US regulators are requiring operators of more than 500 US-registered Boeing 737-300, -400 and -500 “classic” aircraft to inspect the slat assemblies on the wings for damaged, missing or incorrectly assembled hardware that could cause fuel leaks and fires when the mechanisms operate for takeoffs and landings.
The final airworthiness directive (AD) issued by the US FAA complements an AD issued in September 2007 for Boeing Next Generation (NG) 737-600, -700, -800 and -900 and -900ER models after a China Airlines 737-800 was destroyed by fire in Naha, Japan on August 20, 2007. The AD called for repetitive inspections of the slats every 3,000 cycles.
In the China Airlines accident, loose parts pierced a fuel tank when the slats were retracted after landing. Passengers safely evacuated the aircraft after the fire erupted.
According to the FAA, Boeing has cited “numerous reports of fuel leaking from the slat track housing (referred to as the ‘slat can’)” on 737 Classic aircraft. “In all cases, there were no reports of a fire as a result of fuel leaks,” the agency writes.
The new AD, which goes into effect April 8, requires operators to perform an initial inspection within 90 days and repeat inspections at intervals not to exceed 4,500 flight cycles.
According to Flight’s ACAS database, there are 562 Boeing 737 Classic aircraft actively flying in the US fleet.
Source: flightglobal.com's sister premium news site Air Transport Intelligence news