FAA Proposes Wider Checks of 747s for Cracks

The Federal Aviation Administration, concerned about the potential for structural cracks in older 747 airplanes, proposed Tuesday that airlines flying Boeing jumbo jets be required to inspect the front sections of these planes thoroughly.

The agency said that its proposal for an airworthiness directive requiring “repetitive” inspections, which is expected to cover 160 planes, was prompted by a recent finding “of numerous body frame structure cracks in the nose of the fuselage” of 747s. As of March 21, the FAA said, more than 30 instances involving cracking have been found.

Although FAA spokesman Fred Farrar said that “there is no immediate danger,” the potential for disaster was made clear by the agency’s proposal, which stated that “failure of the structure could lead to sudden decompression.”

Caused by Pressurization

The cracking was attributed to the stress of repeated cabin pressurization, the agency said, and occurred on planes that had made between 6,450 and 20,002 flights.

The FAA will accept public comments on the proposal until Aug. 22, after which the agency will decide on the final rule it will issue.

Last January, the FAA ordered inspections for cracks on Boeing 747s that had made 10,000 or more flights. In February, the agency ordered an emergency directive for expanded inspections after cracks were found in 747 fuselages in planes operated by Pan American World Airways, TWA and British Airways.

The latest FAA proposal would expand such inspections even further to other parts of the nose fuselage because cracking has been found “in areas other than those required to be inspected” by the earlier order.

Advisory Issued in May

In May, Boeing issued a service bulletin describing procedures for inspecting the nose section of the airplanes and for repairing cracks.

John Wheeler, spokesman for the Boeing Commercial Airplane Co. said that the FAA proposal is essentially based on that advisory.

However, he said, “it’s certainly not a critical safety item. If it were, they (FAA officials) would have issued an immediate directive.”

Wheeler said that the proposed rule is aimed at older planes, those that have made at least 8,000 flights and have been in service for about 9 1/2 years. The order includes the bulk of 747s flown by U.S. airlines.

“This is a fact of life in the airplane business,” he added. “As the airplanes age they can develop cracking in some of the structure. They are designed to fly safely with that cracking, which is designed to be detected during routine maintenance.”

No Flight Until Repaired

Inspection schedules would depend on the number of flights that the 747s have made. The checks would include top, sides and bottom parts of the front fuselage section extending from the nose to a point beyond the first passenger entry door.

For example, with planes that have made 8,000 flights, the FAA proposal requires airlines to perform a visual or X-ray inspection on parts of the nose section within the next 600 flights. Aircraft with more than 14,000 landings will have to be inspected within the next 100 landings. Any cracks would have to be repaired or replaced before further flight.