FAA orders urgent inspections of older Boeing 737s

Inspections, repairs now mandatory

In this story:

• Recent incident spurs action
• FAA says public threat minimal
• Inspections cost $1,600 per plane

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 explosion.

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 747s.

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 repairs mandatory.

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.

Related stories:

• FAA proposes fining ValuJet contractor $2.25 million - April 30, 1998
• FAA proposes safety changes to 737s - April 16, 1998
• NTSB wants older 747s checked and rewired - April 7, 1998
• FAA inspectors find no 737 safety problems - February 12, 1998
• NTSB warns of possible fire hazard on 767s - January 27, 1998

Related sites:

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• NTSB - Home Page
• FAA - Federal Aviation Administration

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