While performing an aerobatic wing walking display over the sea at Bournemouth Air Festival, the aircraft experienced a reduction in engine power. The pilot stopped the routine and flew the aircraft west, while the wing walker returned to her seat in the front cockpit. The engine subsequently experienced a complete loss of power and the pilot ditched in the entrance of Poole Harbour. The aircraft flipped over on contact with the water, but both the pilot and the wing walker were able to exit the aircraft unaided.
The investigation found that the loss of engine power was due to a failure of the oil inlet pipe most likely due to fatigue, which prevented oil being supplied to the engine. This was precipitated by a fatigue failure of the metal strap which supported the weight of the oil inlet pipe. The fatigue failure was initiated at an area of mechanical damage on the surface of the support strap, which had been caused by over-tightening of the retaining nut.
Following this accident, the operator introduced additional hand signals to enable the wing walker to inform the pilot of any oil or fuel leaks and for the pilot to inform the walker that he intended to ditch.
