The Apache is an attack helicopter used to provide air support for military personnel. It is first seen idling on a helipad in the chapter Inbound, and engaged in combat in the chapter Surface Tension.
The Apache will attack the player and any non HECU soldiers with a mounted machine gun and air-to-surface missiles. When it is defeated for the first time at the dam during Surface Tension, it will fly away. Later in the chapter when it is encountered on the cliff face, defeating it will cause it to explode.
- Note: This information is implied to be outdated and incorrect. 
Fictional scene where the Apache engage a Gargantua near point-blank range with rockets and its mounted chain gun.
- Unlike the M2 Bradley or F-16 of Half-Life, the AH-64 Apache Helicopter has not been replaced with it's Marine counterpart (which would have been the AH-1 Cobra or AH-1Z Viper). However, the black 'ARMY' decal has been removed from the aircraft.
The Apache's cockpit windshield is reflective thanks to specular reflections in the Source engine, handled by cubemaps. In order to keep the map sizes low and playable, the cubemaps are low resolution and placed in areas of high contrast close to the player. Any point entity (like props and NPCs) will reference the env_cubemap that's nearest to it at any given time.