The discovery of cracked engine-mounting pylons on two Boeing 767s in American Airlines’ fleet has prompted Boeing to ask airlines to perform more frequent inspections.
Boeing is still formulating its request, but the company said it will considerably shorten the 1,500-cycle interval between inspections of the key part that connects the engine to the 767’s wing.
American mechanics discovered a cracked pylon by chance on one of its 767 jets that had fewer than 500 cycles since its last inspection. Subsequent inspections of other 767s in American’s fleet discovered another plane with the damaged part.
A cycle is one landing and takeoff.
The pylon is a critical part because a large crack could widen under stress, and an engine could fall from a wing. An engine that fell from a wing of an American DC-10 on takeoff from Chicago’s O’Hare Airport in 1979 caused the three-engine jet to crash killing 271 passengers and crew members.
When the engine fell, it damaged critical control surfaces and hydraulic lines, making the jet uncontrollable.