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balaton
9th Aug 2010, 14:57
Hi Everybody,

I've been on pprune for a couple of years now but this is my first thread in this topic.
Looking for any kind of source: books, personal memories, websites, etc dealing with the US ATC system around 1945-1950. Particularly interested in the airway system, navaids, airspace structure, and procedures.
Any help is highly appreciated.
b

Squawk7777
9th Aug 2010, 15:18
This might not be of much help, but I had gotten a vague idea from Ernest Gann's book "Fate is the Hunter". There's no exact reference to the date/year, but the first chapters refer to his flying before WW2.

balaton
12th Aug 2010, 11:59
Many thanks, I'll give it a try.

411A
12th Aug 2010, 14:35
US ATC circa 1945-50.

A very brief synopsis.

No radar, except at large terminal areas, therefore, procedural traffic separation in force.
Airways navigation by LF radio range and NDB's until about 1949, when the first few VOR's began to appear...thanks mostly to the efforts of Reed Pigman, and (later on) his company, American Flyers Airline.
A mixture of LF and VHF used for ATC communication.
All control towers had LF, and this was used extensively for pilot ATC communication.
No 'fancy' airspace structure as we have today, however there were control zones around airports with control towers.
Enroute traffic separation was mainly LF communications with the respective airline companies operational center, which then passed on the aircrafts position, ETA's (etc) to the regional CAA office, who then determined separation, and these instructions were then relayed by land line back to the respective airlines operational center, who then passed along these instructions to the airplane.

More questions?
Ask, and I shall attempt at answering, as best I can.

balaton
12th Aug 2010, 19:58
411a,
Excellent summary ! Some short questions:
- Did the "classic" TWR/APP/ENROUTE structure exsist at that time?
- Was some kind of simple route structure established with reporting points, airway names, etc.?
- Were there some basic flight plan form in use?
Appreciate your help,
b

411A
13th Aug 2010, 02:09
- Did the "classic" TWR/APP/ENROUTE structure exsist at that time?
- Was some kind of simple route structure established with reporting points, airway names, etc.?
- Were there some basic flight plan form in use?


Classic route structure did exist, however, not nearly as complicated as today.
For example, there was no high level airways, as there were no 'high level' airplanes flying...the highest was 21,000 feet with Stratocruisers and (later) DC-7's.
When a tower had VHF, the frequency was normally 118.1 or 118.3.
Approach control was normally 119.7 at nearly all locations, which handled both approach and departure traffic, IE: no separate departure control.
Enroute ATC was normally LF, or....ARINC VHF, which was airline company funded and operated.

Airways were labeled using the old color designations, red, blue, amber, green, white...followed by one or two numbers.
Victor airways (using the 'new' VOR's) were not established until about 1950.

The standard CAA flight plan form was very similar as in use today, in the USA. Each airline company, as you might expect, had their own flight log forms (manually generated PLOG).
There were no computer flight plans available, these were originally developed by R. Dizon Speas, toward the late 1950's, however, were very expensive, at the time.

Note, ILS was available at large major airports (as was PAR) as ILS was developed jointly by Sperry and the aforementioned Reed Pigman, in 1938.

Not all airline airports had a control tower, of course, however, those that did not normally have a control tower, had a Flight Service Station (FSS) on the airport, which co-ordinated (but did not positively control (IE: issue takeoff and landing clearances) to flights...the VHF frequency was 126.7 at all locations.
These FSS's also offered flight plan filing and weather facilities for pilots, both general aviation as well as airlines.

balaton
14th Aug 2010, 19:09
411A,

Really great ! Worth hours of digging in our library. Basically all I wanted to know.
Best rgds,
b

VX275
14th Aug 2010, 19:50
In my archive have a copy of a US Army Air Forces Pilot's Handbook for the North Atlantic which dates from the end of WW2 in europe. As others have said the procedures for the routes were all based on radio bearings on ground stations. The film of Ernest K Gann's 'Island in the Sky' with John Wayne was recently shown on UK TV and it shows the use of these radio bearing procedures quite well.
The airfield and letdown plates in the handbook at first appear familiar to modern ones until you realise that these complex maneouvres were to be flown without the aid of ground radar. The thought of flying up a Greenland fiord in cloud using only a radio compass and a stopwatch gives me the shivers.

seacue
15th Aug 2010, 06:07
Not being an aviator, but being interested, I wonder whether 3105 "kilocycles" (kHz) had a place in US commercial aviation. I remember a cockpit tour of an Eastern Airlines Martin 404 (?) in 1953 where our guide commented on the great improvement of VHF comm vs 3105.

I have a few US sectional charts from the early 1950s. There were still a few VAR ranges at that time. A quick look at the Boston Sectional dated July 5, 1951, shows at least two VARs [Nantucket 109.1 and Moosup 108.7]. Their audio A-N courses were spaced 90 degrees from the visual Blue-Yellow courses. That chart shows *NO* VORs.

Boston "Logan" airport shows 378 kHz, 118.1, 118.3 and 126.18 MHz. The Boston range was on 382 kHz.

Our experimental ground-air digital data link was on about 134 MHz IIRC. We had it coupled to the autopilot on the project's aircraft at least a few times. That was in 1952 [I think].

[15 Aug] Edited to add:

I've found a May 1960 version of the Boston Sectional chart. The VARs have gone. That on Nantucket is replaced by a VOR w/ DME. There are still plenty of 4-course LF/MF ranges. Some define airways, but there is generally a VOR-based on essentially the same route. Boston Logan airport still shows GCA ILS DF with comms on 278 kHz and 118.3 126.18 and 257.8 MHz.

Noyade
16th Aug 2010, 10:04
Note, ILS was available at large major airports (as was PAR) as ILS was developed jointly by Sperry and the aforementioned Reed Pigman, in 1938.Early post-war diagram?

http://img94.imageshack.us/img94/2046/ils3658988.jpg (http://img94.imageshack.us/i/ils3658988.jpg/)