FAA orders urgent inspections of older Boeing 737s
Inspections, repairs now mandatory
In this story:
May 7, 1998
Web posted at: 5:13 p.m. EDT (2113 GMT)
WASHINGTON (CNN) -- The Federal Aviation Administration on
Thursday ordered the urgent inspection of hundreds of older
Boeing 737 planes for possible wiring hazards, after an
incident this week indicated the kind of electrical arcing
suspected of causing the explosion of TWA Flight 800.
FAA and Boeing officials concluded that two, pin-sized holes
in a pipe carrying electrical wires through a fuel tank on
the wing of a Continental Airlines plane were caused by
electrical arcing within that pipe.
Arcing in the central fuel tank is suspected of downing the
TWA jumbo jet, a Boeing 747, off Long Island on July 17,
1996, killing all 230 people aboard.
The directive, which requires compliance within seven days or
five flight hours, whichever comes later, applies to 152
Boeing 737-100 and -200 models. If repairs are necessary,
they could take the plane out of service for 15 hours, but
officials for all three airlines told CNN they expect no
significant flight disruptions.
Continental and two other major airlines, United and
Southwest, will be most affected by the order. They have 348
older 737s worldwide -- including 152 domestic -- that must
be checked within the next week.
An explosion was created in this Boeing 747 as part of the TWA investigation
The FAA also announced it is giving the operators of Boeing
747 and 767 aircraft 60 days to do similar inspections.
"The FAA actions are intended to detect and correct chafing
of wire insulation inside conduits installed in the fuel
tanks of these Boeing aircraft," the order said. "Chafing
could expose the wires and potentially lead to electrical
arcing that might penetrate the conduit, resulting in a
possible fire or explosion of the fuel tank."
FAA says public threat minimal
FAA officials said there was some urgency in their
directives, but said they had concluded that there was
minimal threat to the flying public if the inspections and
necessary repairs were completed within the required period.
"With the seven-day period we have, and the daily feedback
that we're going to be getting and the ability that we have
to instantaneously almost change the airworthiness directive
when we want to, I think we've taken fairly conservative
action and fairly aggressive action to deal with an issue,"
said Thomas McSweeny, FAA director of aircraft certification.
The action stems from an ongoing investigation into the TWA
disaster. While investigators still have not determined what
caused the crash, they suspect that electricity from wiring
around the Boeing 747's center fuel tank may have sparked the
Boeing recently notified the FAA that it found three 737s
with "a high degree of wear" on the protective Teflon sleeves
and in-tank wires, the FAA said, prompting the agency "to
raise the safety bar on aircraft fuel tanks," the FAA said.
Initial suspicions that a bomb or missile caused the
explosion on TWA Flight 800 were ruled out November 17. Nine
days later, the FAA issued an "airworthiness directive"
ordering the immediate inspection of the wiring of older
Inspections cost $1,600 per plane
In early April, the National Transportation Safety Board
recommended sweeping inspections and design changes in the
wiring of Boeing 747s like TWA Flight 800, and changes on
other Boeing 707s and C-130 military tranport planes as well.
In mid-April, the FAA proposed changes to the wiring and vent
systems of older Boeing 737s, which are similar to those on
the 747s. The order issued Thursday makes inspections and
The inspections of the affected Boeing 737-100 and 737-200
models with more than 50,000 flying hours will cost an
estimated $1,600 per plane. A schedule for Boeing 737s with
fewer than 50,000 hours will be announced later.
United Airlines owns 44 of the affected 737s, Continental has
21 and Southwest Airlines flies 30 of the planes, according
to the FAA.
The FAA said the other 57 planes are owned and operated by 26
other air carriers and charter companies.
The inspections of the 264 Boeing 747s and 231 Boeing 767s
registered in the United States that must be completed within
60 days should cost about $60 per aircraft.