What happened
On 20 September 2009, a Nord NC854S, registration G-BGEW, departed from the private grass airfield at Bourne Park near Andover for a flight to Swindon and Popham. Shortly after takeoff, witnesses observed the aircraft climbing over rising ground in a nose-high attitude. At a height of approximately 250 to 300 feet, the aircraft was seen to drop a wing, recover, and then drop the opposite wing before entering a steep, nose-down descent. The aircraft struck the ground at Whistlers Farm, approximately 4 miles north of Andover, in a state consistent with an incipient spin. A significant post-impact fire destroyed the aircraft, and both the pilot and the passenger sustained fatal injuries.
The investigation
The AAIB examined the wreckage and the engine components. While the fire destroyed much of the forward fuselage, investigators found that the primary flight control cables remained intact. The engine was found to be operating at high power at the moment of impact, evidenced by the fracture of the propeller hub. Examination of the exhaust system revealed significant deterioration, including de-lamination of the four gaskets and deformation of three engine cylinder flanges. This condition suggested that exhaust gases may have been escaping into the engine bay.
Additionally, toxicology reports indicated elevated levels of carbon monoxide in both occupants, with the pilot reaching 24.7% COHb. While the source was not definitively proven, the poor condition of the exhaust gaskets provided a likely mechanism for gas entering the cockpit. The investigation also reviewed the aircraft's weight and balance, noting that the aircraft was carrying a substantial fuel load.
Findings
- The aircraft entered a stall and spin due to a loss of control at a low altitude.
- The pilot's decision to continue climbing over rising ground, rather than maneuvering for a precautionary landing toward lower terrain, left no margin for error.
- Exhaust gas leaks likely introduced carbon monoxide into the cabin, which may have impaired the pilot's judgment or physical capability.
- The aircraft's climb performance was likely compromised by the high nose-up attitude and potential engine power loss from the leaking exhaust system.