A Royal Canadian Air Force search-and-rescue helicopter crashed Thursday at the base in Gander, Newfoundland.
In a tweet, the RCAF confirmed the crash involved a CH-149 Cormorant helicopter.
First responders have been called to the scene but the cause of the crash is not yet clear.
The air force said six people were on board when the helicopter was doing “hovering maneuvers” prior to the crash.
Two are now in hospital. Four have been released and are with their squadron.
The Royal Canadian Air Force said its Directorate of Flight Safety is now investigating.
The Gander Airport said the accident occurred at roughly 3:40 p.m. local time, involving a helicopter that had been training on the runways. The airport is now closed to operations, it said.
An update is expected at 10 a.m. local time on Friday.