What happened
On 1 December 2005, a Robinson R44 Raven, registration G-ODHG, was involved in an accident at Sywell Airfield, Northants, during a private flight. The pilot intended to perform a hover taxi to the eastern side of the airfield to collect an instructor before departing for Cannock.
After completing pre-flight inspections and starting the engine, the pilot raised the collective lever to lift into a hover. During this initial attempt, the helicopter experienced a significant yaw to the left and the nose pitched upward. To avoid drifting into nearby parked aircraft, the pilot lowered the collective and applied right tail rotor pedal to correct the yaw. This maneuver resulted in the helicopter facing a different parked R44.
In a second attempt to lift into the hover, the pilot moved the cyclic control aft to prevent movement toward the parked aircraft. This second attempt resulted in a left yaw and a high nose-up pitch. Despite efforts to correct the attitude, the helicopter pivoted around the rear of the left skid, causing the main rotor blades to strike the ground. The aircraft rolled onto its right side, resulting in the aircraft being destroyed. The pilot escaped the wreckage uninjured.
The investigation
Investigators examined the weight and balance of the aircraft, noting that the helicopter was fully fueled in both the main and auxiliary tanks. The calculated center of gravity (CG) was 101.25 inches from the datum, which was near the aft limit of the allowable range.
Analysis of the pilot's experience revealed that while the pilot had significant experience in the R22, they had only 11.6 hours of experience on the R44, with only 3.2 hours as pilot-in-command. Furthermore, this was the pilot's first time flying the R44 solo with a full fuel load.
Findings
- The pilot may have applied excessive left tail rotor pedal during the first lift attempt, causing the initial yaw.
- The combination of an aft center of gravity, left pedal input, and increased aft cyclic during the second lift attempt caused the helicopter to yaw left and adopt an extreme nose-up attitude.
- The pilot had not previously experienced such severe flight attitudes and was unable to prevent the rotor blades from hitting the ground.