The Nimrod Review - Official Documents

The Nimrod Review
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No significant challenges to the BOI’s findings
3.16
3.17
3.18
3.19
There have been few challenges to the BOI’s basic findings whether from the Nimrod community or elsewhere.
In a letter to the Review dated 22 April 2008, BAE Systems stated that “to date we have no reason to contradict
the fundamental conclusions of the [BOI] report”. BAE Systems is not alone in this position. Indeed, since
publication of the BOI’s report, there has been no real challenge made to the BOI’s conclusion that an exposed
element of the aircraft’s Cross-Feed/SCP pipe work was the most likely ignition source for the fire. I explain in
detail in Chapter 4 why I consider that conclusion to be plainly correct.
Some differing opinions have been expressed, however, in relation to the most probable fuel source for the
fire. Whilst agreeing with the BOI’s overall conclusions, BAE Systems explained to the Review the reasons why it
considered the source of fuel was, on balance, more likely to have been a fuel seal failure than AAR blow-off,
rather than the two being equally probable as the BOI found. I consider these issues in detail in Chapters 5 and
6. I also explain why other theories as to the fuel sources, notably that of Mr Andrew Walker, the Oxfordshire
Assistant Deputy Coroner who conducted the Inquest (see Chapter 16), and Mr Graham Bell (brother of Flight
Sergeant Gerard Bell, deceased), can be dismissed as not credible and why the BOI are correct in their analysis
as to the two most probable sources of fuel. I also make findings as to which is the more probable of the two.
In view of the fact that BOI findings are a foundation for this Review, I contacted the United States Air Force
Safety Center (AFSC) and asked them to conduct a review of the BOI report. The AFSC has a world-class
reputation and its personnel are very experienced in carrying out military aircraft accident investigations. The
AFSC has a wide-ranging remit to promote aviation safety. To quote from its mission statement:
“The Air Force Safety Center develops and manages Air Force mishap prevention programs
and the Nuclear Surety Program. It develops regulatory guidance, provides technical
assistance in the flight, ground and weapons and space safety disciplines, and maintains
the Air Force data base for all safety mishaps. It oversees all major command mishap
investigations and evaluates corrective actions for applicability and implementation Air Force
wide. It also develops and directs safety education programs for all safety disciplines.”
I am grateful for the assistance of the AFSC and that of the Executive Director, William C. Redmond. The AFSC
dispatched a team of four senior staff to RAF Kinloss, where they spent time examining the Nimrod aircraft and
considering the BOI report. I also travelled to the US to consult them on this aspect and other aspects of flight
safety. The AFSC team carried out further significant additional work in the US and have conducted a detailed,
meticulous and comprehensive review of the BOI.
3.20 The conclusions of the AFSC were that the XV230 BOI “ was thorough and professional”, “meticulous in gathering
and reviewing available evidence” and “demonstrated exceptional investigative diligence”. 20 Importantly, the
AFSC agreed with the BOI’s deduction as to point of ignition and endorses the BOI’s conclusion as to the three
potential sources of fuel. The difference of emphasis between the AFSC and the BOI is as to the relative likelihood
of the two most probable sources of fuel for the fire on XV230 as found by the BOI: fuel seal failure or overflow
from No. 1 tank. The BOI decided these two sources were equally likely, whereas, the AFSC believed that the
former was more likely than the latter. Nonetheless, the AFSC made clear that all other postulated sources of
fuel are much less likely than these two. (As I make clear in Chapter 5 however, new evidence has since come
to light which points to the most probable source of fuel). The only minor criticism that the AFSC made of the
BOI’s analysis of this area is that experimental evidence could have been used to possibly substantiate the BOI
theory concerning the migration path of fuel which may have overflowed from No. 1 fuel tank.
3.21 As the AFSC made clear, “ different investigative agencies reviewing the same evidence may reach somewhat
different conclusions”. 21 In explaining the precise sequence of propagation of the fire on XV230, the AFSC
also took a slightly different view to the BOI, but not one that has a material effect on the BOI’s conclusions.
Essentially, the difference in interpretation centres on the ability of No. 7 fuel tank to withstand the effects of
thermal heating. The BOI’s combustion experts determined that the final explosion reported by eyewitnesses
20 AFSC Response to Questions from the Nimrod Review, pages 1 and 2.
21 Ibid, page 5.