An Ornge air ambulance helicopter was forced to make an emergency landing in a Toronto park after a mechanical issue, which caused a door to open in flight on Friday evening.

A spokesperson with Ornge said the helicopter departed from its base in Toronto at approximately 6:15 p.m. to do a patient transport with two pilots and two paramedics on board.

The patient was not yet on the helicopter when the mechanical issue forced the emergency landing in Colonel Samuel Smith Park, which is located on the western waterfront near Humber College.

There was some structural damage to the helicopter as a result of the landing, Ornge said.

The helicopter will remain in the park until the Transportation Safety Board, which is investigating, gives Ornge permission to move it.

Ornge will also do its own investigation into the emergency landing and the mechanical issue, the spokesperson said.