What happened
On April 8, 2022, an Airbus A320-214, registration CS-TNV, was involved in a serious incident during an aborted landing at Copenhagen/Kastrup Airport (EKCH). While attempting to land, the flight crew initiated a go-around after the aircraft had already engaged the thrust reversers. During this transition, the number one engine's thrust reverser failed to stow, remaining in the deployed position while the aircraft attempted to climb.
The investigation
The Danish Accident Investigation Board conducted a technical examination of the aircraft's hardware and software. Investigators performed detailed inspections of the engine #1 thrust reverser components, including the Hydraulic Control Unit, actuators, and the Engine Control Unit (ECU) memory. The investigation also included a review of the aircraft manufacturer's design and an analysis of flight data from millions of previous flights to determine the prevalence of similar scenarios.
Findings
- The primary cause of the incident was a software logic error within the CFM5 and ECU software that prevented the thrust reverser from stowing following the selection of reverse thrust during an aborted landing.
- The investigation found that the specific operational procedure—which dictates that once thrust reversers are selected, a full stop landing must be performed—was not always strictly followed by flight crews.
- Analysis of flight database records revealed that aborted landings after thrust reverser selection were more frequent than previously estimated, occurring approximately once per month across the A320 family.