comments from gps users?

[buzzer]

JediNein,
Hmm...Perhaps an inexpensive, no map, used IFR GPS installed/tested would allow you to use your fantastic VFR GPS as your "main" companion during IFR flights on a budget.

 

[sstearns2]

Hello,

You can get a factory reman King KLN-89B for about $1700. There may be an IFR GPS that will just plug into your current tray.

As far as using a VFR GPS in actual IFR.... I have a lot more faith in the GPS signal than any VOR signal. I've seen VOR needles wander all over the place, but I've never seen a GPS needle so much as quiver. The question is whether it's worth risking your tickets or not.

Also, someone previously talked about RAIM. I don't belive RAIM monitors the signal at all, it just looks into the future and makes sure you will have acceptable satalite geometry along your route. I beleive that there are enough GPS satalites over the US now that it is never a problem. I've never seen less than 7 or 8 satalites available on my handheld. The minimum is 4 to get a solution and they can't be in a straight row across the sky. (The geometric accuracy of the signal is directly related to the area enclosed by connecting the satalites together, the larger the area the better the solution.) Has anyone see less than 4 anywhere?? Also most GPS units actually monitor more that the minimum number of satalites and constantly cross check between them, so the unit will quickly figure out if it's getting a bad signal. Also the military monitors all the satalites all the time.

Scott

 

[JediNein]

Howdy!

Yes, I've seen an IFR GPS disagree with a VFR LORAN, a handheld GPS, and the view out the window. The IFR GPS was the most correct, and the view out the window was the absolute correct.

I've watched another IFR capable GPS, VFR installation, quit with database and other errors while the VOR continued working.

I can tell when a student is using GPS navigation versus the VOR because the VOR scallops on a certain approach. Lotsa fun.

I've watched a student fly a GPS approach in actual to see the "RAIM not available" message just before the FAF. It gave the student a much needed wake-up call. If he would have checked the GPS NOTAMS, he would have flown the VOR approach instead.

I watched another GPS unit, IFR installation, just not certified, give an "estimated position" when it lost signal reception from all but two satellites. The NDB was the only signal available in that particular situation. There was a lot of rock between us and the other satellites.

I've also seen all sorts of wierd and unusual error messages from the units when installed incorrectly. Usually it is a missing ground wire connection, or two flip-flopped. The worst occur when the shop forgets to reset the sensitivity, squelch, and OBS setting.

As for the eBay sale on both the KLN89B and Garmin 430, I know the manufacturers tend to yank dealership authorizations for selling new units there, used, well, good luck. Buyer beware. It will be interesting to see how much those go for. The completed sales on the GARMIN 430s show about $5200 through $5900. Not much more money and one gets a new unit; $960 through 1800 on the KLN series. Still much cheaper than a couple of pilot certificates.

Fly SAFE!
Jedi Nein

 

[Timebuilder]

I submit that there is a difference in many units between a "VFR only" unit, and a unit which is certified for IFR use, but has an expired database. I would only use the VFR unit as an adjunct to the VOR nav system. I would put significantly more faith in an IFR unit which is not currently "legal" due to the data, particularly for enroute use above obstructions, such as above 14,500 MSL. I would not shoot an approach GPS only with expired data, but I would have it up and running to augment the VOR indication.

Using the moving map function, I have never been mislead by a GPS because of the course line being too wide in terms of pixels or miles. I just change scales to have the map represent a smaller area.

 

[aggiepilot87]

GPS is more reliable than VOR and LORAN at any given point in the US. A particular GPS reciever may be more or less reliable than a particular VOR or LORAN receiver, though.

Expense and one's ability to absorb it is *relative*. I'm glad Jedi can buy Garmin 430's off eBay and have them installed and kept current in her(?) plane. I can't.

But I can buy *enroute charts that are current* and use my $89 Garmin eTrek GPS to give me a direct heading. Where in this assumption did I say I wouldn't be checking for obsticles, keeping track of "primary" navaids, assuring alternate airport availability, or keeping good situational awareness?

For those folks not flying >$1 mil aircraft, I think filing /a or whatever is appropriate (minus the handheld), *then* asking for direct by own nav or "suggesting" a direct vector, is totally acceptable and legal. Therefore the risk of loosing a certificate is not a factor.

If they ask how you determined your direct nav, CNAV sounds good to me... maybe a very sharp pencil and a good straight edge!? same difference really.

 

[Timebuilder]

How about an old Garmin without any kind of map, or a similar Trimble product? The '$2mil plus' planes that I see on the ramp would LOVE to have a Garmin 430 in their panels. The best unit among all those planes is a Universal FMS. That, too has no map. Cost of the plane doesn't mean a lot in terms of the avionics.

Here's a anecdote on "direct" requests.
I had flown out to Ohio for a guy I know in his Cherokee Six, a nice one with older avionics. For the flight back from OSU airport, I filed my first fix as direct to the Appleton VOR, and then V 12 to go home to Reading. I used the /A for the flight plan suffix.

When I called for my clearance, the OSU ground controller questioned the "direct Appleton", asked if I was GPS or Loran equipped, and said that the Columbus tower would want to know how I would get to the VOR. Believe it or not, I had to explain to him that I was going to tune in the VOR, center the needle with a "TO" indication, and fly "direct" to the VOR. Columbus didn't question my ability to get there when I was told to contact them for departure, and the flight was uneventful. Except, that is for the strong tailwind at 11,000 feet that let me get the Cherokee up to 200 knots of groundspeed!

 

[BigFlyr]

My 2 cents for what its worth... As pilots, we always have to consider "what is safe" and "what is legal". With a VFR GPS you cannot file (not legal) as a /G. However, as long as you can backup your position by conventional means (VOR-NDB) you can request direct routing using your GPS. Its done all the time and everyday by 121 as well as 135 and 91 operators. Then again, if there's a Fed on board... ???

 

[Timebuilder]

If there's a Fed on board?

On Sunday, when I was coming back from Boca, I overheard an exchange bewtween Washington Center and a government aircraft used by, shall we say, a 'high government administrator'. The tail number has an "N" and one other digit.....

Center asked the aircraft to change its altitude, and the FO, a young sounding gentleman, seemed a little surprised by the request. You should have head the care and enunciation that the Center controller used to explain that the new altitude would be consistent with the new direction of flight.

It was as if the passenger who is typically on board the plane had been expected to be listening in.

 

[ksu_aviator]

Buzzer, I guess what I was trying to say is don't go IFR with a VFR GPS using only the GPS. I don't know what ATC has, but I do know if they ask you if you are RNAV its because they are questioning what they are seeing infront of them versus what you are telling them. They do know if you filed /a or /g.

 

[JediNein]

High ranking officials

Even highly ranking government officials have to make mistakes in order to learn too. It's possible she was sitting Captain.