How a flare can pull a missile off course
Many heat-seeking missiles use an infrared seeker: a sensor that looks for heat patterns and steers toward a likely engine source. A helicopter’s engines and exhaust can stand out against cooler surroundings, giving the seeker a target to follow.
A flare is designed to create another, intense heat source. Dropped near the aircraft, it can draw the seeker’s attention away from the helicopter. The missile may then steer toward the flare instead—especially if the flare’s heat pattern and timing make it appear to be the better target.
A distraction, not a shield
The flare has to do more than burn brightly. It must separate from the helicopter enough for the seeker to distinguish it, and it must be released at a useful moment. Aircraft warning systems can help crews detect a threat and cue countermeasures, though the precise equipment and procedures vary by aircraft.
Flares are expendable, and their effect is not guaranteed. A missile with a more capable seeker may be less easily fooled, so flares are one part of a broader defensive approach rather than a way to make the aircraft invulnerable.
The essential trick is to change what the missile sees at a crucial moment: instead of tracking one hot aircraft, its sensor is confronted with another source of heat that may look more convincing.
