What happened
On 27 August 2007, a Bolkow 207, registration D-ENWA, departed from a private farm airstrip located approximately 2 nm east of Stapleford Aerodrome, Essex. The aircraft was performing a private pleasure flight, carrying the pilot, an adult passenger, and a young child.
During the takeoff roll, the pilot attempted to climb above nearby trees before the aircraft had reached the recommended climb speed. Witnesses observed the aircraft becoming airborne halfway along the 6SB m strip but noted a slow climb and lateral instability. The passenger reported that the aircraft appeared to stop climbing, prompting her to look ahead at the approaching trees. The aircraft then entered a right turn, followed by a sharp left wing drop and a rapid descent. The aircraft struck the ground 270 m beyond the end of the strip, impacting the left wing, landing gear, and propeller. A post-impact fire consumed the wreckage. The accident resulted in two fatalities (the pilot and the child) and one serious injury (the adult passenger).
The investigation
The AAIB examined the wreckage, the engine, and the propeller. The engine and propeller were found to be in good mechanical condition, with evidence that the engine was producing high power at the moment of impact. The aircraft was correctly configured for takeoff, with flaps set at 15 degrees and the trim set near neutral.
Investigators analyzed GPS data, which showed the aircraft's airspeed was well below the required climb speed. The investigation also reviewed the pilot's training history, noting he had recently completed a tailwheel conversion course but had not specifically requested instruction on short or soft-field takeoff techniques. Meteorological data confirmed light winds, which provided a minimal headwind component of approximately 5 kt.
Findings
- The pilot adopted an incorrect takeoff technique, attempting to climb at low airspeed to clear obstacles before accelerating to the safe climb speed.
- This technique increased induced drag and degraded the aircraft's climb performance, placing the aircraft closer to its stall speed.
- The downward slope of the strip and the presence of trees may have created an illusion that the obstacles were higher than they actually were, prompting the pilot to attempt an early climb.
- The lack of a significant headwind on the day of the accident meant the aircraft had less performance margin than in previous departures.