VOR Receiver Check on the ground?

[Erice]

Can I use a published airborne VOR receiver checkpoint on the ground to satisfy the 91.171 requirement? There is a checkpoint around here that is published as 1200 msl over the intersecting runways at an airport. Could I just taxi out to that intersection and note the accuracy of the receiver from there?

My first reaction would be NO, from reading the excerpt below, but I had a CFI tell me I could . . .

(3) If neither a test signal nor a designated checkpoint on the surface is available, use an airborne checkpoint designated by the Administrator or, outside the United States, by an appropriate authority (the maximum permissible bearing error is plus or minus 6 degrees); or

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Yamaha RD250

 

[rpadula]

I'd agree with you. What was the CFI's justification for saying you could?

 

[poadeleted20]

Outside of anything else, the odds of being able to receive on the ground a VOR which requires 1200 feet for the checkpoint are pretty near zero. In any event, airborne means airborne -- it has not been checked from the ground or it would be published otherwise.

 

[TMetzinger]

The only way this would work is if you were using the particular VOR for a dual receiver cross check. If you could get a signal, get CDI #1 to center, then do the same with CDI #2, and they're within 4 degrees, you're good. But that works with ANY VOR you can receive. If you've only got one receiver, you need to be airborne.

 

[gismo]

Can I use a published airborne VOR receiver checkpoint on the ground to satisfy the 91.171 requirement? There is a checkpoint around here that is published as 1200 msl over the intersecting runways at an airport. Could I just taxi out to that intersection and note the accuracy of the receiver from there?

My first reaction would be NO, from reading the excerpt below, but I had a CFI tell me I could . . .

All airborne checkpoints have an altitude specified and AFaIK you are supposed to be at that altitude when making the check. It does seem likely that it would work pretty well at higher altitudes within the VOR's service volume but using an airborne checkpoint below the stated altitude let alone on the ground is likely to make for an inaccurate check. VOR signals are affected by terrain and surface features and any signal received on the ground from a VOR more than a mile or two away is likely to be very inaccurate.

 

[nosehair]

It could be that this particular CFI knows this particular airborne VOR check works just as well on the ground; that could be it. But, of course, that isn't really legal, and if this is the case he should be telling you that. This is a good example of the kinds of deviations you will see throughout aviation: A standardized procedure that works anywhere all the time, but can get changed on a local level without compromising safety, so it becomes "standard".