What happened
On 8 May 2005, a Eurocopter SA3lar2J Gazelle, registration F-GJSL, was performing a private flight near Dymock, Gloucestershire. While approaching a private landing site at Ockington Farm Strip, the pilot attempted a left-hand spot turn to position the aircraft for an into-wind landing.
During the maneuver, the aircraft experienced a rapid increase in the rate of yaw to the left. Believing the aircraft had lost directional control due to a wind gust, the pilot applied increased collective pitch and aft cyclic. This action, combined with the pilot momentarily releasing the collective to reach for his passenger, caused the aircraft to descend and yaw further. The helicopter struck the roof of an adjacent building, causing the tail boom to detach and the main fuselage to fall to the ground. Both the pilot and the passenger sustained serious injuries.
The investigation
Investigators examined the wreckage and found that the impact with the roof had severed the rear structure, including the tail boom and fin. The impact also caused the tail rotor drive shaft to fail. Examination of the flight controls showed no evidence of pre-impact mechanical failure.
The investigation also looked into the pilot's experience, noting that while he was an experienced helicopter pilot, he had only 12 hours of flight time on this specific type. Furthermore, the investigation reviewed the aircraft's seat configuration, noting that the front seats were only equipped with lap belts, as per the French registration requirements at the time of manufacture.
Findings
- The pilot's attempt to increase collective pitch to counter a perceived loss of control actually increased the torque-induced leftward rotation.
- The pilot's momentary release of the collective lever contributed to the uncontrolled descent.
- The lack of upper torso restraints on the front seats contributed to the severity of the passenger's injuries.
- The aircraft's specific handling characteristics, including the weathercock effect of the large tail fin, made the spot turn challenging in the prevailing wind conditions.