What happened
On 25 June 2020, a Savannah VG, registration G-CGTV, was performing a private evening flight from a farm strip near Driffield, Yorkshire. The pilot intended to fly to Beverley Airfield. The takeoff was conducted from a 220-metre dry grass strip with the flaps set to the standard 20° configuration.
During the takeoff roll, the aircraft's main wheel struck a bump. This impact caused the pilot's knee to inadvertently strike the flap lever, shifting the setting from 20° to the 40° position. Because the aircraft was moving at low speeds, the flaps extended under their own weight. This sudden change significantly increased drag and altered the aircraft's lift characteristics.
As the aircraft climbed, the pilot experienced a sensation of the left wing stalling. In an attempt to maintain altitude and avoid power lines at the end of the strip, the pilot lowered the nose and applied left rudder. This maneuver caused the aircraft to veer left, eventually striking a stack of hay bales approximately 10 metres above the ground. The aircraft then impacted the ground tail-first, resulting in the destruction of the aircraft. The pilot sustained minor injuries.
The investigation
The AAIB examined the flap mechanism and found no mechanical defects. The investigation noted that the Savannah VG features a flap lever located on the cockpit floor between the pilot's legs, which is susceptible to accidental movement.
Investigators reviewed the Pilot's Operating Handbook (POH), which warns that a takeoff using 40° flaps is a delicate maneuver because the stall speed and lift-off speed are very close. The investigation also considered the takeoff distance; while the POH specifies a 228m distance to clear a 50ft obstacle, the available runway length was only approximately 220m, and the effective distance decreased as the aircraft veered left.