Incident Overview
Two pilots had planned local sightseeing night flights in separate Cessna 172 aircraft. Both airplanes were flying on an easterly heading, with N78239 (a C172K) ahead of N73L (a C172D). The pilots maintained radio contact with each other, and air traffic control was not involved.
Maneuvers and Collision
N78239 initiated a 360-degree turn and, after resuming an easterly heading, visually acquired the lights of N73L. The pilot of N78239 reported that 'suddenly we hit,' despite believing at the time that the spacing between the aircraft was approximately 2 miles.
Post-Impact Events
N78239 landed without further incident, although it experienced flight control problems. N73L lost directional control upon landing and subsequently collided with a parked airplane.
Damage Assessment
Inspection of both aircraft revealed that N78239 struck N73L from the rear. The right wing leading edge of N78239 contacted the left main landing gear of N73L. The impact broke the wing spar of N78239 and separated the left main gear from N73L.