3 GPS Questions

Nick

Nick

Well-Known Member
Hi folks,
I've got three questions regarding GPS. I am using the Garmin 430 and have been for quite a while, but while answering a sheet of questions relating to GPS usage there is three that I cannot find anywhere:

1) How are Victor airways programmed into the unit? What if the airway has a dogleg?

2) 2. May ATC initiate a GPS-only approach?

3) Why is it considered good operating practice to know and file the Latitude/Longitude coordinates of your destination airport, particularly on long direct flights?

Thanks to anyone who can help me. Also, I found a good powerpoint presentation on GPS online from the Washington, DC FSDO. You can download it HERE .
 
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1) How are Victor airways programmed into the unit? What if the airway has a dogleg?

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When I use the 430 to fly airways, it's pretty simple. Use the flight plan function, and simply enter all of the intersections and NAVAIDS as waypoints. Once you get that done, it's just a matter of flying point to point! It seems like alot of work, but I can fly a 300 mile trip and only take an extra 2-3 minutes to gete all of the waypoints entered.

I will say that anytime I fly with the GPS, I keep a low enroute chart handy just to cross-check. It helps when you lose the GPS (RAIM) and need to switch to VHF navigation all of a sudden.

If you try to navigate Victor airways by simply entering the VOR stations as waypoints, you can very well be screwed if the courses chage, so the intersection method is alot easier.

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2) 2. May ATC initiate a GPS-only approach?


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Yes, as far as I know. If they can't, they have!!

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3) Why is it considered good operating practice to know and file the Latitude/Longitude coordinates of your destination airport, particularly on long direct flights?


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Not sure....maybe something to do with the center being able to enter it into the computer?

Even that answer doesn't make sense to me, because if you file /U (no GPS or DME), you don't have to enter a LAT/LONG. I've never done such a thing. The one thing that I do like to do (because the AIM says to do it) is ensure that I enter at least one waypoint in the airspace of each center that I'll be passing through.
 
1.) Best way to do it is program your route into the FPL page. Any doglegs in the airway, or airway changes will be taken care of as long as you enter defining points (VOR's, intersections, etc.) along that route. For a short flight, you can also put it into OBS mode, enter the VOR that the airway goes to/from and put the course of the airway in the OBS. This will create a pink line going to/from that fix. The airway number won't show up or anything like that, but it's accurate.

2.) I don't believe so. Filing /G doesn't necessarily mean the GPS has approach capability- just en route and terminal. Therefore, I don't see how ATC could initiate this type of approach.

3.) Because if you're flying a long trip (spanning several ARTCC's), the center you depart from might have no clue where your destination airport is. If they know that lat./long, you have a better chance of getting direct. At least thats what I've been told. I've been asked for coordinates on several occasions, flying long flights where I filed direct.
 
Thanks so far. Regarding #1, I always use the flight plan (FPL) method on cross country flights. However, don't you think there should be a way where you can just type:
ABC (VOR)
V123 (airway)
XYZ (VOR)

That way you wouldn't have to type out something like:
ABC
INTERSECTION
INTERSECTION
LMN
INTERSECTION
RST
INTERSECTION
INTERSECTION
INTERSECTION
XYZ

It would save type and reduce the chance of typos.
 
Should be, but unfortunately, there isn't. At least not yet...one would think Garmin could come up with a simple update to fix that.
 
I think you have to REQUEST a GPS approach. I believe ATC assigns whatever approach is in use at the dest airport. I know here at ORL, that info is on the ATIS i.e. "ILS Runway 7 in use" or "LOC/BC Runway 25 in use." If it's a non-precision approach airport, they may ask which approach you would prefer.
 
you don't need to enter in every intersection along your route. just put the starting point and ending point. the victor airway is defined by those two points. it's usually only a couple of degress off from your VOR indications. i only used intermediate intersections if there was a change in the MEA or something of that nature. you SHOULD be using your VOR recievers as a back up in case you lose RAIM. if your a/c has dual VOR's you can tune in the cross radials to define intersections if you want. if your making a dog leg onto another airway, just put in starting point on V1,ending fix on V1, then ending fix on V2 and it paints a pretty picture. gosh i love that thing!
 
<hijack>

Hey, I wonder if this guy's a Mooney pilot.
smile.gif


</hijack>

Carry on...
 
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you don't need to enter in every intersection along your route. just put the starting point and ending point. the victor airway is defined by those two points. it's usually only a couple of degress off from your VOR indications.

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You probably could do that just as well, but then you're going to have a heck of a time maintaining situational awareness....
 
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you don't need to enter in every intersection along your route. just put the starting point and ending point. the victor airway is defined by those two points. it's usually only a couple of degress off from your VOR indications.

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You probably could do that just as well, but then you're going to have a heck of a time maintaining situational awareness....

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Especially with that color moving map....
grin.gif
 
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you don't need to enter in every intersection along your route. just put the starting point and ending point. the victor airway is defined by those two points. it's usually only a couple of degress off from your VOR indications.

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You probably could do that just as well, but then you're going to have a heck of a time maintaining situational awareness....

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Especially with that color moving map....
grin.gif


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Smarty Pants....
grin.gif


Seriously though, if you're navigating direct to a point 300 miles away, it'll still show the whole route in that little 2" line, with no way to tell where you are in relation to anything really...am I making sense?
 
use the zoom function and zoom out. that way i won't show the whole route. i never file direct to anywhere unless it's a real short distance. they never give it to me. i found it easier to flie airways then ask for direct once airborne.
 
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you don't need to enter in every intersection along your route. just put the starting point and ending point. the victor airway is defined by those two points. it's usually only a couple of degress off from your VOR indications.

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I guess I don't follow. You're saying to put in the two VOR's and forget about the rest of the defining intersections because its "close enough?" Apparently you don't do much airway flying. You can't just cut corners because you didn't feel like entering the intersection where the airway turns. Or am I misunderstanding (I hope)?

confused.gif
 
reread my post. if the airway dog legs, obviously you would enter that intersection but lets say there is a 100nm staight line distance between two VOR's. you don't need to enter in every intersection between the two. unless that intersection is significant for some reason. that airway is defined by the two VOR's. the poster wondered why the gps unit doesn't specifically let you enter for example: V212. if you put in the FPL, ABC VOR to DEF VOR, the line drawn between the two would be V212. you don't need to enter in intersections that define radials off adjacent VOR's if there are any on V212. UNLESS, you need to make a course change/altitude change etc. at one of those fixes. hope this clarifies a little
 
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Should be, but unfortunately, there isn't. At least not yet...one would think Garmin could come up with a simple update to fix that.

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Garmin is currently working on Victor airway planning. The formerly UPS (now Garmin) CNX80 currently has it and I read Garmin is working on incorporating the technology into the 430-530. The problem has something to do with the way the database info is stored.
 
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2) 2. May ATC initiate a GPS-only approach?

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I don't think so, even if you file /G (indicating enroute/terminal capability). They will assume you have no GPS approach capability unless they ask you, or if you offer that information.

Example: I was flying to UNI one day; filed IFR /G (I had a current GPS database so I was terminal/enroute capable and also capable of GPS approaches and DME/NDB substitution). The NDB was out of service, which meant that the ILS and NDB approaches were not available because they both required an operational NDB. When I was given the handoff to the last ATC controller, he advised me that the ILS and NDB approaches were unavailalbe and asked my intentions. He didn't assume that I could shoot a GPS approach (nor did he offer one).

I asked to shoot the ILS and substitute GPS for the NDB (perfectly OK with a current database - I could have done a GPS approach too). ATC accepted that, and I did the ILS without any problems.

2 other things: Avweb.com has a columnist named Don Brown who is an ATC guru. He writes some good articles on ATC issues for pilots, including some good info and tips on using GPS for IFR. Also the latest issues of Aviation Safety feature a series of articles on "tips and tricks" for using the 430/530.

Fly Safe!
 
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How are Victor airways programmed into the unit? What if the airway has a dogleg

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Here's a quick question - why would you want to do this anyway? The beauty of IFR GPS is filing direct (mostly) and not being restricted to airways.

OK, there are situations where you may need to fly a portion of an airway even with GPS (i.e. filing an SID/STAR or a preferred route). Just play by the /G IFR filing rules (i.e. filing between arrival/departure fixes and using fixes within each center airspace, etc.). Also, like others have said, maintain your positional awareness and keep charts handy as a backup plan in case your GPS craps out - that way you can merge into a nearby VOR/airway routing and continue with your trip for the time being.
 
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How are Victor airways programmed into the unit? What if the airway has a dogleg

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Here's a quick question - why would you want to do this anyway? The beauty of IFR GPS is filing direct (mostly) and not being restricted to airways.

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A good reason for doing this is flying with a database that's not current. As long as the intersections and VORs haven't been moved*, it's a good way to fly the airways without having to use the VOR recievers.

As long as you have the charts handy, and you do your homework, there's no reason you can't do this.

*Another reason to use the JEPP charts...all of the changes are clearly pointed out to you...
 
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