Two police helicopters collided in the Los Angeles area yesterday, leaving five officers and a civilian with minor injuries. Investigators believe the crash occurred when the rotator blades touched of a chopper that was landing and one that was taking off. The collision caused extensive damage to both aircraft, crumpling the tail and breaking the blades of one and causing the blade to fall off and other damages to the other. The injured included a pilot and an observer in each of the Bell OH-58A helicopters and two officers on the ground. The FAA and the National Transportation Safety Board were investigating.