I've just come across a detailed account of the Offurt fire:
USAF RC-135V Rivet Joint Oxygen Fire
A US Air Force (USAF) accident investigation has paradoxically determined that a fire that caused of damage in April 2015 was due to a maintenance error but that no human factors were involved.
During investigation it was found that some B-nuts in the oxygen system were finger tight. The USAF report states:
The board president found by preponderance of the evidence that the cause of the mishap was a leak in the high-pressure oxygen system due to poor assembly of the system tubing at depot maintenance. Failure by L3 Communications depot maintenance personnel to tighten a retaining nut connecting a metal oxygen tube to a junction fitting above the galley properly caused an oxygen leak. This leak created a highly flammable oxygen-rich environment that ignited. The resulting fire melted the retaining nut causing the tubing to become detached from the junction fitting, feeding more oxygen to the fire, increasing its size, and causing severe damage to the airframe, galley, and mission equipment onboard the aircraft.
However,
very oddly the report also says:
AFI 91-204, Safety Investigations and Reports, 24 September 2008, Attachment 5, contains the Department of Defense Human Factors Analysis and Classification System [HFACS], which lists potential human factors that can play a role in any mishap. Human factors consider how people’s tools, tasks and working environment systematically influence human performance. There is no evidence that human factors contributed to this mishap. [Emphasis Added]
Do the RAF use L3 for maintenance?