BUCYRUS -– A Cleveland Clinic helicopter was forced to make an emergency landing after an unknown object damaged the aircraft and caused an engine fire.

The Cleveland Clinic Air Ambulance was headed to Mansfield when it detoured and landed at Port Bucyrus-Crawford County Airport on Friday evening.

There were three members of a flight crew on board at the time, along with a pilot, but no patient-passengers. No one was injured.

The impact with the unknown object happened approximately 5 miles east of the Bucyrus airport, and an engine fire alarm initiated the emergency landing.

The fire was extinguished in flight and the helicopter safely landed at the airport.

Maintainence workers began investigating the cause of the precautionary landing on Saturday.