Some more of the history of IFR navigation, from the history of College Park Airport, MD.
This includes more details of the vibrating reed instrument in Mitchells plane, and its limitations. These were the attempts that came before Mitchell's historic flight. A few observations that seem relevant to the differences are as follows:
Field elevation at Annacostia Naval Airport are at the same elevation, so takeoff and landing were at the same altimeter indication.
The short dead reckoning flight assured suitable positioning for the instrument system to be accurate. Mitchell's test also had this advantage.
The grass runway landed on was 200 feet wide 3000 feet long, and had no obstructions higher than 5 feet. Mitchell's airport was similar.
note at the end of the description, the experiments failed to get used, because the airline pilots did not trust the technology.. As Mitchell observed, they had faith in "The seat of their pants" That was a hard sell, as those that had flown in cloud and survived had faith in their special skills, those who died had no story to tell. Obviously, they were inferiors pilots.
Firsts at College park Airport
RADIO NAVIGATION AIDS
Before the world could have reliable airlines, overnight shipping, and all weather fighters, researchers and inventors had to develop a system for pilots to navigate and land their aircraft without seeing the world around them. Until a pilot could safely fly at night, in fog, or other poor weather, flight also could not compete with the railroads or trucks. From 1918-1934, the National Bureau of Standards (NBS), the U.S. Navy, the Post Office, and other government and private organizations regularly used College Park Airport to design and test "blind flight" systems. Their work is part of the foundation of the modern Instrument Landing System still used today.
National Bureau of Standards Involvement
When the Air Commerce Act of 1926 dramatically increased the federal government's role in developing and regulating aviation, National Bureau of Standards (NBS) officials became responsible to lead specific areas of aeronautical research, including developing radio aids to navigation. That summer, NBS started developing College Park as one of its field sites. They soon erected a 70-foot wooden tower supporting 2 antennas and a 500-watt radio transmitter. Early success came in 1927, when NBS tested a "vibrating reed" visual radio beacon indicator. In this system, the ground transmitter emitted 2 radio signals for the plane to receive. If the pilot was in between the 2 signals, the 2 reeds on the airplane would appear the same length.
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Pilot James Kinney and Check Pilot Clarence Young with the hooded Curtiss Fledgling aircraft used in blind flying experiments, College Park, 1933 (CPAM Photograph, Kear Collection)
When the plane was too far to the left or right to find the airfield, the corresponding reed would appear longer. However, the system was not accurate enough, did not respond fast enough to changes in direction, and was too heavy for commercial aircraft.
Blind Landing
In 1931, a brand-new Curtiss Fledgling J-1 Special, a 2-place open cockpit biplane trainer, was acquired for blind flying tests. It had a collapsible hood that could cover the pilot's cockpit for blind flying tests without obstructing the view of the backup pilot. On September 5, 1931, Marshall Boggs used this plane to complete the first blind landing at College Park, with James L. Kinney as check pilot. While accuracy was improving, the system was very sensitive and was only effective in good weather (no wind, no turbulent air, no radio static), the opposite of when instruments were needed.
Washington Institute of Technology
In late 1933, financial cutbacks dictated by the Great Depression ended the government organized development. However, several former NBS employees then established the Washington Institute of Technology (WIT) to continue developing radio navigation at College Park. WIT then produced blind flying instruments for the U.S. Navy to test. On May 1, 1934, Navy Lt. Frank Akers took off from Anacostia Naval Air Station in a Berliner-Joyce OJ-2, and successfully landed at College Park using only the WIT instruments. A little over a year later, on July 30, 1935, Akers used similar equipment to land on the aircraft carrier USS Langley, while it was underway off the coast of San Diego. Despite these successful tests, the technology was not yet accurate enough for regular aircraft carrier operations. However, it was useful for Navy seaplanes.
Although the Navy didn't purchase the system, WIT officials created the Air-Track Corporation of College Park to sell the landing equipment to commercial airports. Pittsburgh, PA, officials bought and installed the system leading to the first blind landing of a passenger-carrying flight on January 28, 1938. Unfortunately, pilots never trusted the system enough to encourage air
