Sentinel in the Sky

Modern radar for passenger aircraft. Shows how man has always reached for vision of the things beyond his sight, beginning, perhaps, with the ancient sailor who first climbed the mast to see over the horizon. In modern times the quest has led to such airborne aids as the gyro compass, horizon indicator and radio direction finding navigational systems. Sequences on radar show its basics and how it works in modern planes. Director: Marvin Dreyer.