Canadian airline Westjet on Friday cancelled a flight just prior to take-off after a warning light went off in the cockpit of the Boeing 737 MAX aircraft.
The 737 MAX had only been allowed by Canada to fly in its airspace days earlier, after Boeing addressed technical issues and improved pilot training on the MAX in the aftermath of two fatal crashes that had led to it being grounded worldwide for almost two years.
WestJet Flight 658 from Calgary to Toronto left the gate with passengers on board, but was forced to turn around, a company spokeswoman told AFP in an email.
"After a normal engine start, a standard function of the health monitoring system indicated a potential fault that needed to be verified and reset," WestJet's Lauren Stewart said.
"This process takes time and requires a subsequent engine run, which we do not perform with guests on board," she said, adding that the flight was cancelled and passengers were rebooked on another flight.
The 737 MAX aircraft was subsequently cleared by maintenance crews and has been scheduled to return to service on Sunday.
"This was to be our third commercial flight (of the 737 MAX) since the skies reopened," WestJet said in a statement.