 Once the presence of a "live" IR missile is indicated, flares are released by the aircraft in an attempt to decoy the missile; some systems are automatic, while others require manual jettisoning of the flares.The aircraft would then pull away at a sharp angle from the flare (and the terminal trajectory of the missile) and reduce engine power in attempt to cool the thermal signature.Optimally, the missile's seeker head is then confused by this change in temperature and flurry of new signatures, and therefore follows the flare(s) rather than the aircraft.