We had a shoot-out involving a helicopter in Alaska about 33 years ago -- almost to the day.

A drifter from Chicago ended up murdering ~9 people (probably more) including a family of three (including the two-year old son plus the pregnant mother) near Manley Hot Springs, Alaska and eventually the state SERT team assembled a couple of helicopters to investigate a reported sighting after tracking him for a while.

Their game plan immediately went to shit when a different near-by possible sighting led to the helicopters splitting up, leaving one helicopter and three troopers to investigate the first report.

As the helicopter started descending so the troopers could get off to look around, the killer Michael Silka stepped out from behind a tree a relatively short distance away. The helicopter was about twenty feet off the ground at that point.

The troopers saw him in time to react before he got off a shot, and both sides opened fire at about the same time. Both sides missed the first barrage, with Silka's 30.06 round missing both troopers sitting in the door and punching out through the metal above their heads.

The second barrage ended with Silka hit ~eight times and DOA, while Trooper Troy Duncan was killed instantly by a round to the head/neck. The bullet fragmented after hitting Trp. Duncan and actually injured the pilot up front as well.

The entire gun-fight lasted ~two seconds.

http://www.odmp.org/officer/4362-trooper-troy-lynn-duncan

http://www.tactical-life.com/military-and-police/firefight-at-manley/

https://youtu.be/KnyWVdTTWws?t=30m58s for a History Channel special "re-enactment" featuring the other Trooper Jeff Hall, who actually fired the shots that killed Silka.