After it's invention by Dr. Luis W. Alvarez, the Ground Controlled Approach (GCA) system of bringing airplanes into low approaches to airports and eventual safe landings was proven during the war by the military services.
GCA is a radar unit which enables operators on the ground to tell the crew of an airplane by radio exactly where they are and how to make a landing under practically zero-zero conditions. The ground crew knows at every moment the altitude and course bearing of the plane through radar beam blips on their scopes.
In the 15 months preceding last January, the Army Air Forces Airways Communications System claimed 2,847 routine operational landings with GCA in "impossible" weather conditions, weather in which the commercial airlines were grounded. The Navy—in particular the Naval Air Transport Service—reported 469 GCA landings for a previous 18 month period Fifty-four of these were in the foggy San Francisco Bay district last December.
The AAF Air Safety Board and the Navy report a total of nearly 20,000 additional practice landings with GCA, during which there were only two accidents. One was at Ft. Dix, where a pilot during a training flight ignored a warning that he was too low and brushed the trees. He and his crew escaped uninjured. The other was in California recently. A Navy Wave was killed [twenty other passengers escaped injury] when the plane crashed 150 feet short of the runway. Cause of the accident was 100 percent pilot error.
One amazing fact to show reliability of flight schedules when GCA units are in existence is that of the NATS “Hotshot” fun between the San Francisco area and Washington, DC. It is a two-plane-per day schedule, one leaving San Francisco at 5 pm and the other departing Washington at a pin the same day.
During the past year there was only once cancellation of the "Hotshot" in 365 days or 730 flights! Between June 20, 1946 and January 25, 1947, NATS completed 437 out of a possible 440 scheduled operations. No commercial airline operating over the same period can claim anything approaching such a record.
In the NATS eastbound flights from the Orient, especially on the 2,400 mile run between Honolulu and San Francisco, there as yet has not been one single cancellation at Honolulu because of weather conditions at the mainland’s Bay District. NATS records point this out in glaring challenge to opponents of the GCA system.
At Guam, Shanghai Tsingtao, Tientsin, and Tokyo, NATS has a record of almost 99 percent of completed flight schedules through the aid of GCA landings. In the Alaskan and Aleutian districts, where the worst possible weather prevails, the percentage was slightly lower, although the exact figures were not immediately available.
AACS (Airways and Air Communications Service) operates GCA for the AAF. During the past 15 months 2,847 operational landings have been made in weather conditions where landings without GCA would have been impossible.
The ATC is the main user of GCA. The first GCA base was installed in July, 1944, in the European Theater of Operations. They spread fast, especially in the Pacific area.
Iwo Jima was extremely important. Crippled B-29s struggled back home from bombing Japan and landed there. The Iwo Jima base claims to have saved more than 5,000 crew members.
On October 7, 1946, the night lights failed at the Iwo field A plane was picked up within 15 miles. Fortunately the GCA equipment has its own power and directed the plane until the pilot was told to turn on his landing lights. He found the runway was right in front of him.
Only a few weeks ago a C-54 was brought into an Alaskan field by GCA in a blowing snow and extreme win. Sixteen passengers were aboard. GCA is popular in Alaska due to the weather conditions there.
The spectacular accomplishments of GCA are numerous. Last October a C-54 was saved at Newfoundland on the fringe of a hurricane and in an extremely heavy rain The wind velocity was 60 to 65 miles an hour at the time of the landing. On another occasion in the same month, three planes (a C-47, C-54, and C-46) were brought in at Haneda, Japan, under a 100 foot ceiling. Only one of the three planes spotted the runway before its wheels touched.
Last January 16, when eastern seaboard airports were socked-in with bad weather and commercial schedules were seriously interrupted, three GCA landings were made at Mitchell Field when the ceiling was 200 feet and visibility only 1/16 of a mile. A Peruvian airliner was the first in, followed by a private Beechcraft, and then an Army C-54. At the same time an Army "All Weather" C-54 was brought down safely on the Andrews Filed runway under even lower visibility.
It is fairly generally known by now how during last December and early January units at Floyd Bennett, Andrews, and Patuxent River, Md., fields safely brought in more than 30 military planes when sleet, snow, and fog caused the cancellation of nearly 1,300 flights of commercial airplanes at the La Guardia Field alone. The Patuxent River Naval Air Station has not been closed down for a single day because of weather, since its GCA was installed.
While commercial carriers were running out of fuel and crash-landing on beaches, going miles out of their way to land at alternate airports when their original destinations were closed in--or when hundreds of flights were cancelled because of weather--the AAF, NATS, foreign, domestic lines and several private airplanes were being safely landed in the same vicinities and under the same severe socked-in conditions by means of GCA.
Note: The rest of the article continues with flight evaluations comparing ILS and GCA.