FAA Issues Emergency AD for inspections of 737s
FAA Emergency AD No 2020-16-51 Dated 23 July 2020
This emergency AD was prompted by four recent reports of single-engine shutdowns due to engine bleed air 5th stage check valves being stuck open. Corrosion of the engine bleed air 5th stage check valve internal parts during airplane storage may cause the valve to stick in the open position. If this valve opens normally at takeoff power, it may become stuck in the open position during flight and fail to close when power is reduced at top of descent, resulting in an unrecoverable compressor stall and the inability to restart the engine. Corrosion of these valves on both engines could result in a dual-engine power loss without the ability to restart. This condition, if not addressed, could result in compressor stalls and dual-engine power loss without the ability to restart, which could result in a forced off-airport landing.
This AD requires inspections of the engine bleed air 5th stage check valve on each engine and replacement of the engine bleed air 5th stage check valve if any inspection is not passed.