Two Planes Show Problem That May Have Led To China Airlines Fire

For the second time in this week, the Federal Aviation Administration ordered airlines flying Next-Generation 737s to inspect those planes' leading edge slat tracks for evidence of a potentially serious condition.

As ANN reported earlier this week, the FAA issued an Airworthiness Directive ordering eight US carriers to inspect their newer Boeing 737 wings for loose or missing parts in response to a fire that erupted on a China Airlines jet last week. All 165 people onboard the 737 escaped before fire enveloped the aircraft, destroying it.

Carriers immediately set about inspecting their 737 fleets for signs of loose or missing parts in the slat downstop assembly, which limits how far the leading edge slats deploy during takeoff and landing operations. The slats are used to increase the wing's surface area during low-speed maneuvering.

The FAA issued a second AD Tuesday, reducing the deadline for those inspections to be completed from 24 days to 10, after two planes showed signs of the same problem thought to be the culprit behind the August 20 China Airlines incident at Okinawa's Naha Airport.

FAA spokesman Les Dorr told The Associated Press in both cases, inspections revealed parts were missing from the downstop assembly and where lying loose in the housing separating the slat assembly from the wing fuel tanks. In one of those cases, Dorr added, the housing wall was damaged from the loose parts abrading against it.

Dorr said carriers may either conduct the detailed inspections outlined in the original AD, or can rely on borescope inspections to expedite the process. Inspectors must verify all necessary parts are in place, paying particular attention to a washer used to hold the nut on the downstop assembly bolt.

As long as no damage is found, carriers may take the full 24 days to retighten the bolt assembly to specs.

The Airworthiness Directive applies to 783 US-registered 737-600, -700, -800, -900, and -900ER models. The first planes of the type -- termed the "Next Generation" 737 Family by Boeing -- flew in 1998, when the -700 entered service with Southwest Airlines.

Some 2,287 aircraft of the type are in service throughout the world... and it's likely the AD will be applied to the worldwide fleet. Many carriers around the globe -- including China Airlines -- have started inspection programs of their own.

FMI: www.faa.gov, www.boeing.com