Aircraft and Flight Details
A Grob G115E Tutor, registration G-BYWV, was involved in an incident on 18 May 2004 at RAF Church Fenton, Yorkshire. The aircraft was operated by a civilian company providing aircraft and support for Royal Air Force elementary flying training. The pilot was a 20-year-old overseas Air Force student with 13 hours of flying experience, all on type. This was his third solo sortie, and he was briefed to practice normal powered and glide approaches to Runway 24. Weather conditions were fine with a surface wind of 260°/13 kt.
History of the Flight
After a dual check with a Qualified Flying Instructor, the student was cleared for solo circuits. He completed a powered approach touch-and-go, followed by three glide approaches. On the first two glide circuits, he executed a touch-and-go and a go-around, respectively. On the third glide circuit, he initiated the final turn slightly earlier and closer to the runway. At about 200 feet above ground level, he realized he was too low to glide to the runway and attempted a go-around. When he advanced the throttle, the engine did not respond, and the aircraft continued descending at a reduced rate before appearing to stall at about 75 feet agl. The aircraft bounced and slid for about 50 meters before coming to rest. The Airfield Fire and Rescue Service arrived about two minutes later, and the pilot vacated the cockpit unaided. No injuries were reported.
Damage
The nose landing gear collapsed, the propeller was bent, and the engine was shock-loaded.
Analysis
Stored GPS data and precision approach radar data were analyzed. On the first two glide circuits, the rate of descent around the finals turn was about 800-900 feet per minute. On the third circuit, the rate of descent was about 1,200 feet per minute, which is typical of the Tutor's glide performance when the propeller RPM lever is left at HIGH. The unit inquiry suggested that the higher rate of descent and the engine's failure to respond were probably due to the student inadvertently moving the mixture lever to LEAN instead of the propeller lever to LOW. This would have starved the engine of fuel while allowing it to windmill without obvious symptoms. When the student attempted to go around, the engine did not respond, and the aircraft landed heavily.
Causal Factors
The unit inquiry suggested the following causal factors may have influenced the accident:
- The pilot's lack of flying experience.
- The pilot's handling of the aircraft during the attempted go-around.
- The lack of a gate or warning device to prevent inadvertent movement of the mixture lever to LEAN or to warn of such movement.
- The practice of moving the RPM lever to LOW to simulate best gliding performance following an engine failure.
- The late recognition of a poor approach by the pilot.
Safety Recommendations
The unit inquiry made the following safety recommendations: 1. Remind Tutor pilots of the importance of positively identifying engine control levers before moving them. 2. Consider fitting a gate or short-term audio warning device to prevent or warn of inadvertent selection of Mixture to LEAN. 3. Consider practicing glide approaches with the RPM selected to HIGH.
Safety Action
The selection of propeller RPM to LOW was removed from the unit's emergency immediate and subsequent actions and is now only a note in emergency handling drills. RPM LOW is to be selected only if glide range is critical.