Settle a Debate-VOR Checks?

[Rick James]

Well guys/ gals, it seems that we're all in agreement. My position is that it's an easy thing to accomplish so you may as well do it. I'm up against a CP that challenges me to prove that we have to, by regulation. Frankly, I've lost my motivation to argue the point and I'll just sit back and let it go.

 

[RipCurl]

BoilerUP hit part of it: if your GPS is a TSO-c129 unit (non-WAAS/non-stand-alone RNAV), then you must have an alternate means of navigation:

(b) Aircraft using GPS navigation equipment under IFR must be equipped with an approved and operational alternate means of navigation appropriate to the flight. Active monitoring of alternative navigation equipment is not required if the GPS receiver uses RAIM for integrity monitoring. Active monitoring of an alternate means of navigation is required when the RAIM capability of the GPS equipment is lost.

This only applies if this is a TSO-c129 GPS. This means a regular old GPS that can only shoot LNAV approaches. Since the VOR is required by the above paragraph, it must be tested every 30 days as per 91.171. If your GPS is a TSO-c145/c146 unit (WAAS/stand-alone RNAV), you don't need anything else and the above paragraph doesn't apply.

7. Unlike TSO-C129 avionics, which were certified as a supplement to other means of navigation, WAAS avionics are evaluated without reliance on other navigation systems. As such, installation of WAAS avionics does not require the aircraft to have other equipment appropriate to the route to be flown.

I believe the above paragraph also applies to airplanes with aircraft based augmentation systems (ABAS), where the GPS is augmented by the IRU(s). Finding out whether or not your FMS works this way is up to you.

I just found a PDF from Rockwell Collins that says the following:

The FMS-3000, FMS-4200, FMS/AMS-5000, FMS-6000, and FMS-6100, perform the normal function of stand-alone GNSS equipment when in stalled with GPS-4000().

From that, I don't think you're required to to do the VOR check, but I also don't think your POI/FSDO or the guy ramp checking you will care what I think, and you should either do the test or find out what they think.

As far as how 91.171 applies to other FMS systems like DME/DME/IRU setups, I'm just a dumb flight instructor so I have no idea. I'll let you know as soon as I'm flying behind one...

 

[2000Easyguy]

just do a dual check every 30 days, we do it every couple of weeks and note it in our log. not a big deal and you are covered.

Agreed, simple as that! ^^^