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FAA and EASA issue Emergency Airworthiness Directive for CFM56-7B engine inspections
21 April 2018

The U.S. Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) issued Emergency Airworthiness Directives, requiring inspection of CFM56-7B engines, in the wake of the accident involving Southwest flight 1380.

On April 17, a Boeing 737-700 of Southwest Airlines, powered by CFM56-7B model engines, experienced an engine failure due to a fractured fan blade, resulting in the engine inlet cowl disintegrating. Debris penetrated the fuselage causing a loss of pressurization and prompting an emergency descent. Although the airplane landed safely, there was one passenger fatality.

The FAA AD (2018-09-51) details specific series of CFM56-7B model engines with 30,000 or more total accumulated flight cycles since new. The FAA requires that airlines within 20 days after receipt of this AD, perform a one-time ultrasonic inspection (USI) of all 24 fan blade dovetail concave and convex sides of these engines to detect cracking.

On the same day, EASA issued Emergency AD 2018-0093. This AD describes similar required actions for engines with 30,000 or more engine cycles. However, EASA also requires an inspection on engines with less than 30,000 engine cycles. These need to be checked before exceeding 20.000 fan blade cycles, or within 133 days after the effective date of this AD, whichever occurs later.
Also, the EASA AD requires inspections to be repeated at intervals not exceeding 3,000 engine cycles.

The EASA AD supersedes a previous AD (2018-0071), dated March 26, 2018. This AD was issued following a previous engine failure event and required inspections within 9 months.

CFM56-7B engines are known to be installed on, but not limited to, Boeing 737-600, 737-700, 737-800 and 737-900 aircraft.