The copter suffered engine failure but managed to make its way to to the airport and land safely with injury to pilot or crew.
Detective Superintendent Richard Campbell, from the PSNI’s Air Support Unit, said: “An aircraft from the Air Support Unit made an emergency landing last night (Thursday 12th) at The City of Derry Airport.
“This came after experiencing engine failure while supporting District Policing colleagues who were dealing with a security alert in Limavady, which was later declared an elaborate hoax.
“The pilot and crew landed the plane safely without damage being caused and no injuries were sustained by those on
board.
“The matter has now been referred to the Civil Aviation Authority and the Air Accidents Investigation Branch.
“We are fully co-operating with them as they work to establish the circumstances surrounding the engine failure.”