Instrument approaches

[Mickel 42]

Folks

 

Part in preparation for a certain sim airliner maker releasing a DC-6 and part nostalgia, I fired up FS9 yesterday and flew a couple of Cal Classic birds up and down the US west coast. In the days before INS, let alone RNP, how did airliners approach airports? Did they simply turn up on a radial from where they came and get vectored from a point to an ILS, or descend DME steps until visual and then circle to land? Or were there STARs of a fashion using VORs and NDBs (thank heavens for a navigator!)?

 

Subsequently, when did STARs become common place? Was an INS accurate enough once there were ground stations in range, or were they too slow/cumbersome to program to be worth it.

 

I know this corner of the forum is pretty dead, but hopefully it will hang around in the recent topic list for someone to grab it for me...

 

Cheers

 

Mike

[g_precentralis 191]

Well, radio navigation (and instrument approaches) existed well before WWII, but only after the war, when ICAO was established, VOR/DME and ILS were adopted as standard navigation aids. There were several long range navigation systems around the world, but the first truly global long range nav system was Omega (you can read wiki for details). INS was introduced in civil aviation later.

 

To give you some time reference in Europe:

-After WW2 it was really chaotic. 

-Series of meetings were initiated to regulate airspace, and try to release some kind of AIP. 

-In early and mid fifties, they finally introduced some order, expanded VHF aviation channels from 5 to 20, introduced flight corridors (airways), installed navaids, and started to provide radar coverage around big airports...

-Airspace as we know today was introduced in late fifties and early sixties. They opened upper airspace up to 40k feet, they introduced flight levels (based on QNE). Without RVSM we have today, above FL290, vertical separation was 2k feet.

 

INS and Omega were not precise enough to provide terminal guidance. I imagine standardized terminal procedures arised when AIPs were introduced and worldwide distribution ensured. 

[Mickel 42]

That pretty much covers off the high level stuff, thanks. What I'm really after is the nuts and bolts of the approaches, rather than the ENR. I have a feeling there were a lot of NDBs at the tops of ILSs that no longer exist, and a lot of DME stepping. Looks like I'll have to wing it - or research a lot more. Wiki isn't terribly helpful, unfortunately.

 

Mike

[Great Ozzie 101]

Mike,

Interesting subject... I did some poking around...

This wiki on low-frequency radio range might answer some of your questions.  I'd imagine DC-6s would have navigated cross-county using this type of navigation. Another type of (possible) navigation would be the type that should have been used by (the ill-fated) TWA Flight 3 (i.e. airway beacon ).

Given when INS came into existence (also same for Omega Nav - check the Wiki) I would imagine the DC-6 pre-dates INS for the most part. Here's a thread at airliners.net on Early Transatlantic Jet Navigation that may be of some use. http://www.airliners.net/aviation-forums/tech_ops/read.main/260400/

VORs I don't think came into use until the mid-50s or so.  The FAA did not come into existence until 1958 (see: A Brief History of the FAA).  One of their charges was to set up a safer NAS (National Airspace System).

As far as approaches, yes, there were at one time many NDB approaches, and NDBs were used (maybe still some) to I.D. the FAF (i.e. Compass Locator / LOM i.e. Locator Outer Marker) on the ILS.  No idea when DME came into use.  By happenstance today, while watching the 1954 film The High and the Mighty, I heard mentioned they were going to fly in on the ILS (and there was a compass locator ).

ASR (Airfield Surveillance Radar) seems did not come into use until the '60s (based on this website: Radartutorial.eu).  I'd imagine aircraft were tracked with 'paper strips' and had to make position reports from time to time.

Here is a paragraph I found on SIDs & STARs in the Instrument Procedures Handbook: When the repetitive complex departure clearances by controllers turned into standard instrument departures (SIDs) in the late 1970s, the idea caught on quickly. Eventually, most of the major airports in the U.S. developed standard departures with graphics for printed publication. The idea seemed so good that the standard arrival clearances also started being published in text and graphic form. The new procedures were named standard terminal arrival routes, or STARs.

 

Wow... just tried a search on "history national airspace system" and came up with the following site: http://blog.cwam.org/2009/02/history-of-us-national-airspace-system.html Very nice description I think.  It corresponds with my aviation experience which started in the mid-80s (mentioning things like Control Zones, PCA, LORAN etc.)

 

-Rob

[Mickel 42]

Thank's Rob! I've read the first link and the last. I'll get to the rest in due course. Me thinks I'll stick to ground based navaids for now.

 

I'd forgotten all of this applies to a certain Stratocruiser model as well (one that I should be using a lot more often). I think I need to stay away from the magenta lines for a while and get practicing.

 

Cheers

 

 

Mike