What happened
On 22 August 2015, a Hawker Hunter T7, registration G-BXFI, was performing at an air display near Shoreham Airport, West Sussex. During the flight, the aircraft executed a manoeuvre involving both a roll and a vertical component, reaching an inverted position at the peak of the movement. During the subsequent descent, the aircraft failed to regain level flight and struck the westbound carriageless of the A27. The accident resulted in 11 fatalities and one serious injury to the pilot, while the aircraft was destroyed.
The investigation
The AAIB examined the aircraft's maintenance history and the condition of its escape systems. Investigators discovered that the ejection seat and canopy jettison system relied on pyrotechnic cartridges that were past their intended service life. While the maintenance organisation had updated technical records to extend the installation dates, they had not obtained the necessary formal approval from the Civil Aviation Authority (CAA) to do so. Furthermore, the investigation found that the maintenance organisation was operating under a policy that was inconsistent with manufacturer recommendations and regulatory requirements.
Regarding the engine, the investigation looked into the compliance of the Rolls-Royce Avon Mk 122 engine with Mandatory Permit Directive 2001-001. It was found that while the maintenance organisation believed they were meeting requirements through an Alternative Means of Compliance (AMOC), there was no clear evidence of a legally valid AMOC in place for the aircraft from December 2014 onwards.
Findings
- The ejection seat cartridges were time-expired, having exceeded their required installation life.
- The maintenance organisation failed to seek formal CAA approval for extending the life of the pyrotechnic cartridges.
- The aircraft's engine maintenance status regarding the required AMOC was unverified and potentially non-compliant.
- There was a lack of standardised technical publication amendments and a lack of formalised training for civilian personnel maintaining ex-military jet aircraft.
Safety action
Following the accident, the CAA issued a Safety Directive requiring all Hawker Hunter aircraft on the UK civil register to cease all flying operations. The AAIB issued several recommendations, including a requirement for the CAA to review guidance on ejection seats, ensure the continuity of maintenance programmes during ownership transfers, and establish minimum amendment standards for technical publications.