Air Canada says it is investigating after a passenger on board a flight from Toronto to Dubai opened a cabin door before takeoff and fell to the tarmac at Pearson Airport, sustaining injuries.

In a statement sent to CP24, Air Canada said the incident occurred on Flight AC056 on Monday while the aircraft was at the gate.

According to the airline, a passenger who had boarded the plane normally did not proceed to their seat but instead opened a cabin door on the opposite side of the aircraft.

Air Canada said the passenger was injured after falling to the tarmac.

Emergency services and police attended the scene.

The flight, which was scheduled to carry 319 customers, was delayed but departed at a later time.

“We can confirm all of our approved boarding and cabin operating procedures were followed,” Air Canada said.

It is not clear what prompted the passenger to open the cabin door.

Air Canada said it is continuing to “review the incident.”