VOR Check

Skymac

Skymac

Pre-takeoff checklist
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Justin
A fairly pointless debate but how would you record/notate a Dual VOR check in the Check Log?

Had a person write down VOR 1 330
VOR 2 333 3*

A real particular fella then said well it should have +/-, I said why does it need those symbols? It’s simple just 3* difference.
 
Luckily, my Garmin SL30 has a VOR check record in the system menu. Just have to enter the location and date. The rest is pre populated for me.
 
FAR91.171 just says signature/place/error/date. I suppose there's a lot of latitude on how you express each one.
 
How about: VOR ck c/w Feb 31, 2025. TBD 180 deg radial, 2'000 ft. 3 deg diff. John Wayne ATP 141414.
 
That’s what I’d do, but a bored guy with 20,000 hours was arguing with me over a dumb +/-….. Aviation, lol…
 
I'll see his 20K and raise him another 3K. I say that my sample write up is time tested.
Add the DME if you want.
 
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I record the place of the check (say over airport KXXX), the VOR used (XXX), and the radials recorded for each NAV, (#1 xxx FR, #2 xxx FR). Note the variance between NAVs, date and add a signature and cert #. This gets recorded in a VOR check/squawk book (a 3 x 5 notebook).
 
I've always used a +- (but I don't think its necessary)...but its also "my plane my rules".

Funny, but for the past three or four checks, its been +-0...it was a degree or two off before that, but lately no error.
 
That reg always has a word that amuses me. It says you can do the ground checks at the airport of "intended departure." I always wonder why they qualified it with "intended."
Is this to invalidate "unintentional departures" (sort of like unintentional spins) or to bar the test at airports you never intend to depart from.
 
Maxnr said:
How about: VOR ck c/w Feb 31, 2025. TBD 180 deg radial, 2'000 ft. 3 deg diff. John Wayne ATP 141414.
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chemgeek said:
I record the place of the check (say over airport KXXX), the VOR used (XXX), and the radials recorded for each NAV, (#1 xxx FR, #2 xxx FR). Note the variance between NAVs, date and add a signature and cert #. This gets recorded in a VOR check/squawk book (a 3 x 5 notebook).
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FAR 91.171 (b) and (c) say you need to note the bearing, not the radial.

Also, (d) says you only need to enter date, place, bearing error and signature in the aircraft log or other record. I do exactly that, with "other record" being the same thing I use to copy down clearances and ATIS. I'm not sure why you guys want to do all that other stuff.
 
Skymac said:
A fairly pointless debate but how would you record/notate a Dual VOR check in the Check Log?

Had a person write down VOR 1 330
VOR 2 333 3*

A real particular fella then said well it should have +/-, I said why does it need those symbols? It’s simple just 3* difference.
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A lot of people write "+/-" when recording the difference between VOR receivers, but I don't see anything in the reg that requires that.
 
asicer said:
FAR 91.171 (b) and (c) say you need to note the bearing, not the radial.

Also, (d) says you only need to enter date, place, bearing error and signature in the aircraft log or other record. I do exactly that, with "other record" being the same thing I use to copy down clearances and ATIS. I'm not sure why you guys want to do all that other stuff.
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I agree. The FAR requires date, place, bearing error, and signature. That's it. I comply with exactly what's required.

7/9/22 ABC -1/+2 Signature

The only thing left a little vague in the FAR is "place", which could be an airport, a ground checkpoint, a VOT, an airborne location, etc. Not well defined what you need to put, so I may put ABC 180/10 or something like that. But brevity is the key.

And really, ensuring the check has been done in the last 30 days and keeping a record is only required if you intend to use VORs for your routing. Like most people with a modern WAAS GPS, I never INTEND to use them. I do occasionally check them in flight, mostly to have something to do and know if they're having problems, but that's not required.
 
Sorta trivia, but where I worked, +-3 degrees was a 6 degree zone of possible real value, or an actual 6 degree error zone.

330 and 333 would be processed as 331.5, +- 1.5 degrees.

All our definitions of required accuracy were "from xxx to yyy".

As others have described, the plane that I flew each had a 3x5 spiral notebook of VOR tests and dates. Anyone planning to fly some T&L would check the book, and update it if it was getting stale. No extra flying needed.

For RGBeard, the 'place of intended departure' rule allows a VOR check, without actually departing.
 
RussR said:
I agree. The FAR requires date, place, bearing error, and signature. That's it. I comply with exactly what's required.

7/9/22 ABC -1/+2 Signature

The only thing left a little vague in the FAR is "place", which could be an airport, a ground checkpoint, a VOT, an airborne location, etc. Not well defined what you need to put, so I may put ABC 180/10 or something like that. But brevity is the key.

And really, ensuring the check has been done in the last 30 days and keeping a record is only required if you intend to use VORs for your routing. Like most people with a modern WAAS GPS, I never INTEND to use them. I do occasionally check them in flight, mostly to have something to do and know if they're having problems, but that's not required.
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Actually, as @geezer noted, “bearing error” is pretty vague when doing a dual VOR check. Your VORs may be +/-3 from each other, but how do you (or anyone subsequently looking at your records) know that the errors aren’t 6 and 9 degrees?
 
MauleSkinner said:
Actually, as @geezer noted, “bearing error” is pretty vague when doing a dual VOR check. Your VORs may be +/-3 from each other, but how do you (or anyone subsequently looking at your records) know that the errors aren’t 6 and 9 degrees?
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You don't, and if you're doing the dual-VOR check method, you have no way to know either. I assume the thinking here is that it's unlikely for both receivers to be way off. I don't know if that's good thinking, but seems to be what it is.

Because, your VORs could both be way off but still legally meet the 91.171 requirement as long as they were both off about the same amount. One is 42 degrees off and the other is 45 degrees? Apparently good enough for 91.171. Dumb, and obviously not useful, but legal.

At least the single-VOR methods are checking against a known standard.

I have always found it interesting that for a single VOR system, 91.171 lists the options in required priority order, all with a known good radial to test against. And then goes on to say "but if you have two VORs you can ignore all that precision and do this other check with no known good radial or criteria to measure against".
 
RussR said:
You don't, and if you're doing the dual-VOR check method, you have no way to know either. I assume the thinking here is that it's unlikely for both receivers to be way off. I don't know if that's good thinking, but seems to be what it is.

Because, your VORs could both be way off but still legally meet the 91.171 requirement as long as they were both off about the same amount. One is 42 degrees off and the other is 45 degrees? Apparently good enough for 91.171. Dumb, and obviously not useful, but legal.

At least the single-VOR methods are checking against a known standard.

I have always found it interesting that for a single VOR system, 91.171 lists the options in required priority order, all with a known good radial to test against. And then goes on to say "but if you have two VORs you can ignore all that precision and do this other check with no known good radial or criteria to measure against".
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I suppose since nearly everyone has GPS these days, you could compare the GPS heading to the VOR with the VOR itself...
 
RussR said:
You don't, and if you're doing the dual-VOR check method, you have no way to know either. I assume the thinking here is that it's unlikely for both receivers to be way off. I don't know if that's good thinking, but seems to be what it is.
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I always think of that when people talk about how close I need to be when on a VOR radial.
 
At most airports that are near a VOR, you can look up the radial in the A/FD so you can verify the accuracy of your receiver when over the airport. At KHBI, my non towered airport, the 173 degree radial from GSO is what I use when overflying the field to check VORs.
 
RussR said:
That's not one of the permitted methods in 91.171.
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Nor is it necessarily accurate.

If you’re navigating by VOR, especially using airways, it’s pretty easy to tell if a VOR is more than a couple of degrees off…if you consistently see a significant CDI deflection when you switch over at a changeover point, something’s wrong. You just have to notice it.
 
RussR said:
That's not one of the permitted methods in 91.171.
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When did I say anything about 91.171? If you are checking VOR to VOR to comply with 91.171, you can THEN check VOR vs GPS for your own piece of mind.
 
Just a quick scan through the thread. I'm not getting all this +/- stuff. You check a VOR. It's either right on or it's not. If it's off, say how much and in which direction. Like +2. Or if it's off in the other direction it's -2. Any +'s or -'s aren't even needed to comply with FAR. It's nice to know info for your own use though. OP was right. That particular fella was being, well, particular.
 
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Country Flier said:
When did I say anything about 91.171? If you are checking VOR to VOR to comply with 91.171, you can THEN check VOR vs GPS for your own piece of mind.
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I assumed you were, since you were responding to my post where I mentioned 91.171 three times. But if you weren't, no big deal. Lo siento mucho.

However, I've seen VORs where the station declination is 7 degrees off from the current magnetic variation in the area. The GPS will be using the current value. Which means even if everything is working perfectly, you could still see a 7 deg difference between the VOR and the GPS. That's one of the reasons it's not allowed for 91.171.
 
RussR said:
I assumed you were, since you were responding to my post where I mentioned 91.171 three times. But if you weren't, no big deal. Lo siento mucho.

However, I've seen VORs where the station declination is 7 degrees off from the current magnetic variation in the area. The GPS will be using the current value. Which means even if everything is working perfectly, you could still see a 7 deg difference between the VOR and the GPS. That's one of the reasons it's not allowed for 91.171.
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Sorry, I wasn't meaning to sound harsh...I was replying to you saying "no way to know"...meaning w/GPS, you would know.
 
Don't know which GPS you're using, but the IFR units typically know what the declination is. While the TRK when heading to the station may disagree with the radial, if you ask the unit what the radial is, it will tell you based on your current (GPS) position and the station declination.
 
IMHO it seems that this is being "over thought." I see many opinions expressed that the VOR system is fading away. Many shutdowns. If there are no VORs in service in your area, will the VOTs and designated airport check points go away too? Could be that there will be no way to do an airborne/VOT check in West Texas if your destination is in the L.A. area. Will only the VOR part of a VORTAC go away and leave only the TACAN? Can we even upgrade to TACAN? If you are down to only the ILS, how do you comply with 91.171? Do you need to? (I believe the ILS is the "mac daddy" of procedures and outshines any GPS procedure. Ask me why.)

Oh, another thing. I have noticed that on occasion, an airborne check can be different using either a CDI or the RMI pointers on an HSI. Go with which one?

As for GPS. I wonder how secure it is. There are NOTAMS from time to time that GPS may be down in my area near Eglin AFB. Testing. Just my suspicion that maybe they wish to see how durable the GPS is during war or terrorist attack. Eglin is the USAF Armament Test Center. I assume a big reliance on GPS. A bad actor can cobble up a scrambler very cheaply.

As Forest Gump says "Thats all I have to say about that."
 
Maxnr said:
IMHO it seems that this is being "over thought....
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Yes. I mean its VORs. Once you legally log the error between 2 of them, you could check their accuracy with a dang iPad for gosh sakes...if the iPad shows you on, or even sorta on, an airway while using the VOR...voila! Accurate enough!
 
Maxnr said:
will the VOTs and designated airport check points go away too?
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Yes, this has happened in my area.

Maxnr said:
Will only the VOR part of a VORTAC go away and leave only the TACAN?
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Yep, this has happened, too (e.g. GGT TACAN, located at the GTOWN waypoint, formerly the GGT VOR; also the UCA TACAN, formerly the UCA VOR)

There is no question that the VOR system is being reduced in utility. In areas of the northeast, it can be challenging to file Victor Airways to a destination using VOR nav only due to the number of decommissioned and out of service VOR stations. Interestingly, for southwesterly departures, I often get routed to ULW, which is a permanently out of service VOR.

VOR is an important backup nav system, but the IFR system is highly GPS-centric now, and has been for a while. At non-metro airports, GPS is often the only game in town, especially with VOR approaches going by the wayside due to service issues, flight check backlogs or failures, and decommissioning. Toward the end of its lifetime the VOR approach to my home airport was Notamed N/A more often than it was available. Some area non-metro airports that formerly had LOC or NDB approaches have had those decommissioned as well.
 
asicer said:
Why?
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I was bold enough to make the flat out statement that the ILS was the best procedure and superior to any GPS including LPV. First the name. The "S" in "ILS" stands for System. Lights are part of the system. ILS most times has a lower DH & vis than any GPS procedure. And the lights. An airport mgr once told me that they were halogen bulbs. They produce heat.
May I be forgiven for telling of an experience illustrating the halogen effect.
Departure was at the crack of dawn and the terminal forecast was "Possibility of fog dissipating after 0900." But it was clear as a bell. Dropped off and picked up. Headed home about 10AM with a full load and enough gas for a nearby alternate. Looking like a milk run so far. Got the ATIS 25 mi out and fog was forming. Weird. Got Approach on the airport's RCO and requested a pop up clearance for the ILS. Over flew the airport and it was fogging up fast. As we intercepted the LOC and switched to TWR, TWR gave us new weather: Zero obscured, 1/4 mi in fog, wind calm, altimeter yada yada. Cleared for the ILS. Continued after applying FAR 97.3 (C) and AIM 10-1-2.
Co-pilot doing a great job hand flying her. I made the call outs and was eye balls out. Spotted the rabbit at about 1/4 mile away and it was like flying in a canopy of clear air. I could even see 2/3 down the 8,000 ft RW. Taxiing to our ramp was in solid fog. Almost ran into a wind sock.
Later B.S. about the weird fog and some opinions were that the halogen lights burned off some of the low fog. Much like the RAF used barrels of burning gasoline to clear fog from their RWs in WW2. It was often also observed that a 8'000' X 200' slab of concrete feet thick was an excellent heat sink and radiates a lot of yesterday's sunlight.
Another advantage of ILS is that they are mostly at airports that have rental cars and sometime hotels on the field. Nothing like the airport 20 miles from my home. Its a little improved from recent days when there were 3 GPS and 1 LPV procedures. 3 RWs had REIL. Guess which one had no lighting with a "black hole approach". Much improved today and if you're hungry, there is a vending machine. However, there are 4 ILS airports within 50 miles including one 15 miles from the one I mentioned.
 
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I have a single VOR and a modern, WAAS GPS.

I'm currently using a small cropduster airport that's along an airway as a VOR check location.

Is there a way I can use my GPS data to somehow to satisfy 91.171?
 
Rgbeard said:
But at SDM there's a great VOR-A approach that's far better than the GPS approach.
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I’ve never been there, but why do you say that? The RNAV is straight-in, has vertical guidance and much lower minimums. Even if you have to circle from it, it still has lower minimums than the VOR, except for Cat D. So what am I missing that makes it better?
 
RussR said:
I’ve never been there, but why do you say that? The RNAV is straight-in, has vertical guidance and much lower minimums. Even if you have to circle from it, it still has lower minimums than the VOR, except for Cat D. So what am I missing that makes it better?
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For the RNAV, it's a straight-in if you're coming from Japan. Assuming you're coming from the United States, you've got to fly past the airport, head out to the Pacific, and turn around, and land (95% of the time) with a tailwind, or circle to 26. Adds fifteen mins, and the whole tailwind stuff.

For the VOR, you simply fly to HAILE, turn left, pop down through the clouds and land (95%) on Rwy 26. Adds five minutes.
 
Rgbeard said:
For the RNAV, it's a straight-in if you're coming from Japan. Assuming you're coming from the United States, you've got to fly past the airport, head out to the Pacific, and turn around, and land (95% of the time) with a tailwind, or circle to 26. Adds fifteen mins, and the whole tailwind stuff.

For the VOR, you simply fly to HAILE, turn left, pop down through the clouds and land (95%) on Rwy 26. Adds five minutes.
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Okay, I can see that. Not sure I'd call it "better", but maybe "more useful for most operations" I guess. I do suppose that "more useful" and "better" are basically synonyms, so I'm able to be swayed on this one.

But if the weather is 600 overcast and 2 1/2 sm of visibility, or lower, it's pretty clear which approach is the only option.
 
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