On the day of the accident VX770 was flying from the Rolls-Royce airfield at Hucknall, with four crew on board, including a flight test engineer from Avro, carrying out performance tests on the Rolls-Royce Conway engines that had been fitted in place of the Sapphires and Avons originally fitted. During the course of the test-flight VX770 diverted to RAF Syerston to participate in the Battle of Britain day air show.
Accident
The Vulcan flew along runway 07 then started a rolling climb to starboard. During this manoeuvre the starboard wing disintegrated, resulting in a collapse of the main spar and wing structure. The Vulcan went into a dive with the starboard wing on fire and struck the ground. Three occupants of a controllers' caravan were killed by debris, all four of the Vulcan crew were also killed. Three servicemen who were in an ambulance were also injured by debris from the crash.
Cause
The official primary cause for the accident was a gross structural failure of the aircraft's main spar, which was confirmed by amateur footage, photographs and eyewitness accounts. The reason for the failure was not determined by the Board of Inquiry, but it was suggested by an accident investigator called in by Rolls Royce that the main cause was that the pilot, upon performing the planned aerobatic display, exceeded the prototype's briefed speed and turning rate limits. The accident investigator submitted a statement to the BoI, but did not give evidence under oath. The BoI was apparently not informed that the aircraft manufacturer considered the basis for the statement to be invalid. The Technical Officer of the Board of Inquiry identified a suspected fatigue failure of the inboard arm of the front bottom wing attachment main forging, and suggested vibration from the high airflow volumes required by the RR Conway 11 engines as a possible cause. The Royal Aircraft Establishment carried out a structural analysis of the wreckage and produced a report on 21 April 1960, but no copy has been found in the public record. Tony Blackman argues that the maintenance crew failed to properly inspect the aircraft for known issues with stress damage to the aircraft's leading edges and structural ribs, which had been observed in another prototype he had flown earlier.
