Formula for Distance from VOR

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Mac
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Formula for Distance from VOR

Post by Mac »

Can anyone tell me the formula that is used to calculate distance from the VOR by turning and crossing the radials?
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Grey_Wolf
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Post by Grey_Wolf »

Can anyone tell me the formula that is used to calculate distance from the VOR by turning and crossing the radials?
Sure :D

Time to Station = Time to Cross Radials in Seconds / Number of Radial Crossed

or if you wish

Distance to station = ( GS x Time in Minutes ) / Degree of Bearing Change
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Post by Cat Driver »

My question is why would you need to know this?
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Post by Doc »

Turn on the DME? I'm sorry, I couldn't help it...
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Mac
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Post by Mac »

Thanks Grey Wolf.






Cat Driver wrote:My question is why would you need to know this?
Could have been useful dealing with a lost VFR aircraft, VOR only, with no transponder.
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Post by Cat Driver »

Could have been useful dealing with a lost VFR aircraft, VOR only, with no transponder
Does that happen often?
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Post by 4Stroke »

From what I've heard,a lot of VfR/IFR tower units have disabled their VDF in favour of radar......so if you have an issue, dial up 126.7, and ask for help, or dial up nearest ARTCC and sqwuak IDENT.

I've heard this happen to a buddy, pre-PPL, got stuck above a layer, called up London radio, got the freq for YYZ atc, and got on radar, vectors for home.

When I was instructing, I made it a point to ensure any students going for a 'walk outta the zone' had an idea how to cope with FIC and YYZ ATC
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Mac
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Post by Mac »

Cat Driver wrote:
Could have been useful dealing with a lost VFR aircraft, VOR only, with no transponder
Does that happen often?
It did today. May never see it again but its good stuff to have in the back of your head.
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Post by Falken »

not to mention that they ask questions about it on the commercial exam...
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Post by . ._ »

Cat Driver wrote:My question is why would you need to know this?
It's on a test.

Yes Cat, I took the bait. :lol:
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Post by Cat Driver »

I figured someone would istp.....

What I was trying to point out is don't get to involved in mental mastrubation when going through the exam thing....

Because a lot of it is Alice in wonderland stuff, that you " should " never need to know.
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Post by Tango01 »

I think more VOR and ADF work should be taught at the PPL level. Some schools don't even cover it at all, but NAVAIDS are very useful tools for the VFR pilot too.

Instead of that formula, why not use 2 VORs or get a LOP and use your chart?
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Post by trey kule »

Doc wrote:
Turn on the DME? I'm sorry, I couldn't help it...
That is so 20th Centruy. The correct anser is tune the GPS to the VOr and read the numbers.

Amazing that someone had to actually use this in this day and age. I would really like to have him post the full story including where it happened and when.
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Post by Hedley »

I've been flying for 30+ years and never had the occasion to use this formula (calc dist from vor from time to cross radials).

Has anyone else?

A far more useful formula, is what distance I can receive a VOR signal at, given my altitude.
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Post by trey kule »

Hedley.

Me either. And actually when I saw this thread, I thought that is what the question would be.

I am still puzzled as to what exact cicumstances occurred to require this bit of aviation trivia.

and....is it still a question on the exams?
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Post by Hedley »

yeah, a far more relevant question might be:
You are cleared direct to VOR XYZ, which is 180 nm distant. You are at 8,000 AGL. Because you are unable to receive the VOR signal at that altitude, you request a vector from ATC until able direct via your own nav. At what distance from the VOR would you expect to start receiving at signal from it?

1) 90nm
2) 110nm
3) 130nm
4) 150nm
Another sly (and relevant!) question would be:
When is too much altitude a problem for VOR reception?
I guess it's too much to ask, to have useful questions on tests.
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Post by Grey_Wolf »

and....is it still a question on the exams?
Yup,

and as for recepetion distance:

1.23 x srq root of altitude in feet

:wink:
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When is too much altitude a problem for VOR reception?

Post by Captain CADORS »

Just curious Hedley, but is too much altitude a problem when one begins to pick up signals from another VOR with the same frequency? No doubt the zone of ambiguity would be greater directly overhead the VOR at high altitudes. Correct?

Thanks for getting the rusty wheels turning again!

- MG -
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SeawingsUAE
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Post by SeawingsUAE »

Hey Cat,
ya agreed, "should" never need to know, unfortunately does not translate into "do" need to know for exams.
I have just done my JAR ATPL airlaw and human factors exams after 26 years of flying, and 7 years 747 command,
let me tell you, about 99 % is "dont" need to know stuff, but all the same, its there!!
Do we use it day to day, real world? nope.
truth is the guys writing the exams are hardly real world people.
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Cat Driver
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Post by Cat Driver »

Yeh Seawings, how well I know.

A few years ago I wrote the FAA Comercial Gyroplane Pilot License exam.

There were seven... seven!!! questions on time and distance problems using the ADF.....

Makes one wonder if the idiots who write these exams have figured out that in the twenty first century it is highly unlikely we will be fu.king around with finding distance to a station using the ADF....

PS:

You an expat in the UAE??
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The hardest thing about flying is knowing when to say no


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Post by ei ei owe »

If it weren't for the crap questions and lousy answer options on the TC tests there'd be no way in hell I'd be the pilot I am today!
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Cat Driver
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Post by Cat Driver »

If it weren't for the crap questions and lousy answer options on the TC tests there'd be no way in hell I'd be the pilot I am today!
You are truly that brain dead a pilot???? :smt017
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ei ei owe
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Post by ei ei owe »

Not brain dead. More like a sleuth that reads between the lines and wanders between "incorrect", "correct" and "marginal" on test answers that were made up by brain dead pen pushers.
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Post by LH »

Cat Driver -------are you trying to tell me that ithere's no such thing anymore as "a cone of silence". Surely you are jesting? :lol: :lol: :lol:
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Post by Cat Driver »

Shhhhh LH....

Before you can find the cone of silence you have to use the 90 degree fade method of orientation to get headed in the correct direction...

Maybe someone who designs these exams for Transport can put that one in the exams....

Every bit as useful knowlege as the time and distance stuff they want you to know now. :drinkers:
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The hardest thing about flying is knowing when to say no


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