What happened
On 27 April 2001, a Montgomerie-Bensen B8MR, registration G-BTBL, was prepared for a private pleasure flight from the grass runway at Roddidge Flying Club, located near Alvewas. The aircraft had been stored in a partially enclosed hangar throughout the winter months. Prior to the flight, the pilot conducted an inspection and ran the Rotax 532 piston engine for several minutes while the fuel tank was three-quarters full.
During the takeoff roll, the aircraft achieved lift and became airborne approximately halfway down the runway. However, once the aircraft reached an altitude of roughly 10 feet, it suffered a sudden loss of engine power. While the pilot managed to maintain a straight flight path, the helicopter's altitude steadily decreased. The pilot attempted an emergency landing in an adjacent field of sugar beet, but the aircraft struck a one-metre-high bank of soft soil at the edge of the field. This impact caused the helicopter to roll over, resulting in damage to the landing gear, propeller, rotor blades, and mast. The pilot sustained no injuries.
The investigation
The investigation focused on the circumstances surrounding the engine failure and the environmental conditions. Investigators noted that while the aircraft had been stored in a hangar, the structure was not fully enclosed, potentially exposing the engine and fuel system to the elements. At the time of the accident, the weather was fine with a 5 mph headwind and 20 km visibility. The pilot noted that there had been showers earlier in the day, though conditions had dried by the time of the flight.
Findings
- The engine failure occurred immediately after the aircraft reached a low altitude of 10 feet.
- There was no clear indication of the specific mechanical cause for the power loss.
- The pilot ruled out carburetor icing due to the high power setting and dry weather conditions.
- The presence of water contamination within the fuel was considered a possible contributing factor.