The Nimrod Review - Official Documents

The Nimrod Review
6.44
6.45
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The dyed water trials from the APU bay and the forward drain of an MRA4 (discussed above) show the manner
in which fuel tracking down the aircraft fuselage will enter compartments, despite the fact that the panels are
flush with the aircraft fuselage and that, in the case of these trials, the aircraft is recently manufactured and
built to modern tolerances. Even 30 minutes after landing, dyed fluid was found “dripping from the tail-cone
bay door”; and when the door was opened it was noted that the fluid had “coated an area in the bay within
approximately one foot all around the door” (see the pink dye in the photographs below).
Pink dye found inside door
Figure 6.7: MRA4 Dyed Fluid Inside Tail Cone Bay Door
Rubber seal
around the
door
The report notes that there was no evidence of fluid pooling in the bay. The amount of fluid released into the
airflow, however, was very small, only 0.4 litres in total, and the distance it had to travel large, namely several
metres from the MRA4 APU bay (in the rear of the wing) to the tail cone bay. By way of contrast, when blowoff
occurs during AAR, the flow rate is very large. It has been calculated to be approximately 120 litres every 10
seconds. 26 Further, as illustrated above, blown-off fuel would only have to track 2.1 metres along the fuselage
skin to reach the SCP fairing. It should be noted that, although the MRA4 is indeed a different aircraft to the
MR2, its fuselage is the original MR2 shape.
Further considerations
6.46
There is clear evidence from the incident in 2006 involving a Nimrod being refulled by an VC10 of fuel flowing
down the outside of the airframe and entering several chambers on the MR2 external to the pressure hull: the
bomb bay, the rear hinged fairing, the dinghy bay, aerial mounts, the self defensive flares chamber and the tail
cone, to name only some. 27 Although the starboard No. 7 Tank Dry Bay was never identified as containing fuel
following this incident, or other similar event, this may well be because this bay is not an area that was examined
regularly prior to the loss of XV230 and, in any event, if fuel had entered the starboard No. 7 Tank Dry Bay lower
26 Approximately 12 household buckets every 10 seconds.
27 Air Incident Report KIN 066/06.