What happened
On 13 August 2007, a Tipsy Nipper T.66 Series 3 Nipper, registration G-ONCS, was performing a practice aerobatic sequence near West Mersea and Tollesbury, Essex. The pilot intentionally initiated a right-hand spin by reducing throttle to approximately 30 kt. However, instead of the expected nose-down attitude, the aircraft entered a flat spin.
During the prolonged rotation, which lasted approximately 26 turns and 40 seconds, the pilot attempted several recovery techniques, including standard inputs and bursts of engine power, with little success. The aircraft's engine eventually stopped. After the spin finally transitioned into a more recoverable nose-down mode, the pilot attempted an emergency landing on marshy ground. During the landing approach, the aircraft struck a wire fence, causing it to flip and come to rest inverted. The pilot escaped the aircraft without injury.
The investigation
Investigators examined the aircraft's configuration and the pilot's flight data. The aircraft was equipped with a webcam and laptop used for flight review. Analysis of the video footage confirmed the aircraft's pitch attitude flattened significantly during the spin. The investigation also noted that the aircraft's center of gravity was near the aft limit, which is a known factor in influencing spinning characteristics.
Findings
- The aircraft entered a flat spin mode that was much more difficult to recover from than the pilot's previous experiences.
- The combination of an aft center of gravity and the pilot's specific entry technique—using left aileron to encourage the spin—contributed to the unusual rotation.
- The pilot experienced post-spin disorientation, which hindered the ability to focus on instruments during the recovery.
- The aircraft's tail configuration may have been less effective during the flat spin due to the blanking effect of turbulent air from the stalled tailplane.