A door gunner provides firepower cover for a helicopter, disembarking or loading troops, as well as for other vehicles, ships and aircraft in the immediate vicinity. Commonly armed with a machine gun, the door gunner is able to fire many rounds in a short time in an attempt to keep the hostile forces from firing on the aircraft. One exception to the machine gun is found with U.S. Coast Guard helicopter door gunner armament. This soldier typically uses a sniper rifle, which is used to disable the engine on a fleeing watercraft. When not firing a weapon or providing cover for the helicopter, the gunner often assists the crew chief with pre-flight or post-flight inspections as well as combat observation duties.
The door gunner position became a necessity as the helicopter became more and more useful in combat situations. For many countries, this was the period of the Vietnam War. The American and Allied helicopters were fitted with a .30-caliber machine gun, known as an M-60, in the side door of the aircraft. The earliest soldiers performing door gunner duty secured the weapon on swiveling mounts to provide covering fire for soldiers getting on or off of the aircraft at a landing zone. The position offered very little cover and it was not uncommon for the door gunner to be wounded or killed in the first several seconds of any fire fight.
Many door gunners, frustrated with the lack of mobility that the swivel mounts provided the M-60, urged with ultimate success that the weapon be suspended by rubber straps. This allowed the gunners to move the machine gun in a much greater range while providing increased cover for the aircraft. During flight, the typical job of the door gunner was to survey hostile ground positions while making detailed mental maps of enemy encampments, troop movements and other pertinent battle observations. This information was generally given to commanders during a post-flight debriefing.
Other tasks carried out by the door gunner are cleaning and maintenance of the aircraft, along with assisting the crew chief with any inspections of the aircraft. The gunner is also schooled in basic first aid so that he might be able to assist any wounded soldiers who are loaded onto the aircraft. Always an infantry soldier first, the door gunner is schooled in the art of war and is capable of taking up small arms and fighting should the helicopter be shot down or otherwise become disabled.