Instrument of the Week Nav Aids

The first aviation navigation aids were the beacon light towers.

By:       Norm Goyer

We all read, almost daily, about our pilotless drones knocking off high-level terrorists. We were told recently that a drone took off from Edwards AFB in California and flew to New Zealand, landed was refueled, took off and flew back to Edwards, with no pilot on board. These feats are accomplished using a combination of GPS satellite information along with automatic pilots being constantly reprogrammed from either the ground or a high orbiting mother ship. It wasn’t always this easy.

Most great inventions are born of necessity, as were the original nav aids. In the middle 1920s, the government was up to their necks in airmail delivery. Brave pilots flying open biplanes, through horrendous weather and starless nights, were being lost in huge numbers. It was obvious that when the weather was bad, a little help for the pilots was needed. Radios were still in their infancy, so the feds turned to towers with very bright lights on them, reverse of coastal light houses. Maritime pilots turned away from lighthouses, as they meant danger, aviators turned towards the beacon towers, because they meant safety. A few years ago there was still a 1920′s beacon at the 29 Palms Airport. It was a medium tall steel structure with a large light on top. The government installed these beacon towers every 35 miles or so along well traveled routes. The lights would blink with a code which told the pilot which light he was heading for. The powerful lights could be seen for 40 miles on a clear night. So pilots, mostly air mail planes, simply followed the lights cross country until they found their destination. It wasn’t perfect but it did work. During the day, pilotage was practiced. The name of the town was also painted on the roofs of large barns or buildings as well as the towers themselves.

The VOR system of Omni directional towers was started after World War II and is still being used.

The beacon light nav aid was in use until the early 1930s, when radios in aircraft became more prevalent. Next in line, the far more efficient, but quite difficult to follow radio beacons which sent out straight lines in four directions which followed popular air routes. The radio beacons were indentified with Morse code. I can still remember the code classes at Chapel Hill, NC during my Navy training days, it was hard work, but once you got it, it stayed with you. I was taught how to use this system by the Navy and when I got out I also used it to obtain my civilian IFR ticket. If you were on course, you heard a steady tone, if you drifted to the left you heard a dot dash (A)  so you corrected to the right until you had a steady tone again. If you drifted to the right you heard a dash dot (N). In theory it was pretty simple as long as you were heading in the direction of the radio beacon. This system was used until the end of World War II.

Pilots were constantly asking for a nav aid that could take them in any direction. The feds responded with the VOR system, which is still in place, but is usually second choice to the GPS nav aid that most aircraft have installed or the pilot has one in his flight bag. The new VORs sent signals out at 360 degrees and they could be used inbound or outbound. Then when the feds added DME (distant measuring devices) it became real simple to navigate any place in the world which was serviced with VOR towers. About 15 or 20 years ago I did a review on a small. hand held battery powered GPS. I forget the name, but it was long and curved and took six double A batteries. Armed with a pocket filled with batteries and two of these new GPSs we took off from APV in our F-33 Bonanza and flew to Winter Haven, FL using only the GPS for guidance. One member of our crew also monitored the VOR gauges to keep us out of trouble, but this proved to be unnecessary. Florida was overcast with light rain under the cloud cover and we flew on top until we found a hole near Winter Haven, still using the GPS, we arrived at the correct runway in a downpour without any problems at all. Our crew of pilots and writers were quite impressed to say the least. My late wife Tina and I flew ocean to ocean 27 times in all types of aircraft using VORs and later GPS as backup. In a few more years VORs will be history and super accurate GPS nav aids will be in every aircraft. Every airport, no matter how small, will also have an instrument approach, thanks to the global positioning system. Tie in a modern GPS with a modern autopilot and it won’t be long before licenses are granted to the airplane and not to the pilot.

Most aircraft and pilots either have a GPS installed or one is carried in the flight bag. It is the navigation system of the future. This is a hand held unit.

And are you aware that a child’s toy gyroscope is the main component of all autopilots, some are still mechanical but new digital ones are here to stay.

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