The aircraft had been having ongoing problems with the propeller governor during aerobatics. It had been removed for maintenance on several occasions. After yet more work, the aircraft had undertaken one test flight, and was on its second. The purpose of the second flight was to test the prop/governor under aerobatics. The passenger in the rear cokpit was observing the engine instruments. Ten minutes into the flight the prop governor let go completely, over revving the engine well beyond its limits, and then failed.A forced landing was then attempted. The pilot is an extremely experienced aerobatics pilot, and recently won the Great Tiger Moth Air Race. The passenger has been released from hospital, and the pilot has suffered leg and arm fractures, but is ex
pected to make a full recovery.