Blind

The Army, the Navy and experimenters for air transport lines have made thousands of blind landings. But last week Pennsylvania-Central Airlines--which has operated over the Allegheny Mountains between Washington and Cleveland for eight years without a fatality--set a ship full of passengers down on Pittsburgh's all-paved airport solely by instruments--and thus claimed to have made the first commercial blind landing. There are Army, Navy and airline blind landing systems. The one used in this case is called "Air-Track," a radio-guided approach system designed to standardize and safeguard all landings, but still awaiting Bureau of Air Commerce approval for all weathers.

Air-Track, delayed by the Depression, has been ten years perfecting under Dr. Frank G. Kear and Gomer L. Davies of Washington Institute of Technology, Harry Diamond of the National Bureau of Standards, and the Bureau of Air Commerce radio development chief, W. E. Jackson. It consists of three radio transmitters, one to send a radio course beam, one to send a glide beam, and a radio marker beacon. Beacon, transmitters are housed in an automobile trailer that can be moved to the various runways on the landing field. The marker beacon is installed at the end of the runway (see cut).

In practice the pilot approaches the airport in the normal manner along the regular route beam. Twenty miles out his radio receiver, containing a reed converter, locates the course beam from the transmitter-trailer. About four miles from port at a given altitude it strikes the glide beam, a curved path of constant intensity in a field of radio waves. On the pilot's dashboard is a "cross pointer dial" operated by the reed converter. One needle indicates the course beam, the other the glide beam. Keeping the needles crossed at right angles,* the pilot guides his ship down the beams. As he passes the boundary of the airport at a known altitude the marker beacon signals his position. Whatever the weather, the pilot, eyes only on his instruments, theoretically lands his ship surely and safely on the runway.

* If he is off the course the vertical needle on the dial will waver to one side. If he is off the glide beam, the horizontal needle rises or falls.

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