History of the Flight
The accident occurred on 6 November 2006 at approximately 1025 UTC during the second training flight of a student pilot working toward an AOPA Flying Companion’s Certificate. The instructor, seated in the left seat, briefed the student on the takeoff procedure, including the need to counteract the aircraft's tendency to veer left when power was applied. The student taxied the aircraft and lined up on Runway 24.
The Accident
After power was applied, the aircraft yawed left as expected. The student later reported being distracted and alarmed by the extent of the yaw, and focused on maintaining directional control with the rudder pedals. At approximately 60 kt, the instructor directed the student to apply back pressure on the control stick to initiate rotation. However, the student, consumed with rudder control, confused the throttle lever with the control stick and pulled back on the throttle, closing it. The instructor took control and, with the throttle closed and speed decaying, decided to abort the takeoff.
Attempted Stop
The instructor applied brakes but found no braking action on the wet grass. He released and reapplied the brakes without effect. He continued to pump the brakes, pulled the mixture to idle cut-off, and switched off the electrics. The aircraft crossed the motor circuit track at the end of the runway and struck a tyre barrier at an estimated 10 to 20 kt. Both occupants evacuated safely, and the airfield fire service arrived within a minute; there was no fire.
Eyewitness Account
The airfield flight information service officer (AFISO), also a private pilot, observed the takeoff run from the control tower. He noted an immediate left yaw that was arrested, followed by small turns side to side as the aircraft accelerated slowly. He then heard a marked reduction in engine power, followed by two slight increases that did not sound like takeoff power. When the aircraft passed the runway intersection, the power was cut, and the AFISO activated the crash alarm as the aircraft hit the tyre barrier. The instructor stated that he did not reapply power after the student reduced it.
Takeoff Performance
The aircraft's weight at takeoff was 1,326 kg, 219 kg below maximum takeoff weight. For the weather conditions, the manufacturer's performance figures predicted a takeoff ground roll of 229 m (including a 15% increment for dry grass) and a takeoff distance to 50 ft of 344 m, assuming a liftoff speed of 70 kt. The landing distance ground roll was 343 m on a dry paved runway and 478 m (40% more) on dry grass. The aircraft's flight manual did not provide figures for wet grass. The CAA recommends a factor of 35%+ for wet grass but warns that very short wet grass may increase landing distances by up to 60%.
Analysis
If the takeoff had proceeded normally, the aircraft should have reached 60 kt within 229 m, leaving 616 m of runway remaining. The stopping distance from 60 kt on dry grass would have been 478 m, less than the distance remaining. However, short wet grass can be significantly more slippery, making it impossible to definitively determine if the aircraft could have stopped had the takeoff run been normal.
Contributory Factors
The AAIB identified the following contributory factors: the delayed application of full power during the takeoff run, the student pilot's apprehension and inadvertent closing of the throttle, and the slippery wet grass.