An Airborne Early Warning (AEW) system is a radar system
carried by an aircraft which is designed to detect other aircraft. Used
at a high altitude, the radars allow the operators to distinguish between
friendly and hostile aircraft hundreds of miles away.
AEW aircraft are used for defensive and offensive air operations. The
system is used offensively to direct fighters to their target locations, and
defensively to counter attacks.
Many countries have their own AEW systems, although the Boeing E-3 Sentry
and Northrop Grumman E-2 Hawkeye are the popular systems worldwide. The
Sentry is built by the Boeing Defense and Space Group (now
Integrated Defense Systems) and is widely considered to be an
international benchmark for AEW systems. It is based on the Boeing 707
aircraft. The E-2 Hawkeye, which entered service in 1965, is arguably the most
widely used AEW system. The E-3 Sentry is not strictly an AEW system, as it
has far more functionality. See Airborne Warning and Control System.
The United Kingdom also devolped its own AEW aircraft in the form of the
Nimrod AEW Mk.3 developed by De Havilland. Unfortunately the Mk.3 programme
was cancelled just as the prototype completed its final trails in favour of
procuring alternative existing models from the US.
The RAAF are deploying Boeing 737-based aircraft under Project Wedgetail.
Unlike the E-2 and E-3, Wedgetail does not have a rotodome. It will probably
be marketed towards many existing E-2 customers, who have no choice but to
purchase a system intended for an aircraft carrier, due to lack of options.
The Swedish Air Force use the S 100B Argus as their AEW platform. The S
100B Argus is based on the Saab 340 with an Ericsson Erieye PS-890