Peacetime Job

Radar applied last week for its first practical job on regular commercial airplanes. The "airline radar" developed by Electronician Dave Evans of the Hughes Aircraft Co. aims to accomplish only one thing: "terrain avoidance" (keeping the plane from hitting a hill). Many an airplane passenger, fidgeting in the overcast and wondering where the nearest "terrain" is lurking, will feel that this new gadget is worth the 15 Ibs. of dead weight and $400 installed cost.

The Hughes radar, like all others, sends out brief bursts of high-frequency radio waves both ahead of the plane and below it. When these echo back from the ground (or from the sea or buildings), a receiving apparatus measures the time the waves take to make the round trip. If any return quickly enough to indicate that an obstacle is within 2,000 ft. from the airplane, a bell rings and a bright light flashes in the cockpit. The pilot can then pull into a climb in time to avoid any "terrain" hidden in the overcast (see diagram).

The new radar might not work if the airplane were flying directly toward a vertical cliff well over 2.000 ft. high with no foothills. But according to Hughes the U.S. has no such cliffs that an airplane can smash into. The foothills or lower slopes of most mountains should give warning in ample time to avoid a crash.

To show what his gadget can do, President Howard Hughes of Hughes Aircraft loaded a Lockheed Constellation last week with newsmen and headed out over the Pacific near Los Angeles. He flew west until he was opposite the steep mountains beyond Santa Monica, which have reached for many an airplane through California fog. Turning inland, Hughes flew the plane directly toward the highest peak. The bell rang and the light flashed as soon as the radar "cat's whiskers" brushed the rising ground.

At this point there was plenty of time to avoid the mountains by an easy, gentle climb. But to show the wide margin of safety, Hughes flew the great plane into a steep-sided valley with mountains all around. At last he remarked calmly: "Now we'll take evasive action." The ship roared up in a steep, climbing turn to clear the rocks.

The new radar is being installed in the planes of Trans World Airline (Howard Hughes, chief stockholder), but Hughes promises to make it available to all airlines at cost. Though it can be set to give a special warning at 500 ft. (useful in approaching a fogbound airport or coming down through a low ceiling), it is not intended as a complete blind-landing device. Its chief usefulness is for flying between airports: if developed a year ago, it might have prevented several disasters when airplanes in thick weather hit unexpected "terrain."

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