WestJet flight bound for Toronto was grounded at YYC Calgary International Airport Friday after pilots were warned of a “potential fault” in the Boeing 737 MAX aircraft.According to WestJet, Flight WS658 had passengers on board and was getting ready to take off, when it was “returned to the gate after push back.” WestJet returning Boeing’s troubled 737 MAX 8 to service with commercial flight “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 spokesperson Lauren Stewart said in an emailed statement.“This process takes time and requires a subsequent engine run, which we do not perform with guests on board.”Stewart said the flight was.