Directional Infrared Counter Measures

Directional Infrared Counter Measures (DIRCM) is a system produced by Northrop Grumman and BAE Systems to protect aircraft from infrared homing ("heat seeking") man-portable missiles. It is a lightweight, compact system designed to provide mission vulnerable aircraft with increased protection from common battlefield threats. It is more advanced than conventional infrared countermeasures.

The term DIRCM is used as a generic term to describe any infrared counter measure system that tracks and directs energy toward the threat.

Method of operation
The system uses an active method of jamming of infrared missile seekers through the sensor aperture. The system can be placed in either active or standby mode. In the standby mode the aircrew to may select the active mode to begin jamming IR threats.

The pulsing flashes of IR energy confuse the missile guidance system.

AAQ-24 Nemesis
The AAQ-24 system is a directed infrared countermeasure (DIRCM) system. It consists of a missile warning system (AAR-54), an integration unit, a processor, and laser turrets (Small Laser Targeting Assembly, SLTA). Early versions used an arc lamp to generate the jamming signal. Newer versions produced by NGC use diode based pump systems are known by the GUARDIAN name, and will likely be fitted to many commercial carriers in the near future pending the completion of many tests on the viablility of such options.

It will be installed on C-17, MC-130, and CV-22.

LAIRCM was a requirement for protecting Large Aircraft from infrared guided missiles. The solution for this requirement is the ALQ-24 Nemesis system. Also, LAIRCM-Lite is a C-17 program that uses a combination of laser jammers and flares due to the limited availability of LAIRM components.