Airlines this week found four Boeing 737s with loose bolts in the wing that could have led to a fuel leak and fire, prompting federal officials on Wednesday to order speedier inspections of the popular aircraft.
The inspections were ordered by the Federal Aviation Administration after investigators in Japan found that a misplaced bolt likely triggered a blaze that destroyed a China Airlines 737 on Aug. 20 in Okinawa, the agency said. All 165 people escaped before a fireball engulfed the jet.
The discovery of more problems in the Next-Generation 737s — updated models of the jet built after 1998 — prompted the FAA to order airlines to complete inspections within 10 days instead of the original 24-day period, according to an Emergency Airworthiness Directive issued by the agency.
In four cases, bolts in the slat mechanism on the wing had become dislodged, said FAA spokeswoman Laura Brown. In one instance, the adjacent fuel tank was damaged, according to the agency's directive. The agency would not identify the airlines or where the planes were located.
Slats are panels at the front of a jet's wings. They slide forward before landing to increase the wing's lift so the plane can fly slower. Three days after the accident on the Taiwanese jet, Japanese investigators found that the slat mechanism had forced a loose bolt into the adjacent wing fuel tank and punctured it, said Kazushige Daiki, chief investigator at Japan's Aircraft and Railway Accidents Investigation Commission.
Fuel spilled from the leak, pooled on the ground and ignited as passengers waited to exit.
Boeing is evaluating whether it should redesign the bolt on the slat to make it less likely to come loose, said spokesman Jim Proulx.
The FAA has required airlines to examine the bolt every 3,000 hours a jet operates until a more permanent solution can be put into place, Brown said.
Boeing has sold 2,287 of the newer 737s around the world, including 783 to airlines in the USA. Southwest Airlines, the largest operator of the jets in this country with 277, has already completed its inspections, said spokeswoman Edna Ruano. She declined to say what the airline found.
Continental, Delta, American, Alaska, AirTran and ATA also have the jets. The airlines "do not expect any impact to scheduled service," said Victoria Day, spokeswoman for the Air Transport Association.