What happened
On 18 May 2004, a Grob G115E Tutor, registration G-BYWV, was conducting training flights at RAF Church Fenton, Yorkshire. The aircraft, operated by a provider for the Royal Air Force, was being flown by a student pilot on his third solo sortie. The mission involved practicing both powered and glide approaches to Runway 24.
During the flight, the pilot completed a series of circuits. After a successful powered touch-and-go and two glide approaches, the pilot initiated a third glide approach. During this final circuit, the pilot turned toward the runway earlier than usual, resulting in a shorter ground track. At approximately 200 feet above the ground, the pilot realized the aircraft was too low to reach the runway and attempted an aborted landing (go-around). However, upon advancing the throttle, the engine failed to provide the necessary power. The aircraft continued to descend at an accelerated rate, eventually stalling at roughly 75 feet. The aircraft struck the ground 260 metres short of the threshold, bounced, and slid for 50 metres. The impact caused the nose landing gear to collapse, resulting in a bent propeller and engine shock-loading. There were no injuries to the pilot.
The investigation
Investigators analyzed GPS data from the aircraft and compared it with precision approach radar. While typical glide descent rates for the Tutor are between 800 and 900 feet per minute, this specific approach showed a descent rate of approximately 1,200 feet per minute. This higher rate is characteristic of the aircraft when the propeller RPM is left at 'HIGH'.
The investigation established that the pilot likely inadvertently moved the mixture lever to the 'LEAN' position instead of moving the propeller lever to 'LOW'. This error effectively starved the engine of fuel, preventing power production during the go-around attempt, while still allowing the engine to windmill without obvious signs of shutdown. The investigation also noted that the pilot's late recognition of the poor approach and the subsequent handling of the aircraft during the go-around attempt contributed to the outcome.
Findings
- The pilot's limited flying experience.
- The pilot's aircraft handling during the attempted go-around.
- The inadvertent movement of the mixture lever to the 'LEAN' position instead of the propeller lever to 'LOW'.
- The lack of a physical gate or warning system to prevent or alert the pilot to the incorrect mixture setting.
- The practice of selecting 'LOW' RPM during glide approaches, which can lead to such errors.
- The late identification of a landing approach that was too low to be successful.
Safety action
Following the incident, the selection of 'LOW' propeller RPM has been removed from the unit's immediate emergency action checklists and is now only included as a note for use when glide range is critical. Additionally, recommendations were made to remind pilots to positively identify engine control levers and to consider installing warning devices for the mixture lever.