The Luftwaffe was not the only service that used searchlights to aid their night defenses. The British, too, employed these over England to protect the bomber stream and guide their night fighters to intercept the German planes.
Searchlights "blind" German fighters and reduce their score by -1VP if in the same hex as the bomber on a "one for one" basis. They also guide the Mosquito towards the night fighter; the Mossie earns +1VP per German plane and searchlight combo in the same hex to a max of 2VPs.
Expands:
Duel in the Dark