Investigation Summary
VX770 was the original Vulcan prototype, a heavily modified airframe that had previously flown with Avon and Sapphire engines before being fitted with Rolls-Royce Conway engines for development testing. On the day of the accident, the crew diverted from a scheduled test flight to perform a display at RAF Syerston. As the pilot executed a high-speed flypast followed by a rolling climb to starboard, the leading edge of the starboard wing failed, leading to the collapse of the main spar. The wing caught fire and the aircraft dove into the ground near a controllers' caravan. The investigation was complicated by conflicting theories regarding the airframe's history and the specific stresses applied during the display. While some investigators suggested the pilot exceeded briefed speed and G-load limits, others pointed to potential pre-existing fatigue damage or vibration issues caused by the high airflow requirements of the Conway engines.
Final Conclusions
The Board of Inquiry (BoI) determined the primary cause was a gross structural failure of the aircraft's main spar. While the BoI did not definitively settle on a single trigger for the collapse, the Technical Officer identified a suspected fatigue failure in a wing attachment forging. A structural analysis report was produced by the Royal Aircraft Establishment in 1960, but it has not been found in the public record.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Main Spar
The primary structural member of the wing; its failure led to the immediate loss of aerodynamic integrity and the subsequent crash.
Rolls-Royce Conway Engines
Experimental bypass engines being tested on the airframe; investigators considered whether their high airflow caused vibrations that contributed to fatigue.
Interesting Facts
- 01VX770 was the first prototype of the Avro Vulcan.
- 02The aircraft was powered by four Rolls-Royce Conway 11 engines at the time of the crash.
- 03The port wing destroyed a fire/rescue Land Rover and a runway controllers' caravan on the ground.
- 04The three ground fatalities were Sergeant E.D. Simpson, Sergeant C. Hanson, and S.A.C. Tonks.
- 05Three others in the vicinity of the Land Rover/ambulance were injured.
- 06The main spar failure was captured on amateur film and photographs.
Safety Actions & Advisories
Fleet Inspection and Speed Restrictions
Following the crash, the remaining Vulcan fleet was subjected to rigorous inspections of the wing leading edges and structural ribs. Operational speed and G-load limits were reinforced for prototype aircraft to prevent structural overstress during test and display flights.
Known Controversies & Unanswered Questions
Undetected Pre-existing Damage
Reference ↗Avro's chief test pilot Tony Blackman argued the aircraft had suffered undetected damage during unofficial aerobatics on previous flights, and that Rolls-Royce maintenance crews were unaware of specific inspection requirements for the leading edges.