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Navigatiion Methods

Pro Member Trainee
pearlygatesuk Trainee

Fairly simple question.

Why would anybody (in their right mind and fully functioning hi-tec cockpit) use VOR to VOR as a navigation method give that Direct A to B is surely the best, shortest (and therefore most cost-effective) and best method - I'm sure there IS a reason otherwise it wouldnt exist but still if one of you simmers could shed some light.

Many Thanks

Pearly

Pro Member Trainee
pearlygatesuk Trainee

Did I mention it was the best?? hmmmm

Pro Member Captain
Bindolaf Captain

One simple answer is that if everyone starts flying from point A to B (to C, to D, E, etc.) willy nilly, direct or curvy or zig-zaggy there will be as many air traffic accidents as there are car crashes. Thus, aircraft (at least under IFR) use airways, many of which are defined by VORs. And VFR planes can go wherever, but at specific altitudes and around specific areas (airspaces) where they pose no danger to other traffic.

Would it be simpler to have RNAV or GPS navigation? Sure! Except not all aircraft have GPS (let alone RNAV or FMC) and not all countries (or even regions of countries) have the beacons and radars necessary.

Pro Member First Officer
JTH First Officer

Bindolaf, now that you mention airways I have a question. My understanding of airways is that they are a collection of VORs, and just save ATC the time of calling out all the different VORs and headings. So there may be five VORs that will bring you from City 1 to City 2 (bearing in mind of course that you fly them at the correct radials) - but instead of listing them all we just say Airway Alpha or something (or do they have longer names like A134 or something like that)?

Thanks in advance for any clarification on airways. JTH Smile

Don Wood Guest

The short answer is VOR and direct navigation are both used often. GPS is becoming more popular and more affordable but there are still many general aviation aircraft not so equipped and many pilots not trained in its use. (Caution: flying GPS in Flight Sim DOES NOT train you to fly GPS in the real world). Even with GPS, many flights cannot be done direct because of intervening restricted or prohibited areas, and at low levels, other controlled airspace.

I don't fly with GPS but as an example, if I had GPS in my aircraft and wanted to fly from here (Mesquite, NV) to Reno direct, at most times I could not do so because I would have to fly through the Nellis military restricted areas and they are usually hot and unavailable for civilian traffic. So, when I fly to Reno, I have to make wide detours to avoid the restricted areas and would have to do so even if I had GPS.

JTH: An airway is usually longer than the defined path between two VORs and each airway is named. The low level airways in the US always start with "Victor" or "V" on the chart and ends with a number. A defined airway may be cosiderably longer than the distance between two VORs. For instance, an airway may begin at one VOR, run to a second then a third then a fourth, and terminate a fifth or more. Just one example, V27 runs all the way from San Diego to Seattle and is defined by at least a dozen VORs. The course between VORs on each segment may not be the same between one VOR and the next and, in fact, courses can an do change in the middle of a segment at an intersection.

In VFR flight, many, maybe, most flights are done off the airways. As long as you do not penetrate controlled, restricted, or prohibited airspace, you can fly anywhere you want to in the US without even talking to ATC. For those kinds of flights, VOR's are often used for navigation.

Don Wood Guest

I neglected to mention in response to JTH's question, airways are also used for routing clearance in IFR flight plans and for planned route of flight in VFR flight plans. Using the example in my previous post, If I wanted to fly from San Diego to Seattle (assuming I had the fuel and my butt could stand it), my entire route of flight on my IFR flight plan could be SAN-MZB-V27-SEA. Receving that clearance, ATC would assume that I would then take off from Lindberg Field in San Diego, fly to the Mission Bay (MZB) VOR and then make all the correct turns to fly to each VOR along V27 enroute to Seattle using the correct course. On arrival, I would expect to receive an IFR clearance for whatever runway ATC wanted me to use for landing or, I could request a specific landing clearance when I started talking to Seattle Approach.

Pro Member First Officer
JTH First Officer

That's really explained it, thanks a lot Don. Is there anywhere that lists all the different airways across the U.S. just so I could get an example of where the other main ones are? Or are there two many of them for that to be practical?

Pro Member Chief Captain
RadarMan Chief Captain

JTH wrote:

That's really explained it, thanks a lot Don. Is there anywhere that lists all the different airways across the U.S. just so I could get an example of where the other main ones are? Or are there two many of them for that to be practical?

Here's a nice site that list airports all over the world, just pick the country you want.

http://worldaerodata.com/countries/

Radar

Pro Member Chief Captain
Greekman72 Chief Captain

Great site RadarMan. Thumbs Up! Thanks a lot. Exclamation

Pro Member First Officer
Corgi First Officer

Radarman,

That's just what I've been looking for.

Thanks a lot

George

Thumbs Up!

Pro Member First Officer
JTH First Officer

Thanks Radarman but I was talking about airways not airports Smile

Pro Member Chief Captain
RadarMan Chief Captain

JTH wrote:

Thanks Radarman but I was talking about airways not airports Smile

Sorry, my eyes must have been playing tricks on me. Sometimes we see what isn't there.
Nice link anyway. Laughing

Radar

Pro Member First Officer
lkw First Officer

You need to get a hold of some sectional maps. http://www.ranainside.com/ is one way to get sort of a virtual version.

The charts can be obtained from AVSIM search on Matt Fox for packs of the United States. Other maps can be added by calibrating moveing map
I think I noticed some maps of France just now and I am sure other all available on AVSIM.

Don Wood Guest

There are hundreds, if not thousands, of airway segments just in the US. If you want to get some idea of how thick they are, make friends with an instrument rated pilot or instructor and ask to look at his/her Low Altitude Flight Planning Chart. It will make your eyes pop! You may also be able to buy one from Jeppesen. I don't know if they sell them separately or not.

Pro Member First Officer
HardLanding First Officer

Related question: Is a Victor airway always a straight line between VOR stations, or can it deflect at some point defined by (I guess) distance measuring equipment?

HL

Pro Member Captain
Bindolaf Captain

There are airways (both Victor and Jet if not mistaken) that are defined "VOR to VOR". There are others that are RNAV airways, which means there are no (or few) VORs along the way and the airways are just lines between intersections, calculated by Lat/Long by the FMC. In both cases, an airway need not (and rarely is) a straight line. It's more a segmented kind of jagged line.

Don Wood Guest

I'll have to defer to someone who knows more than I do about airways formed by GPS or RNAV waypoints. However, using VOR, not all airway segments are straight lines. A change in course along an airway can occur at either a specified DME distance or an intersection defined by the airway course line intersecting a defined radial of some other VOR, usually not on the airway itself. Radial instersections are much more common because many aircraft are not equipped with DME.

Picture an airway where you have to fly outbound from VOR A to an intersection, then make a 30 degree course change and fly to VOR B along one of its radials. That intersection will usually be defined by an intersection with a radial of VOR C. I am not aware of any examples but I suppose an intersection could also be defined by passing over an NDB.

Pro Member First Officer
HardLanding First Officer

OK, and thank you. That makes good sense to me. My only sectional is the one for New York, which is very crowded. and I still have some trouble matching up the information with what it refers to.

HL

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