Germany's Lufthansa airline briefly grounded 26 Boeing 747-400 long-haul aircraft for safety inspections and repairs Tuesday
after discovering cracks in lines that carry firefighting agents to the turbine engines.
The discovery prompted the Federal Aviation Administration in Washington to announce plans for similar inspections on Boeing 747s in the United States. Spokesman Eliot Brenner said the order was likely to allow the airlines time to do the work rather than requiring immediate action.
Lines had to be replaced on eight of the 747-400 models, and all the jets later were returned to service, Deutsche Lufthansa spokeswoman Sigrid Baeumer said Tuesday evening. A precautionary inspection of six Boeing 747-200s owned by Lufthansa uncovered no problems, she said.
The cracked lines were discovered early in the day during routine maintenance of one of the 747-400s, and Lufthansa decided to ground all the aircraft until they were inspected and their copper lines replaced.
Baeumer said it was the first time the airline had such a problem with the copper tubing, which is commonly used in aeronautics.
The grounding forced cancellation of a flight to Tokyo, and passengers were sent on a later flight from Frankfurt. All but five of the airline's 747-400s were in Germany; the others were based in Bangkok, Thailand; Buenos Aires, Argentina; Cape Town, South Africa; Manila, Philippines; and Singapore.
Lufthansa said it immediately informed Boeing Co. of the problem.
Franzjosef Darius, a spokesman for Boeing in Hamburg, said his company was grateful for Lufthansa's quick reaction.
Darius said he was unaware of other airlines reporting similar problems, adding that fires in the turbine engines were rare but that the lines in question were critical to dousing any blaze.
In Seattle, Boeing spokeswoman Debbie Nomaguchi said the company issued a service bulletin for the same fire-extinguisher tubing in 1995, advising airlines flying 747-400s to replace it because of problems similar to those reported by Lufthansa.
``We are still working to determine if this is an isolated case or if it's fleet-wide,'' affecting all 747-400s, she said.
Lufthansa spokeswoman Karin Weber said the airline replaced the tubing in 1995 with new Boeing parts, but that the problem was with the new tubing.
``Boeing is in process of sending out an all-operator message'' to advise its 747 customers that Lufthansa found cracked tubes in several planes, company spokesman Gary Lesser in Seattle said, prior to the FAA announcement.
Boeing customers are being asked to advise the company if they have found any similar problems while inspecting their aircraft, he said.
The 747s in Germany have General Electric engines while most of those in the United States are powered by Pratt & Whitney, said Brenner, the FAA spokesman.
He said that the engines have a four-step fire protection system, of which the fire extinguisher bottles are the last step.
There is also a fuel cutoff, fuel drain and firewall protecting the airplane, he said.
Brenner said the FAA is working with Boeing and United Airlines, a major operator of the type, to gather information on the planes.
The 747-400 is a bigger, longer-range version of Boeing's 747, with a capacity of 416 to 524 passengers and a range of about 8,400 miles. First flown in 1989, the 747-400 family includes four models.
The 747-200, depending on variable seating arrangement, carries between 300 and 368 passengers.