Abstract: An airport surface collision-avoidance system (ASCAS). An exemplary system includes sensors (e.g., radar) at light modules about an aircraft, with user interface devices located with airport ground personnel and in the cockpit of the aircraft. The system helps to avoid collisions on the airport surface, i.e., during taxiing clear of airport buildings, during taxiing close to airport buildings, during gate operations (push-back and standing), etc. The system includes components for communicating sensor information to ground service equipment (tug tractor, baggage cart, refueling truck, etc.). The system can determine possible collision for any part of the aircraft (wingtip, tail assembly, engine cowl, fuselage, door, etc).