After sharing some early aviation history with old NFO, he suggested I do a blog entry.
One
unchanging challenge in aviation is finding your way from one point to another
without getting lost. For non pilots, this may be puzzling. Show me any pilot
who claims he/she hasn’t been lost, and I will show you someone who’s veracity
is suspect.
Today’s
newer airliners and many General Aviation airplanes have “Glass Cockpits”.
Using several different transmitted date sources, including GPS, and along with
sophisticated autopilots, they will nearly fly themselves. In the case of some
advanced drones, they will fly themselves. For those who want more information.
The early
developer of air navigation systems was the U.S Postal Service in the 1920’s to
support their airmail service. First came ground markers, large concrete arrows
placed along routes. Some have survived.
Next came
lighted beacons, lighted airports, and rudimentary aircraft lighting. Akin to
the Pony Express way stations, if you will.
Some of these operated into the late 1950’s. I can remember seeing them in Wyoming as a child. Some were left at higher elevations to aid night flight terrain clearance.
The twin challenges of weight and reliability in equipping airplanes with radios started to come together in the 1930’s. This led to the development of radio ranges and radio beacons (Automatic Direction Finders – ADF).
The range system was later refined into the Omni Directional Navigation System (OMNI) still used today. With the proper equipment, OMNI will give you the distance to the station. With ADF, you have an indicator pointing toward, or away, from the radio station. In general, you need bearings from two ADF transmitters to locate your position. You can do the same with two separate OMNI stations.
Another newer aid was LORAN, a system using two Low frequency transmitters many miles apart, and timing the difference between the two transmissions reaching you. Considerable math is involved if you receiver can’t do it for you. LORAN will cover vast areas but is subject to things like sunspots and isn’t terrible precise. A version was used by the British in WWII to guide their bombers over Europe.
At airports
(and on aircraft carriers) are aids to help the pilot’s approach. One, glide
slope, provides vertical guidance as to the preferred descent profile. The
other, the localizer, provides left/right guidance. Two other transmitters
complete the system, the outer and middle markers. These help you judge your
distance from the runway. This system allows approach to landing operations in
poor visibility.
In all
cases, the first pilot requirement is to fly the airplane. Asiana 214 is one example of what not to do.
For all you professional pilots out there, the CFIs and those with thousands of hours of PIC time, please remember I was a lowly Cessna/Piper driver before you pick the post apart.
That said, I can beat any of you in a conventional gear spot landing contest. Oh yeah, still have the swagger!
8 comments:
Great piece! What I find interesting, as a HAM radio guy, is that the aircraft bands are still on AM bands. Hardly the most efficient for communication.
If I were to guess, the cost of moving a whole industry and private flyers to something else is cost prohibitive.
You have identified one of my many knowledge gaps. I do believe most communication is FM, or at least High Frequency. In any case, line of sight.
Nope, still running on AM. I'm sure it has everything to do with money. I'll monitor them on occasion when I'm bored with other things.
110-130mhz
Shudder at the cost of redoing all the avionics in the world, not just the USA. You can easily spend more on avionics than the airframe and engines.
LOL, great post! Thanks for putting this neat piece of history up!
Actually it's for ADF/NDB's you can ADF a radio station in a heart beat... Hell, we've done that before crossing the pond when the nav sucked. ADF on KGO radio in San Francisco worked like a champ!
You are welcome. Thanks for the suggestion.
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