THE bureau is serving as the research division of the aeronautics branch of the Department of Commerce.
One of the developments upon which the bureau has been engaged for about a year is the use of radio to aid airplanes landing at an airport in dense fog when the ground is invisible.
Numerous methods and devices are being tried, and two more years may be needed to reach a complete solution of the problem.
The pilot landing in fog must be given instantaneous information on his three co6rdinates in space. That is, he must be guided to and along a suitable runway, must know how far along it he has gone, and the height of the landing path above ground must be properly regulated.
Of these three requirements, the first is given by a small directive radio beacon, the second by a marker beacon, and the third by a landing beam.
The first of these, the small directive beacon, has been installed by the bureau both at its own field, College Park Md.. and at Mitchel Field, L. I., for the Guggenheim Fund.
At Mitchel Field, successful blind landings were made by Lt. J. H. Doolittle in September, using this beacon in conjunction with several non-radio instruments.
At College Park all three elements of the system have been installed, the small directive beacon, marker beacons, and the landing beam.
The first two are identical in principle with the same devices developed for use on the airways for guiding airplanes from one airport to another; these are described in the bureau's release, "Aircraft radio beacon development by the Bureau of Standards," and in Air Commerce Bulletin.