comfortcat

comfortcat

Well Known Member
Friend
So, to continue my discussion of a GPS Only ship, has anyone looked at these folks:

http://www.accord-technology.com/index.html

and would a NexNav Min or Max allow me to have an IFR certified GPS only aircraft?

My panel will be a Dynon Skyview, two Dynon Comm radios, a Dynon Transponder and one of these babies!

Maybe a MGL Xtreme for backup?

Yea!!!!

Dkb
 
I looked at their web site. It looks to me like they are selling gps receivers which meet certain specs for receivers. But a complete ifr system combines the receiver with a database, has software which leads you thru approaches, etc.

GRT has promised an ifr gps by next spring using this or a similar receiver. I presume they will somehow use their efis to do the system integration of the gps position with an ifr database. I don't know how they plan to do database updates.
 
For many folks (myself included) in order meet the ADS-B out position requirments, and to take full advantage of ADS-B in, will need to install a certified postion source like the MiniMax or the Freeflight 1201. These options will be more affordable than installing a 430/650 GPS solution (which currently do not meet the ADS-B out requirment but should be software upgradeable to the new spec).
 
Last edited:
comfortcat said:
So, to continue my discussion of a GPS Only ship, has anyone looked at these folks:

http://www.accord-technology.com/index.html

and would a NexNav Min or Max allow me to have an IFR certified GPS only aircraft?

My panel will be a Dynon Skyview, two Dynon Comm radios, a Dynon Transponder and one of these babies!

Maybe a MGL Xtreme for backup?

Yea!!!!

Dkb
Click to expand...

Yesterday flying an IFR GPS approach into Apple Valley, I had my IFR Approach Certified GPS give me a RAIM error. Cannot do an IFR approach with a RAIM error.

What will you do when your GPS is jammed or unusable while flying? Yes it does not happen very often but it does happen.

There is an FAA NOTAM for GPS outage centered around Oceanside from October 20 to October 26. How are you going to fly a GPS approach during this planned outage?


!GPS 10/058 (KZLA A2480/12) ZLA NAV GPS IS UNRELIABLE AND MAY BE UNAVAILABLE WITHIN A RADIUS OF 467NM AND CENTERED AT 325447N/1061206W OR THE LOCATION ALSO KNOWN AS THE TRUTH OR CONCEQUENCES, NM VOR /TCS/ 112 RADIAL AT 58 NM AT FL400 AND ABOVE. DECREASING IN AREA WITH A DECREASE IN ALTITUDE TO A RADIUS OF 419NM AT FL250, A RADIUS OF 341NM AT 10000 FT MSL, A RADIUS OF 344NM AT 4000FT AGL, AND A RADIUS OF 302NM AT 50 FT AGL. WEF 1210251900-1210252300


!GPS 10/057 (KZLA A2479/12) ZLA NAV GPS IS UNRELIABLE AND MAY BE UNAVAILABLE WITHIN A RADIUS OF 467NM AND CENTERED AT 325447N/1061206W OR THE LOCATION ALSO KNOWN AS THE TRUTH OR CONCEQUENCES, NM VOR /TCS/ 112 RADIAL AT 58 NM AT FL400 AND ABOVE. DECREASING IN AREA WITH A DECREASE IN ALTITUDE TO A RADIUS OF 419NM AT FL250, A RADIUS OF 341NM AT 10000 FT MSL, A RADIUS OF 344NM AT 4000FT AGL, AND A RADIUS OF 302NM AT 50 FT AGL. WEF 1210241900-1210242300


!GPS 10/037 (KZLA A2448/12) ZLA NAV GPS IS UNRELIABLE AND MAY BE UNAVAILABLE WITHIN A RADIUS OF 205 NM AND CENTERED AT N33 00 00 W118 20 00 OR THE LOCATION ALSO KNOWN AS OCEANSIDE VOR (OCN) 253 RADIAL AT 48 NM AT FL400 AND ABOVE; DECREASING IN AREA WITH A DECREASE IN ALTITUDE TO A RADIUS OF 170NM AT FL250; A RADIUS OF 150NM AT 10,000FT MSL; A RADIUS OF 140NM AT 4,000FT AGL; AND A RADIUS OF 100NM AT 50FT AGL 1300-1500 DLY WEF 1210171300-1210241500
 
In Canada, a GPS only airplane isn't legal for IFR. If you plan any trips up here, you'd be VFR only.
 
Walt said:
For many folks (myself included) in order meet the ADS-B out position requirments, and to take full advantage of ADS-B in, will need to install a certified postion source like the MiniMax or the Freeflight 1201. These options will be more affordable than installing a 430/650 GPS solution (which currently do not meet the ADS-B out requirment but should be software upgradeable to the new spec).
Click to expand...

Upgradeable now, apparently...

http://www.vansairforce.com/community/showthread.php?t=92224
 
bkthomps said:
i don't know what that implies, but i have loss radar coverage plenty of times before to know that I do not and will not rely on it. radar vectors to final is a luxury when it works, sure.
Click to expand...

So now that's a two-failure scenario...lost GPS AND lost RADAR. How about I one-up you...VORs can and do go OTS regularly. So now you have no GPS, no RADAR and no VOR.

Going to add ADF to your panel "just in case"? :)

Around here, vectors to final is all I have ever gotten unless I specifically requested the full procedure.
 
Flying Scotsman said:
So now that's a two-failure scenario...lost GPS AND lost RADAR. How about I one-up you...VORs can and do go OTS regularly. So now you have no GPS, no RADAR and no VOR.

Going to add ADF to your panel "just in case"? :)

Around here, vectors to final is all I have ever gotten unless I specifically requested the full procedure.
Click to expand...

i'm with the flying scotsman on this. not to mention all of the a/c i see who routinely file /A over VORs that haven't been turned on for several years. :rolleyes:

i think there is a give and take here. in flat country, it's a little silly to plan for lost radar, unless you're down low. different ballgame in the mountains, im sure.
 
NickAir said:
On the West Coast States radar coverage is an issue at times.
Click to expand...

...and in northern MN, WI, and Michigan - especially the UP, as well as in much of ND and SD.

I've heard "Radar contact lost" more than I've had a VOR flag or GPS RAIM error; I agree that relying on radar service as a means of navigation is not great idea.
 
Last edited:
Flying Scotsman said:
So now that's a two-failure scenario...lost GPS AND lost RADAR. How about I one-up you...VORs can and do go OTS regularly. So now you have no GPS, no RADAR and no VOR.

Going to add ADF to your panel "just in case"? :)

Around here, vectors to final is all I have ever gotten unless I specifically requested the full procedure.
Click to expand...

no, radar service can come in and out, especially if you go lower, say, an approach- which is what matters the most when you've lost your primary navigation

ILS/LOC is completely separate from VOR's yet use the same equipment on your plane, why not have at least LOC functionality?
 
ChiefPilot said:
...and in northern MN, WI, and Michigan - especially the UP, as well as in much of ND and SD.

I've heard "Radar service terminated" more than I've had a VOR flag or GPS RAIM error; I agree that relying on radar service as a means of navigation is not great idea.
Click to expand...

radar service terminated just means "i dont want to work you anymore."

"radar contact lost" is a different ballgame.


generally speaking, if you can get up out of the weeds in the midwest, somebody will be able to see you. this is only going to get better with ads-b (fingers crossed)
 
Echo Tango said:
This is only going to get better with ads-b (fingers crossed)
Click to expand...

Well, I guess I'm more confused now then ever. I'm also building a "GPS only" navigation ship (no nav radios). But it looks like a lot of you guys have reservation about going that route. I would think that if the FAA is switching to GPS based technology (ADS-B) for separation and basically getting away from radar, that it would be rock solid enough for navigation purposes. Am I missing something here? :confused:
 
Mark33 said:
Well, I guess I'm more confused now then ever. I'm also building a "GPS only" navigation ship (no nav radios). But it looks like a lot of you guys have reservation about going that route. I would think that if the FAA is switching to GPS based technology (ADS-B) for separation and basically getting away from radar, that it would be rock solid enough for navigation purposes. Am I missing something here? :confused:
Click to expand...

those of us who work with technology or have first hand experience with GPS systems and how they work (and fail), will probably be the strongest advocates of alternatives for IMC or night flying

simply put, relying on radar coverage from ATC by some in this thread show a clear lack of understanding of what IFR is and what is required. There are plenty of IFR routes that will be out of radio/radar coverage range, there is also a lot of approaches in valleys and low areas that are not covered by radar, you can't always choose your approach especially if you have to make an emergency landing
 
Echo Tango said:
radar service terminated just means "i dont want to work you anymore."

"radar contact lost" is a different ballgame.


generally speaking, if you can get up out of the weeds in the midwest, somebody will be able to see you. this is only going to get better with ads-b (fingers crossed)
Click to expand...

My bad - it was "radar contact lost". You don't get to decide not to work me anymore when I'm on an IFR plan :)

Is 5000 ft "out of the weeds"? Because I've been at 5K and been out of radar contact when approaching LaCrosse WI...
 
Last edited:
Now you guys are talking about RADAR coverage failures, which again, for the OP and his situation, would be a two-fault scenario (whether that's a reasonable scenario or not may depend upon his mission, including time, terrain and weather).

The FIRST failure would be some sort of GPS issue which prevented GPS from being used as either primary en route nav or for an IAP, which would then, for the OP's configuration cause him to switch to his backup/secondary navigation mode, which in his case would be RADAR vectors to a position from which he could make a visual approach (having no VOR/LOC/GS capability).

The SECOND failure would be a RADAR outage when not expected by ATC (not, I submit, a "normal" loss of return because of whatever conditions exist in the local area, but a station going down or some other true failure).

(BTW, FWIW, I have a 430W and Dynon SV1000, so yes, I have both GPS and a VOR/LOC/GS :) ).
 
Backto the message

OK, lots of good advice here. Some OWT and some Chicken Little.

Yes, GPS can go out.
When you get RAIM errors, does that mean three satellites fell out of the sky?
Yes, VOR can go OTS or TU
Yes, the ILS can fail.
Even the Filmore VOR can burn to the ground.

BUT

The issue here is What does a modern plane need for safe IFR flight?
Since you can get a VOR/ILS/MarkerBeacon unit for about $2000 that fits in one 3 1/8 hole, the real question is:

Is it safer to fly GPS only with appropriate backups than to get in the soup, have a hardware failure and then try to shoot an ILS approach that you have only done occasionally in practice over two years ago to minimums?

Yes, you can have dual everything, and still have an engine failure in IMC. At least right now, we do not have dual engines in the Van's line.

So how about it guys:

Two comms
One Certified IFR GPS
One backup GPS (built into the EFIS)
Transponder
ADF

Sound good? :rolleyes:

(Just kidding about the ADF)

Dkb
 
bkthomps said:
those of us who work with technology or have first hand experience with GPS systems and how they work (and fail), will probably be the strongest advocates of alternatives for IMC or night flying

simply put, relying on radar coverage from ATC by some in this thread show a clear lack of understanding of what IFR is and what is required. There are plenty of IFR routes that will be out of radio/radar coverage range, there is also a lot of approaches in valleys and low areas that are not covered by radar, you can't always choose your approach especially if you have to make an emergency landing
Click to expand...

I agree with your statement with regards to not relying on radar coverage for navigation in IFR conditions, approaches, etc., but in terms of GPS based navigation and ADS-B technology, as the O. P. was implying, there still seems to be quite a bit of concern from many people that it's not a good idea to rely solely on GPS based equipment for navigation. I understand the desire to have backup systems in place but at some point you run out of backup systems. Like I said in an earlier post, I'm building my ship with GPS navigation only, along with ADS-B (in and out). Although my current position source for the ADS-B "out" is not a "certified" unit (I'll be using my G3X), I'm anticipating the availability of a very small and cost effective "certified" GPS position source that that I'll be able to add on later. So, with the direction and the reliance on GPS based navigation equipment and technology is going, I hope that I'm making a wise decision to go GPS only and that my bird will be safe and reliable to fly anywhere in all kinds of weather. Although VOR's will be around for a long time to come, I can see the day when they'll all be decommissioned and that navigation, and ATC tracking and separation will all be GPS based. :)
 
comfortcat said:
So how about it guys:

Two comms
One Certified IFR GPS
One backup GPS (built into the EFIS)
Transponder
ADF

Sound good? :rolleyes:

(Just kidding about the ADF)
Click to expand...

There's still a lot of the world where an ADF would be required.

If I were building an IFR plane, I'd go with a GPS/Nav/Com and a secondary Nav/Com
 
Mark33 said:
Although VOR's will be around for a long time to come, I can see the day when they'll all be decommissioned and that navigation, and ATC tracking and separation will all be GPS based. :)
Click to expand...

Not sure I share your vision about ATC separation being GPS based. I can see GPS supplementing areas of weak RADAR coverage. But if we went to a solely GPS based system, a GPS failure would affect a much larger area than our current RADAR failures, making our sytem far less reliable.

We have hundreds of RADAR sites that currently overlap...so even a RADAR failure is limited to the disruption it could cause.

Interesting theory though....I have seen the FAA adopt crazier ideas.
 
well that's hte point of ADS-B... but since they don't trust GPS just yet, as they're afraid of these widespread outages, they are requiring you to keep the transponder anyways.. but 100 years from now when GPS proves to be a reliable technology, they will do away with transponders... maybe..
 
All this talk of multiple back-ups sure seems like way too much overkill to me. This is a homebuilt airplane not a corporate jet or an airliner. Having a handheld GPS as a back-up for use in the highly unlikely event that his primary quits seems like a good solution. Are you really that worried about dispatch reliability? If everything goes bad, get radar vectors, like you or somebody else said. Will you be able to get to your intended destination? Maybe not, might have to go to some big airport, but you have a problem - doesn't happen very often, maybe never. If so, go to the big airport and wait until the weather gets better. If you are using your experimental as a traveling machine that requires you to have to absolutely be there at a specific time, maybe you should think about buying an airline ticket. You won't have to worry about not getting home and having to spend another day or two in paradise waiting for the weather to improve because you've had an avionics snafu (which almost never happens - chances are, if it does happen, the weather will be VMC anyway....). Strickley GPS navigation is where we are all headed eventually. I don't see anything wrong with that. Navigation management is way simpler, and you don't clutter up your panel with useless (most of the time) avionics that you don't need. Everbody has their own opinion, you've asked, that's mine....
 
Radomir said:
well that's hte point of ADS-B... but since they don't trust GPS just yet, as they're afraid of these widespread outages, they are requiring you to keep the transponder anyways.. but 100 years from now when GPS proves to be a reliable technology, they will do away with transponders... maybe..
Click to expand...

Well correct me if I'm wrong, but the only real reason that a transponder is being used with ADS-B is so that your GPS position can ride piggyback on that transponder radio signal and then show up on the ATC's screen. So in essence, the transponder is only there to transport the GPS signal and your squawk code...there would really be no other way to get that information to ATC other than riding that transponder radio wave. Furthermore, the way I understand it, all ground based radar will eventually be decommissioned once ADS-B is fully implemented. So, once again, it looks like navigation, position, and separation will be GPS based (via ADS-B). So, I guess the question still remains, is it a wise decision to build your panel around new GPS technology or do we still really need old VOR based radios? I personally think that if ATC is transitioning to GPS based ADS-B for something that's as critical as separation and tracking, then I don't think navigation in our RV's will be a problem.
 
In the US, there are two ways to get your gps ADSB position to the ground. One way is via your mode S transponder. The other way is thru a transmitter on a nearby frequency refered to as UAT. Sorry I forget what that stands for. Dynon is selling a transponder based system. Navworx is selling a UAT system.
 
My two cents: This whole discussion is only part of the big picture of risk management. In the real world where dollars and panel space are limited, most of us have to make choices. A VOR? secondary electrical bus? back up attitude instruments? (this last one is #1 on my list). And what is the mission? I'd feel very comfortable flying IFR to my destination with only one nav source IF I had a solid gold VFR alternate that I could reach, safely, using just dead reckoning.
And I'd feel very uncomfortable flying with all the instruments I could cram onto the panel if my destination was below minimums and my alternate just barely forecast to meet alternate min's and I had legal minimum reserves of gas. As always a lot of the real risk management lies with the person behind the stick. No one wants to hear this but some of the best money spent is on gas, keeping IFR current.

I personally chose one GPSw (420), one VOR/ILS (SL30) but note in different boxes, so one failure would leave options. No secondary buss but independently battery powered backup efis (D6), portable gps and VOR.

No one has mentioned it, but for the budget minded a handheld transceiver that also has a VOR is a useable backup. I have the original Sporty's, it only shows VOR radials in digital form; but I've done VOR approaches under the hood with everything off but the D6 and the handheld, it can be done. Just keep the batteries fresh, and/or carry spares.
 
You must log in or register to reply here.