OTTAWA – A Canadian North passenger jet has been grounded in Ottawa for mechanical inspection after a sensor indicated a fire on board just as the plane was making its way to the runway.

The 76 people on the scheduled morning flight to Iqaluit were evacuated Monday shortly after an alarm sounded in the cockpit, the airline said.

“The aircraft received a fire warning indication in what’s called the auxiliary power unit,” said airline spokesman Graeme Burns.

That unit is in the tail section of the Boeing 737 and is used to start the engines. It also provides electricity and air conditioning for the plane while it’s on the ground.

“The pilots immediately stopped the aircraft on the tarmac while it was taxiing and followed all the procedures … to get the people off the plane,” Burns said.

The alarm turned out to be false, he added. “We are very thankful that there was no actual fire.”

There were reports of a burning odour on the plane when the sensor alarm sounded, but no visible signs of smoke and no injuries during the evacuation.

Once the evacuation order was given, the 72 passengers and four crew members disembarked the plane and were returned to the Ottawa airport lounge by bus. A short time later the Transportation Safety Board gave the all-clear for the plane to return to the terminal.

None of the passengers were able to secure alternate transportation, said Burns, so those who needed it were offered accommodations for Monday night in Ottawa.

The airline said it would have another plane available to take the passengers to Iqaluit on Tuesday.