In-flight explosion creates pressure for engine inspections

Alexandra Villarreal | David Koenig
Philadelphia, US.- The engine explosion aboard a Southwest Airlines jetliner puts new pressure on airlines and regulators to act faster to inspect the fan blades that may have snapped off and triggered the accident that killed a passenger.

The initial findings from investigators show that Tuesday’s emergency was eerily similar to an engine failure on another Southwest plane in 2016. That breakdown led the engine manufacturer to recommend new inspections of fan blades on many Boeing 737s.

Investigators say a fan blade snapped off as Southwest Flight 1380 cruised at 500 mph high above Pennsylvania. The failure set off a catastrophic chain of events that killed a woman and broke a string of eight straight years without a fatal accident involving a U.S. airliner.

“This fan blade was broken right at the hub, and our preliminary examination of this was there is evidence of metal fatigue where the blade separated,” NTSB Chairman Robert Sumwalt said.

Metal fatigue — microscopic cracks that can splinter open under the kind of stress placed on jetliners and their engines — was blamed for an engine failure on a Southwest plane in Florida in 2016. Both that plane and the jet that made a harrowing emergency landing Tuesday in Philadelphia were powered by CFM56 engines.

Manufacturer CFM International, a joint venture of General Electric Co. and France’s Safran SA, recommended last June that airlines using certain CFM56 engines conduct ultrasonic inspections to look for cracks.

Last month, European regulators required airlines flying in Europe to conduct the inspections that were recommended by CFM. In the U.S., the Federal Aviation Administration proposed a similar directive last August but has not yet required the inspections.

The FAA proposal would have given airlines six months to inspect the fan blades on engines that had flown more than 7,500 flights, and 18 months on more lightly used engines. It is unclear whether that would have forced Southwest to quickly inspect the engine that blew up. CEO Gary Kelly said it had logged only 10,000 cycles since being overhauled.