Close air support
An Apache attack helicopter provides close
air support to United States Army soldiers
patrolling the Tigris River southeast of Bagh-
dad, Iraq during the Iraq War.
In military tactics, close air support (CAS)
is defined as air action by fixed or rotary
winged aircraft against hostile targets that
are in close proximity to friendly forces, and
which requires detailed integration of each
air mission with fire and movement of these
forces.[1]
The determining factor for CAS is detailed
integration, not proximity. CAS may need to
be conducted not
in close proximity to
friendly forces, if the mission requires de-
tailed integration with the fire and movement
of these forces. A closely related subset of air
interdiction, battlefield air interdiction de-
notes interdiction against units with near-
term effects on friendly units, but which does
not require integration with friendly troop
movements. The term "battlefield air inter-
diction" is not currently used in US joint
doctrine.
Close air support requires excellent co-
ordination with ground forces. In advanced
modern militaries, this coordination is typic-
ally handled by specialists such as Joint Fires
Observers, Joint Terminal Attack Controllers,
and airborne Forward Air Controllers (FAC).
History
World War I
The use of aircraft in the close air support of
ground forces dates back to World War I, the
first significant use of aerial units in war-
fare.[2] Air warfare, and indeed aviation it-
self, was still in its infancy - and the direct ef-
fect of rifle calibre machine guns and light
bombs of World War I aircraft was very lim-
ited compared with the power of (for in-
stance) a World War II fighter bomber, but
close support aircraft still had a powerful
psychological impact. The aircraft was a vis-
ible and personal enemy - unlike artillery -
presenting a personal
threat
to enemy
troops, while providing friendly forces assur-
ance that their superiors were concerned
about their situation. Most successful attacks
of 1917 - 1918 included planning f