CHARLOTTE, N.C. -- Inadequate maintenance work by a third-party contractor in Miami may have led to the collapse of the landing gear on a Boeing 757 operated by US Airways ( LCC), a Federal Aviation Administration investigation indicates. On Oct. 28, 2007, as roughly 20,000 pounds of jet fuel was loaded onto Tampa-bound Flight 1753, the left landing gear collapsed under the weight of the fuel. The plane was parked at a gate at Charlotte/Douglas International Airport, waiting to depart with 195 passengers aboard. No one was injured, but the incident raised serious questions. Had the gear collapsed under weight at a different time, such as when the aircraft was landing, the outcome might have been far worse. "We were one landing away from a disaster," says John Goglia, a maintenance safety consultant who is a former member of the National Transportation Safety Board and a former US Airways mechanic. The FAA, the NTSB and US Airways all investigated the incident. Immediately afterwards, US Airways inspected the landing gear on five other 757s that had gear work performed by the same vendor. "We replaced some of the truck beams based on the indicators we were using," says US Airways spokesman Phil Gee. The truck beam is the main component of the landing gear. Installed as if it were an upside-down T, the truck beam consists of a horizontal bar that connects the front and rear axles. The vertical bar acts as a shock absorber. The FAA's notice refers to an enamel paint applied to the inside, or "bore," of the horizontal bar. Last week, in a notice to airlines, maintenance shops and others, the FAA warned that Miami-based AAR Landing Gear Services had improperly maintained the truck beam on the main landing gear in about 350 cases between Jan. 1, 2001, and Nov. 26, 2007. The gear is used on the Boeing 707, 747, 757 and 767, but it was unclear how many had been installed.
In any case, AAR says, its maintenance did not cause the US Airways incident. "It is our understanding that the NTSB believes the cause of the US Air incident that apparently gave rise to this notice was stress corrosion unrelated to paint on the landing gear truck beam," the company said. A person familiar with the procedure questioned that explanation. Within the horizontal bar of the truck beam is a drain hole, which allows water to leak out. When AAR applied the enamel coating, "they put the coating in so heavily that it blocked the drain hole," said the person, who asked that his name not be used. Blocking the drain would allow moisture to build, which would lead to corrosion, which could cause the gear to collapse, the person said. AAR said, however, that "the paint that is applied to the internal bore of the truck beam does not even extend to the area where the drain hole is located." Meanwhile, Goglia said the Boeing ruling does not excuse the company. "They failed to follow published procedures to repair the part, so it was not legal to install the part on an airplane," he said. "If they get approval to do alternate means, that's fine, but they are supposed to get it before they do the work." As the broader market climbed Tuesday, shares of Boeing and US Airways also rose, 1.5% and 8%, respectively.