What happened
On July 11, 2021, an Airbus A220-300, registration YL-AAQ, was operating a scheduled passenger flight from Riga (EVRA) to Copenhagen, Kastrup (EKCH). During the descent into Copenhagen, the flight crew operated the aircraft under Instrument Flight Rules (IFR) with both the autopilot and autothrottle engaged. As the crew moved the thrust levers to the idle position, the autothrottle disengaged.
Following this disengagement, the 'R THROTTLE FAIL' master caution light illuminated. The crew initiated the relevant non-normal procedures outlined in the Airplane Flight Manual. As the aircraft touched down on the runway, an uncommanded dual engine shutdown occurred. Despite the loss of engine power, the crew successfully maintained control of the aircraft, vacated the runway, and brought the plane to a complete stop on a taxiway. There were no injuries and no damage to the aircraft.
The investigation
The Danish Accident Investigation Board (AIB Denmark) was notified of the event by the Transportation Safety Board of Canada (TSB) on July 13, 2021. Because Canada serves as the State of Design and State of Manufacture for the aircraft, AIB Denmark delegated the full safety investigation to the TSB. The investigation focused on the sequence of events leading from the autothrottle disengagement to the simultaneous shutdown of both engines upon ground contact.