The Nimrod Review - Official Documents

Chapter 10A – Nimrod Safety Case: The Facts (Phases 1 and 2)
11. The Nimrod IPT and QinetiQ were content simply to accept that BAE Systems had completed the task
and to agree to ‘sign off’ the final Reports without sufficient inquiry, or asking for any underlying
material, or even carefully reading the final Reports themselves (which would have alerted them
to the substantial proportion of “Open” and “Unclassified” hazards and large amount of work
remaining to be done).
12. Once the Nimrod IPT appreciated the number of “Open” hazards, it subsequently proceeded to
sentence the remaining 43 out of 105 hazards which had been left “Open” by BAE Systems (including
Hazard H73) on a manifestly inadequate, incorrect and unsatisfactory basis.
13. At no stage during the Nimrod Safety Case process did BAE Systems, the Nimrod IPT or QinetiQ, ever
properly identify, assess or address the serious and long-standing catastrophic risk to the Nimrod
fleet represented by the Cross-Feed/SCP duct and the Air-to-Air Refuelling modification.
14. The best opportunity to capture these serious design flaws in the Nimrod fleet, that had lain dormant
for the decades before the accident to the XV230, was squandered.
15. The production of the Nimrod Safety Case is a long, complex and involved story. In order to understand
why it failed, and the precise roles and responsibilities of the organisations and individuals involved,
it is necessary to examine in considerable detail the facts of what took place in the course of its
development during the period 2001 to 2005.
Introduction
BOI findings
10A.1
10A.2
10A.3
The XV230 Board of Inquiry (BOI) found significant errors in the Nimrod Safety Case (NSC):
“…The NSC states that the cross-feed duct is only pressurised during engine start, not
taking into account the lengthy periods it can be pressurized (at a working temperature
of up to 420°C) when feeding the SCP. Furthermore, the NSC notes, as mitigation for
the Zone 614 hazards, the provision of an aircraft fire detection and suppression system:
neither exist within Zone 614. These inaccuracies led to an overly optimistic assessment of
the hazards related to Zone 614, which in turn affected the assessment of the probability
of the loss of an aircraft to an uncontrolled fire/explosion – given as ‘Improbable’… … Had
the NSC’s inaccuracies been noticed earlier, the Board consider that a more intense review
of the hazards concomitant on airframe fuel leaks might have been instigated. Moreover,
the higher risk, which necessarily would have been attributed to such a hazard, would
have required sanction at a higher level of management, or active mitigation, such as not
using the SCP.” 4
In light of the BOI’s findings, the Review conducted a detailed investigation of the NSC, and the history of its
development. The story of the NSC which emerged has proved to be a central part of this Report and holds
important lessons for the future.
This Chapter contains the Review’s findings of fact as to the NSC and its development during the period
2001-2005. These findings of fact are based on months of painstaking work by the Review, piecing together
the story from a large volume of documents, lengthy written submissions from the organisations and individuals
involved and numerous witness interviews. The documents remained incomplete, recollections imperfect and
the parties’ and witnesses’ versions of events were often at odds with each other. I am satisfied, however,
that the following represents an accurate and detailed picture of the long, complex and involved history of
the development of the NSC and its interstices.
4 BOI Report, page 2.23.
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