VOR Radial RNAV
Here it is essential you understand the difference between the various Q codes.
QUJQUJ —True bearing from an aircraft to a beacon or station is the true bearing from the aircraft to the beacon ("True to" the Union Jack can help you remember this.). The opposite of this is QTEQTE —True bearing from a beacon or station to an aircraft ("True Exit.") To get from QUJQUJ —True bearing from an aircraft to a beacon or station to QTEQTE —True bearing from a beacon or station to an aircraft or vice versa, you add or subtract 180°, as they are opposites.
The magnetic equivalents of these are QDMQDM —Magnetic bearing from an aircraft to a beacon or station (magnetic bearing from aircraft to beacon) and QDRQDR —Magnetic bearing from a beacon or station to an aircraft (magnetic bearing from beacon to aircraft). Again, QDMQDM —Magnetic bearing from an aircraft to a beacon or station and QDRQDR —Magnetic bearing from a beacon or station to an aircraft are 180° apart.
To convert from magnetic to true, you use variation. Firstly, you need to know which variation to use, as the examiner will frequently give you two.Remember here that the variation used is "where the work is being done" - so for an NDBNDB —Non-Directional Beacon/ADFADF —Automatic Direction Finder assembly, the work is done at the aircraft, so use variation at the aircraft. For a VORVOR —VHF Omnidirectional Range, the work is done at the beacon, so use the variation at the beacon. It is almost certain one of the wrong answers will involve the mistake of using the incorrect variation.
Now you have the correct variation, you now need to know which way to apply it. The saying here is "variation west, mag is best (as in, a higher number), variation east, mag is least." So if variation is west, you add variation to true bearing to get mag bearing (as mag is "best" - higher) whereas if variation is east you subtract that value from true to get mag (as mag is least).
Another way of solving this is to draw a Mag-Variation-True table (in that order) treating a westerly variation as a negative, and an easterly variation as a positive. So if the mag bearing was 100° and the variation 10E, then you have 100, +10, ?, making the true bearing 100 + 10 = 110°.
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