entire process alone. It is normal practice for students to build confidence in starting a helicopter on their own prior to flying solo. However, in this case, the student continued with the checks beyond the point briefed by the instructor. The student also held a fixed wing Private Pilot's Licence.
Similar Previous Incident
A similar incident occurred to a Robinson R22 Beta, G-DELT, on 16 October 2003. During the pre-flight low engine rpm warning horn check, the aircraft suddenly yawed to the left and became airborne. The student pilot, who was alone at the controls, was unable to regain control before the aircraft rolled over.
Regulatory Action
As a result of the 2003 accident, the CAA introduced an amendment to the Air Navigation Order, effective 15 March 2007. The amendment added after article 50(4): "An operator shall not permit a helicopter rotor to be turned under power for the purpose of making a flight unless there is a person at the controls entitled in accordance with article 26 of this Order to act as pilot-in-command of the helicopter."