Using GPS to do Dual VOR check

[azaviator08]

Anyone know if you can use the GPS OBS mode to do a dual VOR check? My initial answer would be no. But, I was wondering what everyone else thinks.

 

[JulietBravo]

No. "Hence.. dual VORs"

Do you have an airplane with only 1 VOR?

VOT checks are real easy as well as airborne checkpoints.

 

[FDX8891]

Anyone know if you can use the GPS OBS mode to do a dual VOR check? My initial answer would be no. But, I was wondering what everyone else thinks.

No.

 

[msmspilot]

For the legality of the 30 day VOR check, no. On the other hand, I have caught VORs that were getting bad by cross checking with the GPS. When you do the VOR check and the two disagree, which one do you tell the avionics guy is bad? Well, GPS can help with that.

 

[elmetal]

this also brings up a question I've never really had answered...

If you always do a dual VOR check, how can that be safe? I mean what if both VORs are off by say 5 degrees, but since you checked them against each other they both say everything is cool.

I don't know, I do dual VORs because it's just easier but sometimes I go out of my way to do an airborne or something of the sort in case I run into the aforementioned problem

 

[Chief Captain]

Hmmm. Off the top of my head, I can't think of which reg says that you can't use a GPS, but my gut feeling is no.

At the same time, if my VOR's start to look screwy the GPS is the first thing I'm gonna use to see if they line up.

 

[msmspilot]

Hmmm. Off the top of my head, I can't think of which reg says that you can't use a GPS, but my gut feeling is no.

At the same time, if my VOR's start to look screwy the GPS is the first thing I'm gonna use to see if they line up.

If dual system VOR (units independent of each other except for the antenna) is installed in the aircraft, the person checking the equipment may check one system against the other in place of the check procedures specified in paragraph (b) of this section. Both systems shall be tuned to the same VOR ground facility and note the indicated bearings to that station. The maximum permissible variation between the two indicated bearings is 4 degrees.

 

[BajtheJino]

Am I reading this right? If people are looking at their VOR and then checking it against their GPS they think they should match? Granted they should be really, really close...If you're flying an airway and your needles are centered and then you look at the GPS and it shows you, lets say, 2 miles left of course what would you do? Fly the airway off the needles or fly the airway off the OBS? Which one is mo' right?

 

[msmspilot]

Am I reading this right? If people are looking at their VOR and then checking it against their GPS they think they should match? Granted they should be really, really close...If you're flying an airway and your needles are centered and then you look at the GPS and it shows you, lets say, 2 miles left of course what would you do? Fly the airway off the needles or fly the airway off the OBS? Which one is mo' right?

If you tune your VOR to a station, and center the OBS with a TO indication, then ask your GPS for the bearing to the station, they should be close. Obviously the magnetic poles shift some over time and the VOR isn't retuned until it's a certain amount off. So they may not be exact. But if you have a VOR that says 360 and a second VOR that says 030, the GPS can tell you which one is not right.