US regulators plan to require airlines to inspect some 2,200 Boeing 737s and 757s due to a risk that improper maintenance could have jeopardised the integrity of the jets’ main landing gears.
The Federal Aviation Administration (FAA) on 7 July issued a proposed rule addressing the concern, which became evident following the collapse of a 767’s main landing gear.
The 767 incident occurred after workers improperly used a grinder to “machine the inner diameter” of the jet’s main landing gear outer cylinders, causing heat damage, the FAA says.
The agency in February issued an airworthiness directive addressing the issue in 767s.
Now, the FAA says 737s and 757s may also be affected. It notes that workers at the same maintenance site used the same grinder on main landing gear cylinders of 166 Boeing 737s and of 20 757s.
“This condition… could cause failure of a principal structural element to sustain its limit load, which could result in loss of control of the airplane,” the FAA says.
It adds that “heat damage” could cause the gear to fail, perhaps in a manner that punctures the jets’ fuel tanks.
Boeing sought to address the concern with 737- and 757-specific Alert Requirements Bulletins issued in January. Those bulletins call on airlines to inspect 1,833 737s and 399 757s to determine if the jets have affected main gear outer cylinders, and to replace affected components.
The FAA’s proposed airworthiness directive would mandate that work.
