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#1
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"Fred E. Pate" wrote in message ... Ron Natalie wrote: The regulations just say that if you are going to use GPS that your alternate requirements have to be met without using GPS. They're figuring satellite geometry failure (GPS system) not the reliablity of the box installed. Which is more likely though? I guess, by induction or extrapolation or whatever, that the FAA figures ATC can handle one guy having a bad day at a time (if his GPS/NAV box fails) and not half the airplanes all at once (widespread GPS jamming or satellite system failure). Depends on who made your equipment :-) But the issue is, that they were concerned about GPS signal reliability NOT the reliability of any single manufacturer's unit by this requirement. |
#2
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"Richard" wrote in message t... Probably this has been answered in this forum previously, but I can't find it. Sorry. I recently got into a friendly discussion with a knowledgable CFII who said a Garmin 430 could not be legally used as "sole means of navigation". Looking back, I think what he means is that "GPS" (even IFR certified units) can not be used as sole means. Since the Garmin 430 contains not only TSO'd GPS but also VOR, LOC, GS, etc., my position is that this unit (without any other navigation equipment on board) is legal as a "stand alone" for use en route, terminal, and approach . (I know charts are still necessary.) Please advise. The pressure altitude input and operator input baro correction, such as the new UPSAT unit, will be a requirement for "sole means". John P. Tarver, MS/PE |
#3
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GPS: TSO C129a, Class A1 (en route, terminal, and approach) Yeah, your guess that he was referring to just the GPS portion is correct. I've read about this "sole source" stuff in a number of places. A non-WAAS reciever, as the 430s currently are, cannot be used as "sole source" for anything except GPS approaches. Say, for instance, that you're cleared along an airway. If so, you have to have a working VOR reciever available and the VORs that define that airway have to be operational (its in AIM 1-1-21). But, as you say, the 430 has a VOR reciever, so you're okay (the 400, however, doesn't; it is just a GPS). Maybe that's why airways aren't in the 430's database. Now, if you don't intend on ever using VORs, you don't need a VOR reciever, right? At least not outside of Class B airspace. In fact where does it say that you need anything more than a wet compass and a clock? And, if you can be legal with just a compass and a clock, certainly you can't become illegal if you add an IFR GPS, right? So what the hell does it mean, this "sole source" thing anyway? Peter |
#4
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"Fred E. Pate" wrote in message ... GPS: TSO C129a, Class A1 (en route, terminal, and approach) Yeah, your guess that he was referring to just the GPS portion is correct. I've read about this "sole source" stuff in a number of places. A non-WAAS reciever, as the 430s currently are, cannot be used as "sole source" for anything except GPS approaches. No, a 430 does not have accurate enough an altitude datum to be sole means. Altitude is the first portion of WAAS to turn out to be a bust. |
#5
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Tarver Engineering wrote:
"Fred E. Pate" wrote in message ... GPS: TSO C129a, Class A1 (en route, terminal, and approach) Yeah, your guess that he was referring to just the GPS portion is correct. I've read about this "sole source" stuff in a number of places. A non-WAAS reciever, as the 430s currently are, cannot be used as "sole source" for anything except GPS approaches. No, a 430 does not have accurate enough an altitude datum to be sole means. Altitude is the first portion of WAAS to turn out to be a bust. Well, I don't think "sole source" is that restrictive. A VOR reciever is approved as a "sole source" of navigation. You still need an altimeter. "Sole source" just refers to horizontal navigation. All GPS approaches are currently non-precision: no vertical guidance. |
#6
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"Fred E. Pate" wrote in message ... Tarver Engineering wrote: "Fred E. Pate" wrote in message ... GPS: TSO C129a, Class A1 (en route, terminal, and approach) Yeah, your guess that he was referring to just the GPS portion is correct. I've read about this "sole source" stuff in a number of places. A non-WAAS reciever, as the 430s currently are, cannot be used as "sole source" for anything except GPS approaches. No, a 430 does not have accurate enough an altitude datum to be sole means. Altitude is the first portion of WAAS to turn out to be a bust. Well, I don't think "sole source" is that restrictive. A VOR reciever is approved as a "sole source" of navigation. You still need an altimeter. "Sole source" just refers to horizontal navigation. All GPS approaches are currently non-precision: no vertical guidance. I do not believe "sole source" is regulatory. You may as well use the term "eanie beanie". |
#7
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Tarver Engineering wrote:
I do not believe "sole source" is regulatory. You may as well use the term "eanie beanie". Sounds good to me. "Not approved for eanie-beanie navigation without an upgrade." |
#8
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Thanks to everyone who contributed to this discussion. Special thanks to
those who actually answered my question! "Richard" wrote in message t... Probably this has been answered in this forum previously, but I can't find it. Sorry. I recently got into a friendly discussion with a knowledgable CFII who said a Garmin 430 could not be legally used as "sole means of navigation". Looking back, I think what he means is that "GPS" (even IFR certified units) can not be used as sole means. Since the Garmin 430 contains not only TSO'd GPS but also VOR, LOC, GS, etc., my position is that this unit (without any other navigation equipment on board) is legal as a "stand alone" for use en route, terminal, and approach . (I know charts are still necessary.) Please advise. The following came off the Garmin web site: ****************** GPS: TSO C129a, Class A1 (en route, terminal, and approach) VOR: TSO C40c LOC: TSO C36e GS: TSO C34e VHF COM: TSO C37d, Class 4 and 6 (transmit) and TSO C38d, Class C and E (receiver) The GNS 430 is the most versatile panel-mounted product GARMIN has produced to date. It combines GPS navigation, VHF communication, and moving map graphics on a big color display. This "all in one box" 12-channel unit offers IFR GPS, ILS, VOR, LOC and glideslope capability in a single, space-saving package ************************** |
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