WASHINGTON — American Airlines failed to catch mistakes by maintenance workers who didn’t follow procedure before a September 2007 flight, causing the airplane’s left engine to catch on fire during a departure climb from Lambert-St. Louis International Airport, safety investigators concluded on Tuesday.
The findings by National Transportation Safety Board investigators come as the airline faces heightened scrutiny by the Federal Aviation Administration.
The agency recently assigned a special team of 17 inspectors to examine American’s aircraft maintenance and other operations. The special audit is expected to take about three months.
On Tuesday, the NTSB conducted a hearing to investigate American Flight 1400 on Sept. 28, 2007, when an MD-82 engine caught on fire.
The airliner returned to the airport, but the plane’s nose landing gear failed to extend during a landing attempt. A second landing attempt was successful. None of the 143 people onboard was injured, but the plane sustained substantial damage.
Investigators said the aircraft’s left engine had repeated trouble starting beginning 10 days before the incident. Maintenance crews replaced a start valve in the engine six times during that period. On the day of the incident, the left engine again failed to start and had to be started manually by maintenance workers before Flight 1400 took off.
It turned out that mechanics failed to properly maintain a metal air filter that disintegrated, investigators said. The destruction of the filter led to a series of other mechanical problems, including a bent pin, which led to the valves being replaced and helped caused the engine fire.
American’s maintenance oversight system failed to catch these repeated problem, investigators said.
When the fire occurred after takeoff, the flight crew also didn’t follow emergency checklist procedures, investigators said. The co-pilot was engaged in trying to wrestle the cockpit door closed after the fire partially shutdown the aircraft’s electrical system, which released the automatic door lock, they said.
“It seems to me it was a series of people taking short cuts that accumulated on this particular day into what could have been much more catastrophic,” said safety board member Kitty Higgins.
Last month an American Airlines jet made an emergency landing at John F. Kennedy International Airport in New York following an engine failure shortly after takeoff from nearby LaGuardia Airport. Pieces of one of the jet’s two engines were found embedded in the fuselage, and other metal debris landed on the roof of a plumbing business.
Last August, FAA said it would fine American $7.1 million for continuing to fly airliners after safety problems were reported and for drug-testing violations. FAA said the Texas-based airline delayed repairs on two MD-80s — a mid-sized airliner — after problems were reported with their autopilot systems and flew them 58 times in violations of federal regulations. The airline is negotiating the fine with the agency.