TSB releases investigation report into 2022 runway overrun of Boeing 737 in Kitchener, Ontario

The Transportation Safety Board of Canada (TSB) has released its investigation report (A22O0161) on the 2022 runway overrun of a Flair Airlines Boeing 737-800 at the Region of Waterloo International Airport in Ontario. There were no injuries.

On November 25, 2022, the aircraft departed from Vancouver, British Columbia, with an inoperative left engine thrust reverser. There were six crew and 134 passengers on board. During the landing approach, the captain left the engine autothrottle engaged after disengaging the autopilot. Shortly before landing, the captain intended to disengage the autothrottle, but inadvertently pressed the takeoff/go-around (TO/GA) switch. This caused the autothrottle to command an increase in engine thrust. The TO/GA cockpit indications went unnoticed, as the flight crew's primary focus was outside the flight deck.

The captain held both thrust levers at idle during the landing flare. After touchdown, the captain removed his hand from the left thrust lever to activate the right engine thrust reverser. With the aircraft still in go-around mode, the right engine was producing reverse thrust and the left engine began advancing towards maximum thrust, deactivating the automatic systems that help stop the aircraft and causing control difficulties. The captain managed to stay on the runway and used manual braking to slow down; however, there was insufficient runway remaining on which to stop, and the aircraft overran the runway by approximately 500 feet.

The investigation found that there were several factors which contributed to the inadvertent press of the TO/GA switch and the undetected flight mode change. These include pilot fatigue, the attention of both pilots focused outside the aircraft during the flare and landing, and that the aircraft systems did not provide visual and aural cues that were noticeable enough by the flight crew to indicate the inadvertent mode change during that phase of flight.

A defect with the aircraft's left thrust reverser was first reported in May 2022, over six months before the occurrence, and 22 subsequent reports provided an opportunity to troubleshoot the problem. Despite this, the defect did not meet the regulatory definition of a recurring defect, thus, Flair's maintenance control software did not identify it as such. If the underlying issue behind a persistent maintenance defect is not addressed in a timely manner, there is a risk that it may compound, resulting in a serious consequence.

Following the occurrence, Flair Airlines modified its operating procedures to better support the existing requirement to disengage both the autopilot and autothrottle at the same time.

See the investigation page for more information.