planeandpilotmag.com 11recorder (CVR) captured the flight’s captain,
Ralph Kevorkian, voicing concerns over “a
crazy fuel flow indicator on number four.”
The fuel quantity probe read 640 pounds,
significantly higher than the 300 pounds
recorded by the ground refueler. A test run
on the probe by the NTSB demonstrated that
applying power to one of the wires leading
into the gauge would result in a faulty reading
on the digital display.
MISSILE THEORY
While the NTSB’s findings appeared rea-
sonable on the surface, the public wasn’t
convinced, and many airline pilots scoffed.
According to the naysayers, the only way an
airliner could explode mid-air like that was
as the result of either a terrorist attack or a
military training exercise gone awry. It didn’t
help that, at the time, the country was in a
high state of alert after a series of terrorism-
related events. Substantiating the missile
theory, preliminary testing of three samples
of material from the wreckage indicated the
presence of explosive residue. The NTSB was
unable to conclusively determine the source
of those residues. Additionally, the FBI inter-
viewed 755 witnesses, with hundreds of them
claiming to have seen a “streak of light,” simi-
lar to that of a flare, ascend from the ground
to the aircraft’s location in the sky just prior
to the sighting of the explosion.
Further dampening the NTSB’s findings, a
problem with one of the fuel quantity probes
would have needed to exist in order for them
to be conclusive, yet all of the probes ultimately passed
their tests—including the one with the high reading. The
NTSB also claimed that cracked insulation on electrical
wires likely contributed to the spark that ignited the
explosion, but no cracks were found on the 159 miles of
electrical wire recovered from the scene. That said, 16
miles of wiring was never recovered, and the offending
segment could have been among that missing wire.
METEOROID THEORY
One final theory, and one that’s literally out of this world,
was posed by an amateur geologist in 1997. He believed
that fragments from a large meteoroid exploded in close
proximity to the aircraft shortly after penetrating the
earth’s atmosphere and proposed that the mysterious
streak of light many witnessed was its entry path. He also
claimed that more than 200 holes found in the fuselage,
which the FBI attributed to blast particles originating
from within the aircraft, were the result of high-speed
meteoroid fragments.
THE VERDICT
While it’s the most benign theory, it wasn’t a meteoroid.
For one, witnesses claim that the streak of light came from
below, not from above. Then again, witnesses aren’t the
most reliable source, which is why the missile theory can’t
be substantiated, either. As such, the most probable cause
is the one cited by the NTSB, especially given that this isn’t
the only center fuel tank explosion in a Boeing aircraft. In
1990, the center tank exploded on a Philippine Airlines 737
shortly before takeoff, killing eight. Then, in 2001, Thai
Airways Flight 114, a Boeing 737-400, was destroyed by
a center wing tank explosion prior to boarding, resulting
in a crew fatality. As for the explosive residue found on
the wreckage—the NTSB believes it either came from
contamination when the aircraft was used during the
Gulf War or, most likely, from an explosive-detection
dog-training exercise conducted just a few weeks before
the crash. To prevent further incidents, the FAA issued
safety changes to the fuel pumps and wiring of all Boeing
aircraft with center fuel tanks. PP