The Nimrod Review - Official Documents

The Nimrod Review
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because Nimrods were only refuelled on the ground by bowsers. In making these pipes “live”, the
AAR modification introduced a significant new element to the risk of fire because of their close
proximity to the hot Cross-Feed/SCP duct. (See further Chapter 6).
Why were the design flaws not spotted for decades?
19. The juxtaposition of hot ducting and fuel pipes in both No. 7 Tank Dry Bays, and the threat from
fuel from the starboard No. 1 tank blow-off valve entering the fuselage, represented serious, everpresent
and, once pointed out, obvious risks to the Nimrod fleet for several decades. The question
is: why then did nobody spot these design flaws during the intervening years? Many competent,
hard-working and dedicated engineers had worked on the aircraft; and, whilst No. 7 Tank Dry
Bay was not frequently examined during maintenance, numerous trained eyes would have looked
inside these bays and observed fuel pipes and couplings within inches of hot ducting. The answer
lies in an understandable assumption by operators that aircraft are designed properly and delivered
in an airworthy condition. The best opportunity to capture these flaws, during the Nimrod Safety
Case produced between 2001 and 2005, was lost (see Chapter 10).
20. This case starkly illustrates how dangerous such fundamental “embedded” design defects can be,
and how important it is not to make blanket assumptions about safety.
Conclusion
21. BAE Systems designed, manufactured and installed both the SCP duct and the AAR capability for
the Nimrod, but failed properly to understand or assess the risks inherent in their designs and
modifications.