According to a recent report, and a flight instructor landed safely after a mid-air collision with a police-operated drone that flew into their flight path.

On August 10, a Cessna 172 operated by Canadian Flyers International turned onto final approach for Toronto Buttonville Municipal Airport in Ontario, Canada. The student and the instructor onboard had the aircraft set up for landing and were in a stable approach when, as noted by the recent Civil Aviation Daily Occurrence Reporting System (CADORS) , the two felt a jolt that pushed them back in their seats. The pilots thought that they perhaps hit a bird and were able to continue their landing without issue.

Upon landing, the pilots noticed a large dent to their aircraft and hours later, a detective from York Regional Police confirmed that the pilots hadn’t hit a bird, but their drone.

Twitter user Ken Townsend .

The pilots say that the collision happened one nautical mile away from the airport at an altitude of about 500 feet above ground level. According to Transport Canada, drones cannot fly or without having special authorization. Drone operators within controlled airspace must also be in contact with air traffic control.

Toronto Buttonville is a controlled airport and a report from CityNews that air traffic control was not aware of any drone activity on that day. The drone was not authorized to fly in the airspace. The only statement from police is that the drone was a part of an area police operation. The owner of the flight school believes that had the drone hit higher, the pilots could have been injured or worse.

Unfortunately, the damage to the Cessna may go beyond the engine cowling. The CADORS report notes that the aircraft suffered a propeller strike in the collision and a bent airbox. An engine teardown will be necessary to inspect for any additional damage.

Hitting a drone is a pretty big deal for an aircraft, even for commercial airliners. On Sunday, an Embraer E175 narrow-body airliner departing out of Chicago O’Hare struck a drone, necessitating a return to the airport, Flight Global .

A University of Dayton Research Institute test flying at 238 mph.

The researchers found that the drone went deeper into the aircraft’s structure than a bird would, causing more damage. A Cessna 172 like the one in this incident lands at a far slower speed of around 70 mph, but a drone is still capable of causing some substantial damage.

Canadian authorities are investigating the incident as an unauthorized entry into controlled airspace.