The Nimrod Review - Official Documents

The Nimrod Review
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or destruction of a multitude of hydraulic pipeline fairleads, damage to the front face of the No. 7 fuel tank,
extensive damage and melting to numerous fuel seals, damage inside the bomb bay and damage to the Rib
1 and rear spar temperature indicator looms. As the XV230 BOI observed, “Although this particular pipe was
replaced throughout the Nimrod fleet, and is thus unlikely to have contributed to XV230’s loss, the incident
illustrates the extensive effects of heat damage concomitant on the spread of hot gases within this area.” 16 A
recommendation was made by the XV227 UI to incorporate a hot air leak detection system, to ensure that all
possible duct failures were covered. The recommendation was not enacted because the IPT believed that such
a modification was not practicable in view of the Nimrod’s Out-of-Service Date (OSD).
8.34 I explain in Chapter 7 why, in my view, the loss of XV230 was not caused by a hot air leak of the type experienced
on XV227 and why the fitting of the hot air leak warning system proposed by the XV227 UI would not have
made any difference to the outcome of XV230’s fire. It must nonetheless be recognised that the XV227 incident
(and the earlier history of corrosion problems experienced with the hot air ducts, discussed in Chapter 7)
presented an opportunity, which was missed, properly to assess the risks posed to the Nimrod aircraft by the
hot air duct system (see Chapter 4). As one Nimrod line maintenance engineer put it to the Review, there is no
doubt that XV227 should have been a “wake up call” for everyone, in particular to those compiling the NSC
(see further Chapter 11). It is highly regrettable that it was not.
8.35
8.36
8.37
The manner in which the subsequent actions related to the XV227 investigation were handled betrays a worrying
lack of ‘corporate memory’ on the part of both BAE Systems and the Nimrod IPT. There seemed to be collective
amnesia about the fact that Nimrod bleed-air ducts had suffered from systemic corrosion and fatigue problems
since the early 1980s onwards. This problem seems to have been slowly ‘forgotten’; as time wore on the original
resolve to replace all of the ducts ebbed. Indeed, whilst the documentary evidence provided to the Review was
replete with references to corrosion in the ducts in the 1980s, 17 such references disappear almost entirely in the
1990s and the issue did not resurface again until BAE Systems reviewed its earlier reports of 1982 and 1984
when preparing its report of June 2005. It is particularly striking, as I discuss further in Chapter 11, that the NSC
prepared in the meantime does not contain a single reference to any of BAE Systems’ earlier reports, or indeed
even to the existence of the earlier corrosion problems experienced with the ducts.
XV227 also, in my view, again illustrates a worrying tendency on the part of both the Nimrod IPT and BAE
Systems, to look at problems in isolation, and in their own particular compartments, rather than taking a
more holistic view. As BAE Systems correctly identified in the 1980s, the corrosion problem with the ducts was
systemic. Notwithstanding BAE Systems’ advice to this effect, however, when incidents occurred, they tended
to be approached as ‘one-off’, without anybody delving back into the earlier history. Indeed, even in respect of
the XV227 incident itself, the IPT Leader, Group Captain (now Air Commodore) George Baber stated in a letter
to BAE Systems, dated 3 March 2006, that: “following the failure of the Secondary Cooling Pack (SCP) duct the
hazard was still assessed as an Incredible risk as it was considered to be a one off event”. 18
Of course, the real tragedy of the XV227 incident is that the opportunity to appreciate the general fire hazard
represented by the SCP was missed. I refer elsewhere in this Report to the dangers of embedded design defects,
such as those arising in the case of the SCP. Over the years, a number of very competent and experienced
engineers looked into, or worked in, the No. 7 Tank Dry Bay and failed to spot the (with hindsight) obvious
risk presented by the close proximity of the SCP duct and fuel pipes in that area. It was the elephant in the
room, which nobody saw because nobody was looking for it. The XV227 incident, however, directly focused
the attention of the Nimrod IPT, BAE Systems and indeed all those working on the Nimrod on the potential
risks presented by a failure of the SCP duct. It is clear both from the initial fault reports and the UI report into
the incident (see Chapter 7) that it was widely appreciated that, as a result of the leak from the hot air pipe,
significant damage had been sustained not only to the primary structure of the aircraft, but also to fuel seals in
the adjacent pipelines. Nonetheless, no real thought appears to have been given to the potential for any leaking
fuel as a result of such damage meeting a source of ignition; either the ruptured duct itself or another area of
the hot air system. Indeed, it may be said to constitute a short mental step to go from registering the risk of a
16 BOI Report, Exhibit E [E-2].
17 For example, the minutes of the meetings of the Nimrod Structural Integrity Working Party show that the problem of the cracking of the ducts was
regularly discussed at the meetings between 1980 and 1982.
18 DLO(Strike)(Wyt) 512725/27/6/1.