History of the flight
The accident occurred during the DeHavilland Moth Club rally weekend at Woburn Abbey, Bedfordshire. A private grass strip, designated Runway 01/19, approximately 550 metres long, was provided for the event. There were lakes off the end of Runway 19 and a public road across the end of Runway 01. The intended flight was to depart to a local airstrip for an overnight stop, in formation with a Tiger Moth. The Tiger Moth departed first on Runway 19 without problems, and G-AALY followed. During the takeoff roll, the aircraft bounced as it passed over a mound across the runway about halfway along its length. It then became airborne with a high angle of attack and, after a short distance, descended back onto the runway. As the runway appeared too uneven for the aircraft to accelerate, the pilot elected to steer to the right, hoping smoother ground would aid acceleration. Realising insufficient distance remained to abort the takeoff, the pilot aimed for an area possibly suitable for a safe landing beyond one of the lakes, maintaining full power in the hope that the aircraft would fly in ground effect over the lake. As the aircraft passed over the near edge of the lake, the pilot realised it could not climb enough to clear a four-feet-high bank on the far side. Approaching the middle of the lake, the aircraft stalled due to a high angle of attack; as it nosed over, the right lower wing touched the water, causing the aircraft to slew 180 degrees to the right. It came to rest in a nose-down attitude in about three feet of water. The pilot and passenger, who were uninjured, escaped and waded to the bank. The weather at the time was light and variable wind, good visibility, and temperatures between 23°C and 25°C.
Discussion
The pilot, in a very full, frank, and concise report, stated that the takeoff weight was 748 kg (maximum takeoff weight 839 kg) and that the centre of gravity was 13.13 inches aft of the datum, within limits of 10 to 16 inches aft of datum. He assessed that, following the first bounce, if he had pushed the stick forward he could have gained enough airspeed to fly, or if he had closed the throttle and abandoned the takeoff, he would have had enough distance to stop safely. Additionally, he indicated several factors that may have affected his judgement: being dehydrated due to constant pressures from the Moth rally event, hurried pre-departure preparation, 'go-mindedness' leading to a desire to continue the takeoff to fly in formation, warm temperatures reducing performance, a heavy load, and the aircraft being fitted with a cruise pitch propeller.
Summary
The bounce, which was both unexpected and outside the experience of the pilot, was significant in the sequence of events that led to the accident. The condition of the runway had caused some concern among pilots during the two-day event. The pilot, in his assessment, was not prepared for the bounce or the resulting short flight. He noticed that following the bounce the stick was further aft than normal and felt he may have been reluctant to put the stick forward for fear of bouncing again with such a relatively heavy aircraft. He was accustomed to short field operations due to his normal field being both short and narrow, and as the aircraft was fitted with a more powerful engine than the standard Gipsy Moth, his expectation had been for the aircraft to achieve more than adequate acceleration.