Small nav Q

[Cron]

Have much struggled with below Q (which could be incorrect) and would appreciate some help and quidance.

Thanks in advance.


An a/c is over position A (55 30N 060 15W), where B VOR (53 30N 060 15W) can be received. The Mag var is 31W at A and 26W at B. What is the radial from B?

a) 028
b) 332
c) 031
d) 208

[Gillespie]

As the VOR is on the same Meridian directly south it's on the 360 True radial from the VOR. With VOR's the variation is taken at the station which in this case is 26*W. Meaning your mag bearing from the station is 360* + 26* (variation west, magnetic best) giving you an answer of 026*. This is not an option which is typical of the CAA so I'd go for answer a) 028 which seems to be the closest.

If I'm off the mark here, please let me know.

Hope this helps.

[Send Clowns]

A radial is a magnetic bearing from the VOR (sometimes known as a QDR). The true bearing from the VOR is 000°, as they are on the same meridian but the aircraft is at a more northerly latitude. Apply variation to find the magnetic bearing, using variation at the VOR (this is a diectional beacon, therefore all bearings are related to magnetic meridians at the beacon), which is 26°W. 000°T becomes 026°M, which must be the radial. None of the answers match, so someone has made an error somewhere!

Hope that helps

Send Clowns
Gen Nav Instructor,
BCFT

[Cron]

Thanks both, suspect Q. Now I understand.

[oxford blue]

I have seen what I believe to be the original source for the question. In that version, the variation for position B is 28W.

[Charlie Zulu]

Glad everyone else thinks there is an error here as I also got 026(M) by the same methods above.

Was getting worried that I was doing something silly myself, considering I'm taking the General Navigation exam soon.

[Piltdown Man]

This question is really about "Does the information about which radial you are on depend on the position of the VOR or the position of the aircraft?" Answer: The VOR. From memory, it's the other way round for NDB's. But as I've promised not to use them, it doesn't matter.

[2R]

You would have to be fairly high up to get a VOR at 120 miles away .Error of vor's at 120 nm plus minus 4 /6 degrees could be a) or c) depending on your equipement and what your vor test for your a/c say the correction to be .ambiquity at work.

[Piltdown Man]

Getting a VOR at 120 miles is not uncommon. Getting a track around Europe which you follow for 120nm, now that is uncommon! And as for actually using the things - well that's done less and less.