http://www.google.com/custom?q=IHAD...esearch=fas.org

For suppression, self-protection and engagement of lightly armored vehicles and personnel, the AH-64A also carries a 30-mm lightweight machine gun. The gun can be aimed through a completely new system, the integrated helmet and display sight system (IHADSS), which establishes crew member line of sight for 30-mm engagements. IHADSS tracks the movements of the pilot's head. Literally, he simply looks, then fires.

For area target engagement, the AH-64A can also fire the standard 2.75-inch folding fin aerial rockets with a combination of warheads. This is the same rocket that has been used for years on the Cobra attack helicopter.

The two subsystems that make the AH-64A a remarkable night fighter are the target acquisition designation sight (TADS) and the pilot night-vision sensor (PNVS). The TADS is used by the gunner to engage with the Hellfire missile and, when necessary, to fly the aircraft. It contains a television system, forward-looking infrared system (FLIR), a combined laser range finder target designator, laser tracker, automatic target tracker and direct-view optics. TADS gives the gunner the capability to see and fire in daylight and darkness, through haze, smoke or fog.

The PNVS contains a FLIR that is independent of the TADS turret. It is used by the pilot to fly the aircraft at night and during other periods of poor visibility and to fire if necessary. It is slaved to the IHADSS and produces a field of view that matches the direction in which the pilot is looking. The PNVS gives the AH-64A an in-route flight capability that matches the operational characteristics of the aircraft.