The Norden thus calculated two angles: the range angle based on the altitude, airspeed and ballistics; and the current angle to the target, based on the ground speed and heading of the aircraft. The difference between these two angles represented the "correction" that needed to be applied to bring the aircraft over the proper drop point. If the aircraft was properly aligned with the target on the bomb run, the difference between the range and target angles would be continually reduced, eventually to zero (within the accuracy of the mechanisms). At this moment the Norden automatically dropped the bombs.