In a Special Bulletin published on 21 December, the Air Accidents Investigation Branch highlighted issues with the use of time-expired ejection seat cartridges in the Hawker Hunter that crashed during the Shoreham airshow – as well as other similar aircraft operated by civilian organisations – and reported that the maintenance organisation responsible for the accident aircraft did not have in place a formal Alternative Means of Compliance for continued airworthiness of its Rolls-Royce Avon 122 engine that had been agreed with the CAA.
The situation is further complicated by the fact that in February 2015 the ejection seat manufacturer ceased support to civilian organisations operating military jets and stopped supplying spare parts. The UK Civil Aviation Authority recommends that aircraft like the Hunter should only be operated with serviceable ejection seats and has stated that ‘it is unlikely that [it] will allow swept-wing aircraft fitted with ejection seats to be flown unless the equipment is fully operational’.
While in 2014 the maintenance organisation had serviced the accident aircraft’s engine in accordance with its proposed Alternative Means of Compliance (AMOC), the company did not appear to have received the CAA’s list of additional information required in applying for that AMOC. The maintenance organisation contacted the CAA later in 2014 regarding the status of its AMOC but there is no record of any response by the authority. The maintenance organisation believed the work it carried out on the aircraft met the requirements of an AMOC: the CAA has indicated that it is trying to clarify the position.
The AAIB makes seven safety recommendations regarding the dissemination of hazard information about pyrotechnic devices, CAA review of its guidance on ejection seats, training, updating and passing on technical information and CAA review of the requirements for Permit to Fly Certificates of Validity. Hawker Hunter aircraft remain grounded as a result of the CAA Safety Directive issued on 25 August in response to the Shoreham accident.