VOR Receiver error

MNFlyboy

MNFlyboy

Well-Known Member
Hi y'all,

I've heard mixed opinions and looking for rote references if available. After completing a VOR Receiver check for IFR operations, let's say it was a VOT check and the error is +2° (182° to indicated, 180° to desired per the check procedure). While flying an airway under IFR flight rules, if the airway course is 110°, do you fly with the 110° obs course, or do you incorporate the +2° error and fly with a 112° obs course?

Common sense would say that I would incorporate the error so that way I can fly more precisely over the centerline of the airway which also prevents further chastisement from the ATC controller.

I know we will have a variety of opinions, but I need help citing written sources, so if able, please provide those resources.

Mahalo in advance
 
I don't think there's a rule or published guidance on this. It would be difficult to come up with one considering the various accuracies of the different types of checks. Airborne check with a 6° permissible error? Dual VOT check with a 4° spread (is one of them spot on; the other off 4°; which do yo follow?).

You are welcome to compensate for the error if you want to but the allowable error tends to coincide with the protected width of an airway, so it's not a safety concern. And from a scanning standpoint, seems to me to be far mfore natural (and therefore less prone to error) to correct to keep the needle centered than to correct to keep it, say, one dot left of center.
 
I agree with the above as well. Fly with the needle centered. I assume that if your VOR is within tolerances of the check, then you will remain within the protected airspace of the airway lateral confinements. I also assume the eggheads who designed this stuff took that into account when creating the service volume limits. Thinking along those lines, if you are outside the service volume limits of the VOR, then you cannot be guaranteed protection from obstacles.
 
The trouble is while operating in high traffic areas, ATC starts giving correction headings with a one dot off course indication. I have found that if I incorporate the error into my obs (desired course +/- error) I maintain a better centerline precision, and have less arc inquiries. If I fly the desired obs without the error (centered indicator), I begin flying off centerline and then the atc corrections start coming. They definitely won't give me 4miles either side. In fact, they are adamant that any deviation south of a specific Victor airway is unacceptable due to arrival traffic etc.
 
z987k said:
I think the real question is who flies airways?
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It's Hawaii, man. I fly airways here pretty much every day, and I'm medevac! The airspace is just stupidly busy all the time and I think ATC has just given up and decided to sequence everyone with airways.
 
moxiepilot said:
I agree with the above as well. Fly with the needle centered. I assume that if your VOR is within tolerances of the check, then you will remain within the protected airspace of the airway lateral confinements.
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I don't have an answer, but according to my limited understanding of trigonometry a VOR receiver with a 4 degree error would put you 4 miles off course (lateral boundary of the airway) at about 57 DME. I don't know what type of aircraft the OP flies but that could be an issue on J routes.
 
I got this today with a student: "sir ur 1/2 mile north of the airway is everything ok?" It's tough to teach a student how to account for the error when they may correct the opposite way and be twice as far off course. It's also tough to explain to a student why atc gives these calls when we're still within the airway.
 
If you have two VOR receivers, use both and split the difference. 1/2 mile really isn't anything to worry about, especially if you are a considerable distance from the VOR, if my math serves me right, that would only be 1 degree off course at 30 miles out. I wouldn't try to get them to account for any error, just have them fly with the needle centered. I think ATC gets used to people flying airways with GPS, and staying right in the center. Just tell them you're doing fine, and be sure to thank them. You'll be glad they're watching if something goes haywire for real.
 
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