Definition of "downing"

In several recent helicopter downings, the attackers used a variety of weapons […] .

2007 February 18, Michael R. Gordon, “Planning Seen in Iraqi Attacks on U.S. Copters”, in New York Times‎

This was not just a downing of fierce rivals for the home side, it was three precious points to go towards their quest to stay in the top flight.

2013 November 3, Delme Parfitt, “Cardiff City 1 - 0 Swansea City: Steven Caulker heads Bluebirds to South Wales derby win”, in Wales Online