 The investigation found that fuel most probably travelled from a fuel tank blow-off valve on the starboard side of the lower-forward fuselage into an aft bay near the root of the starboard wing which contained hot air ducting pipes, where it saturated compressed insulation contained within a shrouding, holding the fuel against a hot air pipe until it reached auto-ignition temperature and caught fire.The fire was first noted when smoke accumulated in the bomb-bay, leading the pilot to report a fire in his bomb-bay.He tried to reach Kandahar air base, taking the aircraft down from in 90 seconds.