Latent damage to fire-button pin triggered A321neo uncommanded engine shutdown

Investigators believe a damaged retaining pin within the overhead fire-control panel on a TAP Portugal Airbus A321neo led to an uncommanded in-flight engine shutdown, when it released a fire push-button during turbulence. Portuguese investigation authority GPIAAF says the aircraft (CS-TJL) had been cruising at 37,000ft en route from Milan to Lisbon on 23 October last year. While the captain was alone in the cockpit – the first officer having left for the lavatory – the jet encountered moderate turbulence. The aircraft subsequently alerted the captain to a shutdown of the right-hand CFM International Leap-1A engine. After the first officer returned a few seconds later, the crew declared an emergency, commenced a descent to 22,000ft and twice attempted, unsuccessfully, to relight the engine. The crew diverted to Barcelona where the jet landed safely. None of the 201 occupants was injured. As the A321neo was parking, the crew noticed that the fire push-button for the right-hand engine had popped from its normal location, and its guard was open. There had been no fire, and the button did not illuminate. But its release had triggered the automatic shutdown of the engine in flight. This resulted in arming of the extinguishers and an engine-shutdown alert message to the captain. Airbus’s and TAP’s operating procedures did not require the condition of the overhead fire-control panel to be checked after an in-flight shutdown, says the inquiry. GPIAAF found that the panel, built in 2009, had originally been installed on an A320.<br/>