When the aircraft landed and came to a full stop, it
initially had a small fire on its wing that could have
been putout. But because fire trucks could not get to
the aircraft because the corn field was muddy and not
accessible by vehicle as a result of rain fall the night
before the aircraft continued to burn and eventually was
consumed by fire.
The weekend before this flight the WWII vintage Boeing
B-17G had undergone maintenance for a fuel leak, the
leak was repaired and a final inspection the morning of
the flight there was no indication of a fuel leak. A
post accident examination of the aircraft showed that
the C-channel installed as part of the number 1 main
fuel tank repair earlier in the week was partially
separated and a longitudinal fatigue crack along the
The NTSB indicated the fatigue nature of the crack was
consistent with a progressive failure along the fuel
tank seam that existed before the accident flight and
was separate from the damage sustained in the emergency
landing and post-landing fire. The repair earlier in the
week attempted to seal the leak but did not address the
existing crack itself.
fact, the length of the crack observed at the time of
the repair was about one-half the length of the crack
noted during the post-accident examination, suggesting
that the crack progressed rapidly during the course of
the accident flight.
Because the repaired fuel tank was positioned within the
open wing structure, a fuel leak of significant volume
would have readily vaporized, producing a flammable fuel
vapor/air mixture. Although the exact ignition source
could not be determined due to the fire damage, it is
likely that the fuel vapor and liquid fuel encountered
hot surfaces from nearby engine components, which
initiated the in-flight fire.
The National Transportation Safety Board determines the
probable cause(s) of this accident to be an inadequate
repair of the fuel tank that allowed the fuel leak to
continue, ultimately resulting in an in-flight fire.