The US Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) have issued emergency airworthiness directives requiring operators to inspect fan blades on older CFM56-7B engines within 20 days.
The directives apply to CFM International engines of the type that was fitted to the Southwest Airlines Boeing 737-700 that suffered an uncontained engine failure on Tuesday.
A passenger was partially sucked out of the aircraft as hull damage caused decompression. She was pulled back in by other passengers, but later died of her injuries.
Initial National Transportation Safety Board inspections of the Southwest engine showed a fan blade had detached and there was evidence of metal fatigue in the fractured blade.
Engines with over 30,000 total cycles from new must complete the inspections within 20 days, the FAA said. The CFM engines subject to the emergency directives number 681 worldwide and 352 in the US.
CFM56-7B engines with fewer than 30,000 cycles will have to be inspected within 133 days, EASA said.
If a discrepancy is detected on an affected fan blade, it must be replaced before flying again, the EASA directive states.
Another of Southwest’s 737-700s suffered a similar uncontained engine failure in 2016 on a flight to Orlando. The NTSB said a fan blade separated from the fan disk and showed evidence consistent with fatigue crack growth. The FAA issued an airworthiness directive requiring ultrasonic inspections after that event.
The CFM56 engine is manufactured by CFM International, a joint venture between GE Aviation and Safran Aircraft Engines.