Select Committee on Public Accounts Minutes of Evidence

Letter to the Chairman of the Committee from Mr Martin O'Neill, MP, the Rt Hon James Arbuthnot, MP and Mr Menzies Campbell, MP (PAC 1999-2000/86)

  We understand the Public Accounts Committee is due to discuss the National Audit Office Report "Accepting equipment off-contract and into service" on 8 March.

  There are two matters relating to this report we would be grateful to bring to the Committee's attention.

  1.  Acceptance of the FADEC system into service on the Chinook Mk2,

  2.  The possible role of FADEC in the crash of RAF Chinook ZD576.


  The contract to upgrade the Chinook Mk1 in 1990 included a new computerised engine control system known as FADEC. It controlled the fuel output to the engines using highly sophisticated software.

  Boscombe Down, the MoD's testing centre, was responsible for checking or "reading" the software to ensure it was built to defence standards. Unfortunately, it found the software "unacceptable". The MoD then commissioned EDS-SCICON to make an independent assessment of the software. However, after finding more than 485 anomalies in just 18 per cent of the code, they stopped. They suggested it needed re-writing.

  Textron Lycoming, the manufacturer of FADEC, reassured the MoD that whilst the anomalies were undesirable, they did not represent an airworthiness concern. However, it later emerged, that at the time the MoD was relying on these assurances, they were suing Textron Lycoming on the grounds they failed to use the skill contractually required in the design development, manufacture and testing of the FADEC system.

  Nevertheless, the Chinook Mk2 was brought into operational service in November 1993. Soon after, pilots experienced serious FADEC-related problems. Engines would cut out or suddenly run out of control. Sometimes these problems left no trace. After one such unexplained incident in March 1994, flight trials were suspended at Boscombe Down for six weeks and again on 1 June 1994.

  Throughout this period, the aircraft was kept in operational service. A Chinook Mk2 pilot, Lt Ian Kingston, later recalled "it was quite a concern to us . . . [but] we were told to get on with it.

  MoD subsequently acknowledged that during the period between February 1994 and July 1994 the Chinook Mk2 suffered from a "series of problems . . . many of which were traced eventually back to software design and systems integration problems". (Internal MoD Memo, 11 January 1995, Capt Brougham, Procurement Executive).

  It was during this period that RAF Chinook ZD576 crashed on the Mull of Kintyre.


  The fatal crash involving RAF Chinook ZD576 happened on 2 June, the day after Boscombe Down suspended flight trials for the second time. In the three weeks prior to the crash, this same aircraft had suffered 3 FADEC related incidents, including one that necessitated an engine being replaced.

  The investigation following the accident found no evidence of technical malfunction that could have contributed towards the crash. However with regard to FADEC, the Board of Inquiry concluded, "nevertheless, an unforeseen technical malfunction, which would not necessarily have left any physical evidence, remained a possibility and could not be ruled out". (RAF Board of Inquiry, p2-18).

  Despite the possibility of such a malfunction and other possible causes identified by the Inquiry, both pilots were judged to be grossly negligent. For a finding of negligence to be made, however, the Inquiry was required to satisfy RAF Regulation AP3207 which states "only in cases in which there is absolutely no doubt whatsoever should decreased aircrew be found negligent".

  There is no proof that FADEC caused the crash; nor is there any proof that it did not. But there is persuasive evidence that the computer software problems had not been resolved before ZD576 flew into the Mull of Kintyre. This raises doubts that all responsibility for the crash belongs to the pilots.

  We would be grateful if the Committee would investigate these matters further.

Martin O'Neill MP
James Arbuthnot MP
Menzies Campbell MP

28 February 2000

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