/I Equipment suffix for panel mount VFR GPS.

[201er]

Byron, if you could get away with flying RNAV/Direct with your VFR GPS, it would make everyone else who paid $10K+ look dumb for getting certified equipment. That's why it's not gonna happen any time soon.

[Cris]

You need to read the entire table.  /I falls under the heading "Area Navigation (RNAV)".  There is a good description of RNAV systems in the AIM 5-1-8 .  /I is not just "VOR/DME", it is an approved RNAV system that uses VOR/DME to establish virtual VOR's or waypoints.  Such a system is also referred to as rho/theta RNAV.  It creates the "virtual VOR's" or waypoints by defining them in terms of a radial and distance from a VOR, and an approved system then allows the CDI to be used to fly a radial from that waypoint.   Yes I stand corrected. Reviewing the AIM would indicate that the term VOR/DME is really only referring to a computer with vor/dme to make the cals like the kns 80

[jetdriven]

Quote: 201er

Byron, if you could get away with flying RNAV/Direct with your VFR GPS, it would make everyone else who paid $10K+ look dumb for getting certified equipment. That's why it's not gonna happen any time soon.

[Jerry 5TJ]

A bit of an aside to this thread is -- enroute accuracy and ATC expectation.  

I have noticed that in the past few years ATC, at least in dense areas like Los Angeles or Phoenix, will call you if you begin to move even half a mile off an airway centerline.   Their expectation seems to be that we're all motoring along with enroute GPS accuracy and not just following the wandering VOR needle. 

My "legal" navaid is the  VOR in the panel of the "C" but the de facto navaid is really the Garmin Aera on the yoke.   It tells me if  I'm 1 degree off heading minutes before the VOR needle edges off the center dot...

 

 

[kris_adams]

Quote: gregwatts

Interesting Greg. So, when it does that is it momentary or does one unit arrive at the fix before the other or does the distance narrow between them as you get closer to the fix? If it is momentary, I'm curious how long does that discrepancy last; like is it less than 5 seconds, a minute, longer? Are you able to verify which one is correct with a RNAV unit or third GPS?

 

 

As I descend and get closer to the airport.......the gap closes. I believe that the 696 measuresthe distance from the airport to the unit....whereas the 430 measures from the airport to a point on the ground over which I am flying. The discrepancy only exists when the fix is an airport. A geometry thing.....I guess

[WardHolbrook]

Quote: xftrplt

Byron,

Since you elected to try your case in moot court, I'll offer an opinion:

Your logic may be correct, but you weren't /I for reasons expressed above. 

You may try to defend your position to the Feds, but

listen to your copilot, or, as they say, your hearing will improve at the hearing.

(Of course, there's no problem...until there's a problem.)

[bnicolette]

Byron............did you fill out a NASA report yet?  

I don't think it's a huge "foul".  It's not as if you were flying in some international RVSM RNP airspace or doing a RNAV1 arrival.  More of a "fauz pas".

[jetdriven]

I should put the LORAN back in to be legal.

[xftrplt]

Brett,

Your Francophone ancestors are surely spinning at your spelling faux pas. 

Dick

[bnicolette]

Quote: xftrplt

Brett,

Your Francophone ancestors are surely spinning at your spelling faux pas. 

Dick

[jlunseth]

Quote: Cris

 Yes I stand corrected. Reviewing the AIM would indicate that the term VOR/DME is really only referring to a computer with vor/dme to make the cals like the kns 80

[Becca]

Quote: jlunseth

 Sorry, didn't mean to "correct" anyone, just educate.  I got into this subject a couple of years ago because when I got my plane it had the original King nav system, "original" meaning that the KNS 80 could couple directly to the AP and HSI, and direct the flight.  I discovered that for GA, rho/theta or VOR/DME RNAV is an anacronism.  Plotting a course and creating a flight plan using it, was a real pain, because you had to put a scale on a chart and measure so many nm from a VOR, on such and such radial, and create all your own waypoints.  Filing was a pain too, because you had to file all those waypoints in the "ABC,104,21.5" formate, and half the time ATC no longer understood what that was.   When the KNS 80 came out there were tools available to make that easier, but they went away quickly partly because of GPS, and partly because the big users of rho/theta are the commercial airlines.  They have computer FMS's that autodial and ID VOR's as the plane flies along, and a database of waypoints bearing the same 5 alpha names we are familiar with using GPS.  The difference between what they use, and the KNS 80 available to us, aside from a huge difference in cost and weight, is that their systems are completely automated, where our KNS 80's were not, so we were stuck putting in one waypoint at a time by VOR, rad., dist.

A large part of the commercial fleet still has that system.  In the GA fleet, the cumbersome manual method represented by the KNS 80 has been largely replaced by GPS's with databases of waypoints so we don't have to do all that measuring and input.

Anyway, rho/theta RNAV has pretty much gone the way of LORAN, the nav aids are still there, and it is still possible to navigate by that means, but GPS is so much easier practically no one uses the system except the commercial fleet with their existing flight computer systems.

Easy enough to misread /I and similar designations if you don't know the background.  For that matter, if you don't know what RNP is or RVSM, easy enough to think you have those systems in a GA aircraft, when in fact practically no one does, they are beyond our means and/or need.

[jlunseth]

Yes ma'am, that would be correct.  Also, I would not rely on being able to make imaginative arguments at a hearing, if there were a hearing.  If you have ever read the decisions of the Admin. Judges, or the NTSB to whom their decisions are appealable, the process is a stacked deck, and "innocent until proven guilty" is not the standard.  If it were ever to get that far, you would need a very clear reason why their charges are just flat wrong, not an imaginative argument or possible alternative reading of the regs./AIM.

Sorry, Byron, if you lost the bet to Becca.  Will try to make it up to you somehow, us guys have to stick together.

[jetdriven]

If the FAA would ever get around to striking the word LORAN from the /I suffix and updating it properly to "enroute GPS" this would make all the sense in the world.