GRT without EXTERNAL GPS??

Is anyone flying or have experience with the GRT EFIS internal GPS, flight planning, autpilot, without a external GPS??

Anyone flying IFR using the GRT without an external GPS?

If coupled will it show GRT show the flight plan on the moving map??

Internal GPS is not IFR certified...

Hi!

Since I'm only flying my GRT EFIS with a Garmin 430, I can't answer you're main question, but as to your second one- the internal GPS from GRT is not intended to be used for IFR - it isn't certified. I may very well be wrong, but I don't think any of the commonly available Experiemtal EFIS's have approved internal GPS's.

Paul

Approved/certified GPS

I would like to know what the difference is between an approved GPS and a non/approved GPS. I hear a great deal about the the units certified for GA IFR usage but for the purpose of maintaining to the spirit of experimental usage does a GPS have to be "certified" or can a non certified unit be used in its place.

I just felt like stirring things up again.

pmercier said:

I would like to know what the difference is between an approved GPS and a non/approved GPS. I hear a great deal about the the units certified for GA IFR usage but for the purpose of maintaining to the spirit of experimental usage does a GPS have to be "certified" or can a non certified unit be used in its place.

I just felt like stirring things up again.

Click to expand...

One word: RAIM
RAIM is the abbreviation for receiver autonomous integrity monitoring, a technology developed to assess the integrity of GPS signals in a GPS receiver system. It is of special importance in safety-critical GPS applications. What this does is give the receiver itself the capability of VERIFYING the INTEGRITY of the GPS signals it's getting from the satellites.

A GPS is NOT a certified GPS that can be used for IFR flight unless it has RAIM capability, and correct me if I'm wrong, I don't believe any portable units have RAIM nor do any of the internal GPS options offered by various EFIS companies.

Experimental makes no difference, if it's not a RAIM enabled unit, it's not legal for IFR flight. I'm pretty sure "Experimental" doesn't apply to safety related issues that can affect the safety of other people in the system.

To be more accurate

To use a GPS for IFR enroute or Terminal approaches, the device must confirm to a specific TSO. This has nothing to do with whether you use TSO'd instruments or not. It has everything to do with the specific requirements of IFR flight and GPS operation.

It just so happens that RAIM is a part of the TSO specification.

Bottom line, if your GPS doesn't meet the TSO, you can't use it legally as the sole means of navigation for IFR. There are ways around this. If you are on Radar Vectors for example, you can use the GPS for situational awareness, etc and be on an IFR flight plan. Approaches get more complicated.

I also think that in order to file /G, the device needs to be certified for enroute and approach. Not 100% sure on this one.

aadamson said:

To use a GPS for IFR enroute or Terminal approaches, the device must confirm to a specific TSO. This has nothing to do with whether you use TSO'd instruments or not. It has everything to do with the specific requirements of IFR flight and GPS operation.

Click to expand...

Absolutely, that's what has to be applied to any of the equipment we use for IFR flight.

The thing is, it's real easy to disqualify a GPS unit using just the (lack of) RAIM criteria.
For GPS, if it's got RAIM, and it was designed for aviation use, then it's almost for sure to be IFR certified since it would be silly for a company to go to all the extra trouble to build in RAIM and NOT make sure it was TSO'd otherwise.

It it ain't got RAIM, it absolutely, positively, is NOT legal for IFR use since that's the most basic requirement for IFR flight.
As far as using it for situational awareness, that actually has nothing to do with IFR flight other than personal convenience because you're still operating under IFR legally by using other (IFR legal) equipment.

Raim

I guess I should read the TSO, but what I don't really understand is if the 430 gives you a RAIM alert, and that is your primary navigation system, what are you supposed to do? Just know that any data from the GPS is not accurate? Not accept any changes in heading? Ask ATC to allow you to hold for a while before flying the approach?

Also, couldn't you just get some RAIM prediction software running on your PDA and fly with any old GPS? You've got RAIM alerts now, right?

rv8ch said:

I guess I should read the TSO, but what I don't really understand is if the 430 gives you a RAIM alert, and that is your primary navigation system, what are you supposed to do? Just know that any data from the GPS is not accurate? Not accept any changes in heading? Ask ATC to allow you to hold for a while before flying the approach?

Click to expand...

You'd do the same thing as if you were on a VOR radial somewhere, and the little "Off" flag on the CDI pops up...

TSO'ed

Ironflight said:

Hi!
..........the internal GPS from GRT is not intended to be used for IFR - it isn't certified. I may very well be wrong, but I don't think any of the commonly available Experiemtal EFIS's have approved internal GPS's. Paul

Click to expand...

I agree you are correct; there is already some hellacious threads on this. Bottom line is if you want to GO IFR using a GPS navigation for any phase of an IFR flight, you must have an GPS TSO'ed for IFR ops and installed accordingly, period end-O-story. That means an external (from EFIS) panel mounted GPS. Very simple. If you want to play you got to pay. If you want to go IFR and use a GPS buy an approved IFR GPS unit and install it per the TSO. No worries, done deal and no questions. VFR? It does not matter and GRT's internal GPS should work fine for that use. George

Systems

rv8ch said:

I guess I should read the TSO, but what I don't really understand is if the 430 gives you a RAIM alert, and that is your primary navigation system, what are you supposed to do? Just know that any data from the GPS is not accurate? Not accept any changes in heading? Ask ATC to allow you to hold for a while before flying the approach?

Also, couldn't you just get some RAIM prediction software running on your PDA and fly with any old GPS? You've got RAIM alerts now, right?

Click to expand...

I actually think that if you read the regs, that GPS is *NOT* considered primary. In fact, there is some that believe that even with an approved and certified GPS, that you'd still need "ground based" navigation to be technically legal...

Ifr Gps

gmcjetpilot said:

If you want to go IFR and use a GPS buy an approved IFR GPS unit and install it per the TSO.

Click to expand...

Anyone know of a list of IFR GPS units?

All our club's pipers have either the 430 or the 530, but the only feature they have that I use is the radio! I prefer my 196, so it would be great to have a very cheap, but IFR approved GPS.

rv8ch said:

Anyone know of a list of IFR GPS units?

All our club's pipers have either the 430 or the 530, but the only feature they have that I use is the radio! I prefer my 196, so it would be great to have a very cheap, but IFR approved GPS.

Click to expand...

All IFR GPS's that I know of, are panel mounts. And then my Garmin 296 hand-held has higher screen resolution and more colors, than does the panel mounted 430/530.

Plus, most IFR panel mounts are not yet WAAS ready, as so many hand-helds already are.

L.Adamson

Keeping IFR GPS updated

One consideration for using an IFR GPS that I haven't seen anyone talking about is keeping the database current. I don't know if there is a LEGAL requirement to have a current database to fly IFR based on GPS data. I would think however that it would be CRITICAL to ensure that you have a current database. I know for a fact that is the LAS area, several fixes were moved this year on the STARs and SIDs. It could be at least embarrassing or potentially even worse to be depending on outdated data.

Considering the subscription fees to Garmin to maintain a current database vs GRTs free government based database, a reasonable alternative to a pricey IFR GPS would be to use a VOR for IFR legality and a noncertified GPS for SA.

Database

You don't have to keep the database current.... however, you do have to verify that any waypoint (and most assuredly the approach ones) in your current database is accurate. So you can tell, it's much easier just to keep the database current.

As for cheap ones just to have to meet the regulation... Don't think you'll find any. Well, that's not totally true, you can find the King KLN-89B (one of my favorites btw) for pretty cheap, used and in surplus. But it's just a GPS. 90's in some configurations are also certified I think. And there are some units that are certified for enroute, but not approach.

There was a WAAS, Certified, Module from freeflightsystems, but I don't know what happened to it nor do I know, other than with the Chelton, what it required for UI.

rv8ch said:

...it would be great to have a very cheap, but IFR approved GPS.

Click to expand...

In the current climate, I think you'll find that those two criteria are gonna be mutually exclusive...
Would be nice, though.

Planning with GRT GPS

Can you plan a flight with the GRT internal GPS (VFR) using several way points?

You Can Flight Plan On A GRT

Yes. I am flying a dual screen GRT with an internal GPS and it is very ease to load and save flight plans. All saved waypoints can be accessed. Too many features to mention here. You can go to their site and get the skinny. The system works very nicely. You can also install a panel mount IFR certified unit and display its information on the GRT.

Roger Ping
RV-9

About $3,500 for IFR GPS set up.

rv8ch said:

Anyone know of a list of IFR GPS units?

All our club's pipers have either the 430 or the 530, but the only feature they have that I use is the radio! I prefer my 196, so it would be great to have a very cheap, but IFR approved GPS.

Click to expand...

Here is a partial list of the cheapest IFR GPS I could find from about $1,900 to $3,000:

http://www.avionix.com/gps.html
http://www.avionix.com/Avionics Buyers Guide.pdf

You have to filter alittle, but this a partial list of "cheap" IFR GPS, both approach and enroute that I could find for sale:

UPS "AT" GX-50 $2,500
UPS GX-55R $2000; no approach/enroute-term only
UPS GX-60/COM $3,000
UPS GX-65/COM $2,000; no approach/enroute-term only
Honeywell Bendix/King KLN-89B $2,200
Honeywell Bendix/King KLN-90B $2,500
Honeywell Bendix/King KLN-94 $4,700
GARMIN GPS-155 TSO $2,000
GARMIN GPS-155XL TSO $2,400
GNC-300XLTSO$2,900 (IFR GPS Enroute/Appch/COM)
GNC-300 TSO $2,300 (same as above but XL has better LCD display)
II MORROW 2001GPS IFR $1,900 (lowest priced Enroute/Appch IFR GPS)
TRIMBLE TNL-2000 APPROACH "Plus"
NORTHSTAR M-3 APPROACH $1,900

The above prices are all Reconditioned and do not included installation, such as the NAV indicator (head) and/or the annunciator panel which are required (I think). An annunciator panel is about $500, and a NAV head is about $1,000-$1,300. So a "Cheap" IFR GPS set up would be roughly $3,500-$4,500. I am sure this stuff is available used on eBay for the same or less. A quick check found King 89B/90B's for less than $1000, Mid continent GPS head $200, and a few annunciator panels. I am guessing with some bargain hunting you can get under $2,000.

The Apollo GX-60 or the Garmin GNC-300/300XL seem like good values for a full IFR GPS with COM. The GX-60 GPS has a COM like that of SL-40 (ie listen to 2 Freqs simultaneously). Also at $3,000 the Garmin has COM and MAP for the same price. If you don't want Com the Apollo GX-50 or Garmin GPS-155/150XL look like good buys to me at $2,000-$2,500.

That is quite a bit cheaper than the Garmin GNC-430 ($7,500) or GNS-430 for about $9,000. However the GNS-430 has a Com and VOR/LOC/GS receiver. I don't think you need a NAV head for GPS NAV with the GNC-430, but if you want ILS approach capability, you need the NAV head with GS. The bigger screen 480/530 go up to over $13,000! Ouch!

(NO guarantee above data or prices are accurate, but I gave it a shot>use at your own risk.)

G

Very good data George!

It's jus too bad that we'll never be able to enjoy the economies of scale in avionics that all other electronics consumers see...if Garmin could build and sell millions of 430's, we'd be paying a whole lot less for them!

A couple of additional comments for folks. Annunciators are no longer required per se - if the unit has built-in annunciation, and it is in the pilot's "field of vision", you can get by without them. And the need for a remote display (CDI head), is one of the nice things that you cna fullfill with the GRT EFIS - it serves as the display, so that's one less thing you have to buy.

When I did my trade studies on instrument panels, I priced a dual-screen EFIS versus a six-pack with an HSI (I wanted to compare apples to apples in terms of situational awareness capability). Due primarily to the price of HSI's, I found that the cost difference was essentialy nil. When you add up all the things that the GRT EFIS replaces (Gyros, vacumn pumps and systems, CDI heads, fault detection systesm, etc), you find that the price really is a bargain!

Paul

rv8ch said:

I don't really understand is if the 430 gives you a RAIM alert, and that is your primary navigation system, what are you supposed to do? Just know that any data from the GPS is not accurate? Not accept any changes in heading? Ask ATC to allow you to hold for a while before flying the approach?

Click to expand...

It's been a while since I've flown anything with IFR certified GPS but if I remember correctly, RAIM only comes into play during approaches. I believe it went something like this. You load a GPS approach into the current flight plan. As you near the FAF you should get a green RAIM light telling you RAIM is working and the signal is good for shooting the approach. No green, no approach; go directly to missed. If you get the green and start down the approach and then get a RAIM failure warning, the approach is automatically abandoned by the GPS which cycles to the published missed approach fix. After going missed you should be able to go back out and give the approach another go and see if the signal gets better the second time around. So from what I understand A GPS experiencing a RAIM failure is still accurate enough to get you to enroute fixes safely. It's just not accurate enough to get you down a narrow approach path.

raim

one feature that all the ifr-approved gps's with which i am familiar had is "raim prediction". to use this feature requires that you enter your route and have good position info (gps must have "found" itself). then, you can get the unit to predict whether or not you will have good geometries for the approach at your eta (uses the almanac data to project the positions of satellites in view for your destination, iirc, from 15 minutes before your eta till 15 minutes after your eta.) even the old kln89b i used to fly had this feature. of course, many users don't bother with entering a flightplan, so they can't take advantage of this feature. (also, it may take some digging in the manual to figure out how to do it.) but i think it's pretty cool.