Let George Do It

Step by painful step, pilots are learning how to land their aircraft in the foulest weather. Latest step: Hitching electronic landing systems to the automatic pilot, known to service pilots as "George."

Two electronic instrument-landing methods are already in practical use. One, ILS (InstrumentLanding System), projects into the sky a narrow beam of high-frequency radio waves. Slanting at a gentle angle, the beam forms a "glide path" which an airplane equipped with the proper instruments can follow down through the fog.

The other system, GCA (Ground-Controlled Approach), watches the approaching airplane through the fog by radar. Operators, who know exactly where the airplane is at all times, coach the pilot by voice radio and "talk him down."

Prompt Response. Both systems put a severe strain on the pilot. Besides flying his airplane and watching intently for the first sight of the ground below, he must also watch the ILS instruments or listen to the GCA talker, or do both to check one against the other. When the plane gets near the ground, both landing systems abandon it. The pilot must make the final approach and landing himself, though the visibility may still be too poor for him to see the ground properly. With the pilot's attention so completely occupied, any emergency, such as minor mechanical trouble, is more likely to develop into an accident.

Designers of landing systems hope that most of the disadvantages can be eliminated by the automatic pilot. Already the autopilot flies many airliners on long, boring hops, keeping them on course by its own gyroscopic control of the aircraft. It responds more promptly than a human pilot. Instrument men believe that it could be made to listen for electronic orders and follow them down to the ground.

George can probably do it. Experimentally at least, the automatic pilot has been hitched to both ILS and GCA. When following the ILS glide path, George accepts electronic signals from the ground and nudges the airplane's controls to keep it in the center of the beam. The pilot is free to watch the plane's flying instruments and to monitor the whole operation.

Toward the Touchdown. George can be used with GCA too. In one such system designed by Gilfillan Bros., Inc., a radar picks up the approaching airplane and automatically sends out coded orders to put it on the desired glide path. George translates the orders into the proper movements of the airplane's wheel and throttle, and steers the plane down toward the field. The system can keep track of six incoming airplanes simultaneously. If one of them has no automatic equipment, it can be talked down by voice.

Additional equipment will allow George to make the actual touchdown. One gadget, for use with ILS, is a sensitive altimeter that tells George when the airplane is close to the ground. Then George flattens the approach angle so that the touchdown will be gentle. With the GCA system, a special short-range radar does much the same thing, guiding the plane with extra precision just before it hits the runway.

Neither of these wholly automatic systems is ready for practical use, but instrument men believe that one or both of them will some day solve the blind-landing problem.

This file is automatically generated by a robot program, so reader's discretion is required.