Select Committee on Chinook ZD 576 Report



The Crash

10.  At about 17.59 hours on 2 June 1994 an RAF Chinook Mark 2 helicopter, ZD 576, on a flight from Aldergrove to Inverness, crashed into a cloud-covered hill on the west side of the Mull of Kintyre, a short distance inland of and uphill from the lighthouse. The pilots, Flight Lieutenants Jonathan Tapper and Richard Cook, the other two crewmen and the 25 passengers, who were all senior members of the Northern Ireland security services, were killed.

RAF Board of Inquiry

11.  The RAF immediately convened a Board of Inquiry to investigate the accident, consisting of Wing Commander (now Group Captain) A D Pulford and two Squadron Leaders, one a pilot with experience of helicopters and the other an engineer. Its terms of reference included:

12.  Wing Commander Pulford had never conducted a Board of Inquiry before (Q 5). It is perhaps surprising that an officer with no such experience should have been appointed to conduct an inquiry into an accident with such important and catastrophic consequences - an accident which was described to us by Air Chief Marshal Sir William Wratten as "the largest peace time tragedy that the Royal Air Force had suffered" (Q 437).

13.  Board of Inquiry procedure is governed by rules[2] made under section 135 of the Air Force Act 1955 and by The Queen's Regulations for the RAF, chapter 17. The RAF Manual of Flight Safety AP 3207 published by the Inspectorate of Flight Safety and in force at the time of the accident provided in paragraph 9 of Annex G to Chapter 8 that "only in cases in which there is absolutely no doubt whatsoever should deceased air crew be found negligent".[3]

14.  Paragraph 9 demanded a particularly high standard of proof, higher than is required of the prosecution in a criminal case in the United Kingdom ("beyond reasonable doubt"), and much higher than is required in civil litigation ("on the balance of probabilities"). It was no doubt set so high because deceased aircrew are no longer available to offer their own account of events. We consider that it requires all other plausible explanations for the crash to have been positively excluded. If any such explanations remain possibilities, the standard of proof has not been met. Furthermore, the fact that there is no evidence that an event giving rise to an explanation occurred will not amount to proof positive that it did not if such event could have occurred without leaving evidence of its occurrence or if evidence that it occurred could have been destroyed. Paragraph 9 is no longer in force; since 1997 RAF Boards of Inquiry have not been required or entitled to make findings of negligence.

15.  The investigating board received evidence, oral and written, as well as a very detailed report from the Air Accidents Investigation Branch (AAIB). They concluded that the most probable cause of the accident was the selection of an inappropriate Rate of Climb (ROC) over the Mull. The investigating board did not find that either of the pilots was negligent. The investigating board delivered its report on 3 February 1995.

16.  The next prescribed stage in the RAF Board of Inquiry process is review by the Station Commander. In accordance with the instructions of the Air Officer Commanding No.1 Group, Air Vice Marshal J R Day (as he then was, now Air Chief Marshal Sir John Day, Commander in Chief Headquarters Strike Command), the station commanders at both RAF Aldergrove and RAF Odiham commented on the findings of the investigating board. The former's remarks were brief. The latter, Group Captain P A Crawford, commented at some length. He disagreed with the investigating board as to an inappropriate ROC having been selected and concluded that the reasons for the accident were open to conjecture. He did not find that the pilots were negligent.

17.  The final stages in the RAF Board of Inquiry process are review by the Air Officer Commanding and by the Air Officer Commanding-in-Chief. Air Vice Marshal Day himself accepted the preferred scenario of the investigating board, but concluded that both pilots were negligent to a gross degree. Air Chief Marshal Sir William Wratten, Commander in Chief Strike Command (now retired), agreed with Air Vice Marshal Day.

18.  By kind and exceptional permission of the Secretary of State for Defence, at our request, the narrative report of the Board of Inquiry and the statement to the Board by the AAIB were placed in the public domain on 10 August 2001, and published by the House in November[4]. Other papers of the Board have been shown to us, but remain confidential.

Fatal Accident Inquiry

19.  In early 1996 there took place in the Sheriff Court Paisley a fatal accident inquiry (FAI) under the Fatal Accidents and Sudden Deaths Inquiry (Scotland) Act 1976. In terms of section 6(1)(b) of that Act, the Sheriff, Sir Stephen Young (now Sheriff Principal of Grampian Highlands and Islands), was required to make a determination setting out "the cause or causes of such death and any accident resulting in the death". Sir Stephen conducted an inquiry involving evidence and submissions over some 16 days, with representation as follows:

20.  At the end of 123 pages of very detailed and careful analysis of the evidence[5], the Sheriff concluded,

    "it has not been established to my satisfaction, and on the balance of probabilities, that the cause of the accident was the decision by the crew of ZD 576 to overfly the Mull of Kintyre at cruising speed and their selection for that purpose of an inappropriate rate of climb. It may then be asked what was the cause of the accident. For my part I can only say that I do not know."

21.  It will be noted that the Sheriff was applying the lower standard of proof in civil litigation as required by section 4(7) of the Act of 1976.

22.  The Ministry of Defence (MoD) have suggested[6] that the Sheriff's determination has little relevance to the present inquiry since the FAI had a different objective from the Board of Inquiry. However, section 6(1)(b) makes it clear that the cause of the relevant accident is a subject for his determination, as well as the cause of death. It is perfectly correct that it was not his duty to make a finding of negligence. But it was his duty to make a finding as to the facts which caused the accident. Negligence can only be inferred from facts and if the causative facts are not established there can be no negligence. Thus the Sheriff's inability to determine causative facts is entirely relevant because it means that no facts had emerged from which negligence could have been inferred.

House of Commons Defence Committee

23.  The House of Commons Defence Committee produced a short report on the crash in May 1998[7]. They held only one hearing, with the Minister of State for the Armed Forces (Dr John Reid MP) and officials; they received a small amount of written evidence, including letters from Lord Chalfont and Mr Michael Tapper, the father of one of the deceased pilots.

24.  The Committee did not offer its own view as to the cause of the crash.[8] Instead it considered some of the wider implications of the tragedy: the general performance and reliability of the Chinook Mk 2; Board of Inquiry procedure and the attribution of blame; training in movement between visual and instrument flight; black boxes, and the transport of special passengers. Its report concluded that "great sensitivity" is required in investigating fatal accidents in the armed forces; it acknowledged the efforts of Dr Reid in this regard. It also concluded that lessons learned from this case would help to avoid such controversies in the future.

25.  Though the Defence Committee's report deliberately does not address the question set for us by the House, Dr Reid's testimony contains some highly relevant material. For instance, he enunciated clearly the MoD's position that the negligence of which the pilots were convicted consisted of "perceived failure … to switch from visual flight rules to instrument flight rules … as they approached bad weather"; and he went so far as to say that negligence "would have been deemed to have taken place had the crash not occurred" (Q 765). This proposition does not appear to us to have been advanced by either of the Air Marshals in his written remarks as reviewing officer.

26.  Later, questioned by Menzies Campbell QC MP about the "absolutely no doubt whatsoever" standard of proof, Dr Reid acknowledged that it was "a very high burden of proof". He declined to be drawn into philosophical debate as to whether absolute certainty is ever achievable, offering instead the following test: "have we ruled out the possibility, on the basis of the evidence in front of us, that there was another possibility here?" (Q 917).

27.  The Government responded to the report in October 1998.[9]

House of Commons Public Accounts Committee

28.  The House of Commons Public Accounts Committee (PAC) reported in November 2000 on Ministry of Defence: Acceptance of the Chinook Mk 2 helicopter[10]. Unlike the Defence Committee, the PAC considered the verdict of the Board of Inquiry. They found it "unsustainable", and recommended that it should be set aside. They accused the MoD of "unwarrantable arrogance" in standing by it, particularly in the light of the inconclusive outcome of the Fatal Accident Inquiry, working as noted above to the lower standard of proof of "balance of probabilities".

29.  The PAC took oral evidence from the National Audit Office, the Treasury, and officials from the MoD led by the Permanent Secretary. Written evidence included memoranda from Mr Malcolm Perks, an expert witness for MoD in a legal action in 1994-95 against the US firm which developed the Chinook Mk 2 Full Authority Digital Engine Control (FADEC) computerised fuel control system; and from the periodical Computer Weekly.

30.  As the Committee charged with examining public spending, the PAC naturally took as its starting point the procurement of the upgrade which gave the RAF its Chinook Mk 2 fleet. It found this to have been flawed, particularly in respect of the software of the FADEC system. In 1994 the FADEC software was both faulty and "unverifiable": it defied independent evaluation by either the Aircraft and Armament Experimental Establishment (A&AEE) at Boscombe Down or EDS-SCICON, a firm specialising in testing software.

31.  The PAC's doubts about FADEC led to its rejection of the finding of the Board of Inquiry, by two different routes. First, the Committee considered that a FADEC fault or other technical malfunction on ZD 576 was a real possibility, and that there was not enough evidence to rule this out, at least as a "potential" or "contributory" cause of the crash. In its view, "negligence should only be found where it can be positively identified to have been the cause of a crash … it is impossible to prove gross negligence in the case of ZD 576". Second, it cast doubt on the "perceived objectivity" of the reviewing officers (though it did not impugn their integrity), on the grounds that they were "also responsible for the operational management of the Chinook fleet and minimising the disruption to support helicopter capability caused by the problematic introduction into service of the Mark 2".

32.  The Government's response[11] rejected the Committee's conclusions. It denied that the FADEC software was poorly written and explained why Boscombe Down had had difficulty verifying it. It gave reasons why the Board ruled out a FADEC malfunction: both engines were running at the time of the crash, and the one digital engine control unit (DECU) which survived the impact had no trace of a fault or abnormality. It summarised the evidence underpinning the finding of negligence:

  • the weather;
  • the navigational information available to the pilots;
  • the fact that they had taken no avoiding action before or at the time of an action ("the way point change" - see para 53 below) taken 1.75km away from impact which seemed to indicate that the aircraft was under control;
  • the absence of evidence that the crash was due to technical malfunction.

33.  The response declined to prefer the Sheriff's verdict to that of the Board. It insisted that the reviewing officers had met the high standard of proof required, and reached "an honest conclusion based upon the evidence" which would not be set aside without new evidence. It also insisted that "it is appropriate for the chain of command to be responsible for investigating accidents".

The House of Lords inquiry

34.  On 5 March 2001, shortly before the Government responded to the PAC, Lord Chalfont moved in the House of Lords "that … the Liaison Committee[12] should consider the appointment of a Select Committee to consider all the circumstances surrounding the crash of Chinook helicopter ZD 576 on the Mull of Kintyre on 2 June 1994". The Government did not oppose this motion; indeed Baroness Symons of Vernham Dean, speaking as Minister of State at the MoD, appeared to give it some encouragement by observing that "the Air Marshals will then be able to explain properly in their own words to the Select Committee why they reached the conclusions that they did, something they have not been able to do properly before". The motion was agreed to without a division.

35.  The Liaison Committee duly considered the matter, taking evidence from Baroness Symons and Lord Chalfont. By then the PAC had received the Government's response to their report, and it instructed its then Chairman, David Davis MP, to write to the Liaison Committee commenting on it in critical terms. This letter, and the other evidence, are printed with the Liaison Committee's report.[13]

36.  The report dealt first with Lord Chalfont's proposal for a committee "to consider all the circumstances". It advised against this, on the grounds that it "would not be practical: it would take too long, and a House of Lords Committee would not be equipped to undertake it".

37.  The Liaison Committee then considered the alternative proposal of a review limited to the justification for the decision of reviewing officers. Some members favoured this course. A majority, however, did not, for the following reasons:

    (a)  To re-examine all the evidence would take a long time, and would still not put a Select Committee in a position to make a better judgment than experienced and senior professionals.

    (b)  Whatever its conclusions, a Select Committee Report would be unlikely to put an end to the controversy.

    (c)  Select Committees are a good vehicle for the examination of issues of public policy, but are not equipped to replicate the function of the higher courts in addressing alleged miscarriages of justice.

38.  The Liaison Committee accordingly recommended against the appointment of a Select Committee. However, when on 30 April the Chairman of Committees invited the House to accept the report, Lord Chalfont moved the following amendment:

    "this House rejects the recommendations of the Liaison Committee and appoints a Select Committee of five members to consider the justification for the finding of those reviewing the conclusions of the RAF Board of Inquiry that both pilots of the Chinook helicopter ZD 576 which crashed on the Mull of Kintyre on 2 June 1994 were negligent".

39.  The then Leader of the Liberal Democrat peers, Lord Rodgers of Quarry Bank, a member of the Liaison Committee at that time, had tabled an alternative to Lord Chalfont's amendment, in the form of a motion to resolve that

    "this House calls on Her Majesty's Government to set up an independent review of the conclusions of the Board of Inquiry into the crash of Chinook ZD 576 on the Mull of Kintyre on 2 June 1994".

40.  For the Government, Baroness Symons indicated that Lord Rodgers' proposal was unacceptable, since the Government acknowledged no reason why they should expose the Board of Inquiry's judgment to review. She added that if the Liaison Committee were to reconsider the question and to recommend a committee along the lines now advocated by Lord Chalfont, the Government would not resist it. The Chairman of Committees indicated, however, that the Liaison Committee was highly unlikely to change its mind. The House therefore divided on Lord Chalfont's amendment, which was agreed to by 132 votes to 106.[14] Lord Rodgers' motion was not moved.

41.  In short, the gestation of the Committee whose report this is was highly unusual. We are very conscious that a majority on the Liaison Committee, and a large minority of members of the House, believed that our Committee should not be set up at all. Set up we were, however, on 2 July 2001, and we have done our best to fulfil the remit given to us by the House.

2   Board of Inquiry (Air Force) Rules 1956 as amended. Back

3   Annex G as in force at the time is printed in HL Paper 25(ii), p 81. Back

4   HL Paper 25(i) 2001-02, published by TSO, ISBN 0 10 442022 7, £18.50. Full text on the Parliament website Back

5   Published in full in HL Paper 25(ii). Back

6   E.g. in their response to the Commons Public Accounts Committee, para 30 - see fn 11 below. Back

7   Lessons of the Chinook crash on the Mull of Kintyre, 4th report 1997-98, HC 611. Back

8   "… we concluded that it would be helpful to clarify in a public forum some of the conflicting messages about the possible causes of the crash, and to put these into a wider context of concerns about the safety of the Chinook fleet. However, … it was not our intention to become a further court of appeal, and our inquiry and this report seeks neither to challenge nor endorse the findings of previous inquiries into the crash" (para 3). Back

9   Defence Committee 4th Report 1997-98, HC 1109. Back

10   45th Report 1999-2000, HC 975. Back

11   Treasury Minute on the 44th and 45th reports from the PAC 1999-2000, Cm 5078, March 2001. Back

12   One of the functions of the House of Lords Liaison Committee is "to consider requests for ad hoc committees". Back

13   Proposal for a Select Committee on the crash of Chinook helicopter ZD 576 on the Mull of Kintyre on 2 June 1994, 2nd Report 2000-01, HL Paper 67. Back

14   Of the members of this Committee, Lord Bowness and Lord Hooson voted for Lord Chalfont's amendment; Lord Brennan voted against it; Lord Jauncey of Tullichettle and Lord Tombs did not vote. Back

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