What happened
On 6 June 2005, a Grob G115 D2, registration G-BVHF, was conducting a training flight at Dundee Airport as part of the Air Cadet Pilot Scheme. The flight was the second session in which a student was given full control of the aircraft for circuits and landings.
During the second circuit, the student performed a stable approach at a constant 65 kt. As the aircraft approached the runway threshold, the student began the process of aligning with the runway and reducing power for landing. During this phase, the aircraft experienced a sudden roll to the left. The instructor immediately took control, declaring "I have control," but noted that the student momentarily resisted the application of full power.
In an attempt to recover, the instructor raised the nose and initiated flap retraction to the takeoff setting. However, the aircraft failed to respond to these inputs, leaving a forced landing on the grass south of the runway as the only viable option. An air traffic control witness observed the aircraft appear to stall at approximately 50 ft, followed by the nose. The aircraft struck the ground with the left wingtip, subsequently impacting a fence with the left main landing gear. The nosewheel sheared off, and the aircraft slid into a fence post, causing extensive damage to the nose, propeller, and right wing. There were no injuries to the two crew members on board.
The investigation
The AAIB examined the aircraft and the flight circumstances. Post-accident inspections of G-BV05 revealed no mechanical deficiencies that would have preceded the event. The stall warning system, which utilizes a vane on the left wing, was found to be fully functional, and there was no evidence of any disruption to the flight control system.
Investigators also reviewed the actions of the crew. While the instructor believed the student resisted the application of power, the student maintained that the aircraft suffered from a lack of performance. Further flight testing by instructors at the flying school suggested that the left wing drop could be replicated if go-around power is applied without sufficient compensating right rudder, particularly if right aileron is applied without corresponding rudder input.