What happened
On 5 September 2006, a Murphy Rebel, registration G-BZFT, was performing a private flight near Branscombe, approximately 10 nautical miles east of Exeter. Following a successful three-point landing on Runway 27, the aircraft completed roughly half of its anticipated ground roll before beginning an uncontrolled left turn. Despite the pilot applying full right rudder and full right braking, the aircraft could not be corrected and entered a ground loop. During this maneuver, the right landing gear leg collapsed, and the aircraft continued to rotate through approximately 120 degrees before coming to rest on its right wingtip. There were no injuries to the two occupants on board.
At the time of the incident, the pilot reported calm surface conditions, though local thermal activity was noted. The aircraft's centre of gravity was confirmed to be within safe operating limits.
The investigation
The investigation examined the aircraft's history and mechanical condition. It was noted that the aircraft had experienced two previous ground loops. The first was attributed to a landing technique error by a different pilot, while the second occurred during a landing roll and was potentially influenced by crosswinds.
During the inspection of G-BZFT, investigators identified two potential mechanical contributors. First, a main wheel bearing was found to be stiff, even when the retaining nut was tightened to the manufacturer's specified torque. Second, investigators noted existing damage to the fuselage skin near the tail-wheel mounting point, which may have contributed to instability during the ground loop.
Findings
- The aircraft's centre of gravity was within the permitted range.
- The pilot possessed significant experience with tail-wheeled aircraft.
- A stiff main wheel bearing was identified as the most likely cause of the sudden yaw.
- Damage to the rear fuselage near the steerable tail-wheel unit may have contributed to the occurrence.