Why does my Garmin GPS let me choose an ILS/LOC approach?

[Salty]

It has no nav radio and it does throw an alert up that it's not approved, but it let me choose it and it did provide lateral guidance but no glide slope.

I'm confused why it would even be a choice. The GPS is a GNC-355.

 

[luvflyin]

It has no nav radio and it does throw an alert up that it's not approved, but it let me choose it and it did provide lateral guidance but no glide slope.

I'm confused why it would even be a choice. The GPS is a GNC-355.

So you can follow along and use the information it provides. Fer instance, if yer shootin an ILS that needs DME and you ain't got no DME, it is an authorized substitute. You can fly the needles using your Navs and CDI and get the DME from the GPS. Being able to load the Approach makes it easy because you get the Named fixes. It tells you when you are over them so you don't gotta do a bunch of math. And it's got the moving Map thingy that helps with positional awareness. etc

 

[Salty]

if yer shootin an ILS that needs DME and you ain't got no DME, it is an authorized substitute.

Light bulb going off! Thanks, that makes perfect sense now.

 

[RussR]

Also, other than final, you can fly everything else using GPS navigation for course guidance - such as feeder routes, procedure turns, missed approach, holding patterns, etc.

 

[flyingron]

My Garmin 195 I bought back in 1995 (I think it's serial number #9) has ILS approaches and you can't use it to do anything IFR (other than "situational awareness").

 

[luvflyin]

Also, other than final, you can fly everything else using GPS navigation for course guidance - such as feeder routes, procedure turns, missed approach, holding patterns, etc.

@Salty , just calling your attention to this

 

[Salty]

@Salty , just calling your attention to this

Yeah. I'm not that excited about that scenario, I wouldn't "plan" on using that functionality, but it is nice to understand it in case of some failure scenario. In other words, I would be unlikely to intentionally plan a route where I'd use ILS and want the gps for nav, but I can see a situation where I might want it in a pinch.

 

[luvflyin]

Yeah. I'm not that excited about that scenario, I wouldn't "plan" on using that functionality, but it is nice to understand it in case of some failure scenario. In other words, I would be unlikely to intentionally plan a route where I'd use ILS and want the gps for nav, but I can see a situation where I might want it in a pinch.

K. Just wanted to make sure you saw what @RussR had to say. DME substitute is just one thing

 

[Salty]

K. Just wanted to make sure you saw what @RussR had to say. DME substitute is just one thing

I get it, thanks. I just really like the DME substitute thing. Hadn't considered it at all.

 

[Bill]

I get it, thanks. I just really like the DME substitute thing. Hadn't considered it at all.

I was asked to fly a VOR/DME arc approach using the GPS in lieu DME of on my recent IPC. Yeah, that was fun.

 

[RussR]

Yeah. I'm not that excited about that scenario, I wouldn't "plan" on using that functionality, but it is nice to understand it in case of some failure scenario. In other words, I would be unlikely to intentionally plan a route where I'd use ILS and want the gps for nav, but I can see a situation where I might want it in a pinch.

I wouldn't discount it quite that much. Consider an ILS approach with a procedure turn and a missed approach using multiple crossing radials and such. I'd much rather load it up in the GPS, use that for all the "complicated" navigation (including using an autopilot in GPSS mode, if so equipped), then just switch my attention over to my ILS receiver for final, then back to the GPS for the missed.

I would consider the use of radials and intersections and such other than final to be the backup, to be used only if the GPS failed.

When I teach autopilot use, I teach exactly that - GPSS for everything until final, switch to APPR mode prior to the FAF (typically required to activate the GS capture circuitry) and then once we go missed, back to GPSS. That's the most precise way for the autopilot to fly it, and works well.

Eve if we're just getting vectors to final, having the approach loaded into the GPS still gives you the advantage of increased situational awareness, fix crossing, etc., and of course it is ready for the missed approach if you need it.

 

[Salty]

I wouldn't discount it quite that much. Consider an ILS approach with a procedure turn and a missed approach using multiple crossing radials and such. I'd much rather load it up in the GPS, use that for all the "complicated" navigation (including using an autopilot in GPSS mode, if so equipped), then just switch my attention over to my ILS receiver for final, then back to the GPS for the missed.

I would consider the use of radials and intersections and such other than final to be the backup, to be used only if the GPS failed.

When I teach autopilot use, I teach exactly that - GPSS for everything until final, switch to APPR mode prior to the FAF (typically required to activate the GS capture circuitry) and then once we go missed, back to GPSS. That's the most precise way for the autopilot to fly it, and works well.

Eve if we're just getting vectors to final, having the approach loaded into the GPS still gives you the advantage of increased situational awareness, fix crossing, etc., and of course it is ready for the missed approach if you need it.

I get it. What I'm saying is that I don't expect to be using ILS as plan A. It would only be if something bad happened. I plan on being a "fair weather" IFR flier.

 

[Salty]

Also, I think my response about DME was misleading. It wasn’t that dme is that exciting, it was just a simple example that turned the light on to the value of the feature.

 

[RussR]

I get it. What I'm saying is that I don't expect to be using ILS as plan A. It would only be if something bad happened. I plan on being a "fair weather" IFR flier.

Ah, okay - I read it as "If I'm flying an ILS, I would only load it into the GPS as a backup", which I took to mean you'd rather do VOR navigation and cross-radials and such...

 

[Salty]

Ah, okay - I read it as "If I'm flying an ILS, I would only load it into the GPS as a backup", which I took to mean you'd rather do VOR navigation and cross-radials and such...

Yeah, GPS approach would be my plan A because I don't expect to need precision minimums unless things go sideways.

 

[Palmpilot]

Attached is an example of where I would fly the ILS even if the ATIS were saying that I could get in with RNAV minimums. The time I landed there, the ATIS was saying that the ceiling was 400, but it was really more like 250. (I suspect that's not unusual on the Oregon coast.)

 

[aterpster]

My Garmin 195 I bought back in 1995 (I think it's serial number #9) has ILS approaches and you can't use it to do anything IFR (other than "situational awareness").

I still have one as a paper weight. You may recall it had IAPs in it for a time.

 

[flyingron]

I'm pretty sure mine still does, but its way out of date.

The last time I think I actually used it was in 2004 or so when I was flying around Australia. To my surprise, the thing had all the Aussie airports in it.

 

[aterpster]

I'm pretty sure mine still does, but its way out of date.

The last time I think I actually used it was in 2004 or so when I was flying around Australia. To my surprise, the thing had all the Aussie airports in it.

Does Garmin still sell updates for it?

 

[flyingron]

Don't know. Haven't tried. For a while they'd update them in the Garmin booth if you brought it in.

 

[Groundpounder]

I used to fly for a PC-12 fleet operator that just had KLN-90B's for a GPS, and it didn't have any ILS approaches in it. We'd have to enter them manually. A last minute runway change would lead to quite a bit of flailing around in the cockpit.

 

[N1120A]

Remember, except for an ILS, you can use a WAAS GPS for primary navigation on the entire approach on any non-precision ground based approach, so long as you are monitoring the nav aid on a secondary receiver.

Yeah, GPS approach would be my plan A because I don't expect to need precision minimums unless things go sideways.

The vast majority of the time, an LPV has the same minimums as the ILS. Some, in fact, have better minimums.

Attached is an example of where I would fly the ILS even if the ATIS were saying that I could get in with RNAV minimums. The time I landed there, the ATIS was saying that the ceiling was 400, but it was really more like 250. (I suspect that's not unusual on the Oregon coast.)

Can you technically fly that ILS without an ADF?

 

[Salty]

Can you technically fly that ILS without an ADF?

 

[luvflyin]

Remember, except for an ILS, you can use a WAAS GPS for primary navigation on the entire approach on any non-precision ground based approach, so long as you are monitoring the nav aid on a secondary receiver.



The vast majority of the time, an LPV has the same minimums as the ILS. Some, in fact, have better minimums.



Can you technically fly that ILS without an ADF?

What do you mean by “technically.”

 

[N1120A]

What do you mean by “technically.”

It says ADF required. Does GPS replace an ADF like it does DME for approach purposes that aren't NDB approaches?

 

[RussR]

It says ADF required. Does GPS replace an ADF like it does DME for approach purposes that aren't NDB approaches?

Yes. AIM 1-2-3.