To evaluate area navigation techniques in the air traffic control system, a series of test programs have been undertaken by American Airlines. Operations have been conducted in various types of jet transports during the course of regular airline service. Systems used were based mainly on VOR/DME signals, but some tests involved use of an Inertial Navigation System. Further trials are currently in progress as part of the airline's STOL evaluation project in which a number of additional systems are being examined.
