VOR Rated Converage

[WIKI44]

AIP GEN 2.2 lists the rated converages of nav-aids.

VOR and DME:
Aircraft Altitude (FT) Range (NM)
Below 5,000 60
5,000 to below 10,000 90
10,000 to below15,000 120
15,000 to below 20,000 150
20,000 and above 180

Shouldn't it mention the range of the navaid in terms of the elevetion of the aircraft, rather than the altitude? For example if i were to fly over BIK VOR at 5000 feet, the converage would be no way near 90nm. In fact its more likely that I would have no signal reception even at very short ranges because of the elevation of the terrain. Any suggestions?

[Icarus53]

Mate - these are rated coverages, not absolute ranges of the aid. Furthermore, aids which are subject to specific terrain issues are listed in the Nav Aids section of the Jepps with details of the aid's limits.

I'd go and check to see what the book says about BIK, but it's early and I haven't had my Weet Bix yet.:ooh:

Icarus

[go_soaring]

VHF and UHF frequencies/ranges are basically line of sight related.

General rule of thumb for VOR Range: (square root of 1.5 x aircraft height AMSL) + (square root of 1.5 x VOR height AMSL)


eg, if cruising at 12000 and the VOR is at 2000', then the maximum theoretical range would be: 188.9nm


go_soaring! instead

[Spodman]

Yes Wiki, you are right and the AIP is wrong again. Probably that is why the antenna elevation is listed in ERSA for BIK for the thinking aviator.

Erm, go_soaring, your formula needs work. If the VOR and the aircraft were at 12,000 the maximum theoretical coverage would be 268NM, rather than the SFA I would expect, (depending on the QNH).

SQRT of 1.5 x the DIFFERENCE in height between the aircraft and the VOR and you have something, like wiki suggests.

[alexthepilot]

ye as you stated AIP will not be exact, obviously. its just for planning purposes all to deal with calculating LASLT's and maximum distances between fixes thats why called RATED not ACTUAL. ACTUAL coverage is guy above stated using that formula