A Defence Forces helicopter door “detached” and landed in the grounds of a secondary school in Dublin on Thursday night, the military said.
At approximately 5.52pm, the rear door of an Emergency Aeromedical Service helicopter fell away while returning to Casement Aerodrome and landed more than 250 meters below in Moyle Park College, Clondalkin.
A Defence Forces statement said: “Nobody on the ground, or in the air, was injured in the incident.
“The crew of the AW139 helicopter had successfully completed a life-saving mission to a Dublin hospital and were returning to Baldonnel for fuel.
“The area in which the door fell was secured by Defence Forces personnel and An Garda Siochana within five minutes of the incident and an investigation team were on scene within 30 minutes.
“Once the area has been analysed the door will be removed and transported to Baldonnel.”
The service will recommence on Friday, as normal, with a replacement aircraft and crew.
The statement added: “A full investigation will be conducted into the cause of this incident.”
Locals in the area claim it hit the roof of a building on the way down, saying it could clearly be heard.
It is not the first incident of its kind involving this Air Corps helicopter model - AW139.
It was the same model that lost a door while flying over Killarney golf club in 2009, with a government minister on board.
The then-tourism minister Martin Cullen was being flown back to Dublin when that incident occurred, with the door later found in Killarney National Park.