Yesterday I requested and was eventually cleared direct to an intermediate fix (IF) on a LPV GPS approach. My 430w wanted to turn me outbound from the IF towards the IAF and I never got a glideslope needle.
Flew approach to intermediate fix yesterday
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tsts4
Pattern Altitude
What was the approach? I’m guessing if you wanted to fly the approach from the IF and not the IAF that you needed to activate the leg from the IF to the FAF. Otherwise the 430 wasn’t seeing the IF waypoint as part of the approach but rather at that point just as an enroute waypoint which is why it wanted to turn you to the IAF.
luvflyin
Touchdown! Greaser!
Where were you when you ‘activated’ the Approach? Which IAF was the Approach from when it was ‘loaded?’
EDIT: I ran it on a simulator. Old data base. Drone was an IAF and that’s the one I used. I loaded and activated the Approach. Then I went to FPL, put the cursor on PEFOC, pushed the menu button and selected ‘activate leg.’ That made SEZJY PEFOC the active leg and gave my present position direct to SEZJY as the DTK. It took me to SEZJY and when getting close changed from TERM to LNAV+V and the psuedo glideslope worked just fine. I think you’d get the same results using RONKE or FKN for IAF and get LPV needles, mayby after SEZJY but before PEFOC.
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RussR
En-Route
I see why it didn't work. You loaded the approach via the IAF, then when direct to the IF (presumably via the FPL button, then cursoring down to the IF, Direct, Enter, Enter). But when you Activate the approach, it sends you to the IAF you selected when you loaded it.
What you should have done was selected the approach via one of the IAFs, then activated it. THEN gone in FPL and selected the IF, Direct Enter Enter. Then the approach would have worked.
It's the order of operations. When you activate the approach, the GNS430W assumes you don't want to do anything else you might have in your flight plan, you want to fly the approach from the IAF you had previously selected. And so it takes you directly there.
What you should have done was selected the approach via one of the IAFs, then activated it. THEN gone in FPL and selected the IF, Direct Enter Enter. Then the approach would have worked.
It's the order of operations. When you activate the approach, the GNS430W assumes you don't want to do anything else you might have in your flight plan, you want to fly the approach from the IAF you had previously selected. And so it takes you directly there.
Yes this is what happened.
I am in the process of acquiring an IFD 440. I wonder if it behaves the same. my 430W will be in the classifieds soon.
aterpster
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aterpster
I don't believe you ever need to activate an approach. Activate is really direct-to the selected IAF or feeder fix. I did it in a G500W trainer. I loaded the approach with the VOR as my selected IAF. I positioned myself at WAIKS on V189 north of Franklin VOR. I then went into FPL and executed a direct-to SEZJY. Trainer went direct to SEZJY and turned inbound at SEZJY. Terminal changed to a green LPV passing SEZJY inbound.
RussR
En-Route
Well, on further research, I learned something today - it appears you are correct, you don't always need to activate the approach. Thanks Wally. This assumes that you have loaded the approach AND have selected to go direct to one of the waypoints in the FPL prior to the FAF. However, if you have loaded the approach through the typical "Direct - Airport, PROC, select approach" method, then you will still be flying direct to the airport until you either activate the approach (sending you direct to the IAF) or manual select direct-to from the FPL page.
I can see where this would be useful in the "cleared direct to the IF" scenario, especially if using an autopilot to navigate.
I will add that I was unable to find anything covering this in the 430W Pilot's Guide and Reference - it only mentions having to activate the approach.
labbadabba
Pattern Altitude
If need be, you can always set the 430 to activate "Vectors-to-Final" once you're on the IF. Probably the quickest way to get the unit to show you what you want to see.
James331
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I've flown a few via the IF, if the approach is activated and you have some IAF selected, after you got your new clearance you should be able to go direct enter enter to the IF and it should still sequence the rest of the approach.
Also I'd keep the garmin if it were me.
Also I'd keep the garmin if it were me.
aterpster
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aterpster
Not covered in those manuals. But, it is in later manuals, such as the Cessna G-1000.
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Interesting posts thanks for the feedback.
I had planned to fly the whole approach from the IAF but diverted left of course significantly for WX. The diversion had me coming in significantly north of the IAF. It was much more direct to just go to the IF.
I had planned to fly the whole approach from the IAF but diverted left of course significantly for WX. The diversion had me coming in significantly north of the IAF. It was much more direct to just go to the IF.
luvflyin
Touchdown! Greaser!
Thanks for starting it. I finally figured out something that hadn't been making sense to me by comparing @aterpster 's and @RussR 's scenarios in posts 8 and 9.
I always liked having as much as possible in my active flightplan. That way, if I need a waypoint it's in the flightplan and I don't have to go find it whoknowswhere. Also, learn to use the OBS mode. It is very useful.
luvflyin
Touchdown! Greaser!
Seems I remember reading that they, Garmin anyway, started putting all the fixes along the Approach course up when you did VTF instead of just the FAF. That would make it not quite the problem it once was. I haven’t tried it to see.
Garmin updated the GTN software to add the other fixes in a straight line to the FAF. But it does not, for example, select or show one of a number of IAFs or pick a side for you on a T-configuration approach.
There's a bit of reasonable disagreement on this, but I'm with the group which has not seen any need to change my SOP. When I brief an approach, I select a suitable IAF and load the approach starting with it, whether GNS, GTN, G1000 or IFD.
aterpster
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aterpster
As Mark says, only those waypoints that are aligned with the final portion of the intermediate segment. That's my recollection.
RussR
En-Route
Why never activate an approach? While, as discussed, the unit will auto-activate if you have loaded an approach and then gone direct to one of the fixes on the approach from your FPL screen, I see no disadvantage to activating it if you actually do want to go to the IAF you selected when you loaded it. Requires fewer button presses at least.
Operational consistency. Basically, it works without it in all circumstances and removes the need to make a "should I activate?" decision.
aterpster
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aterpster
As Mark says, operational consistency. And, how often are you in a position to go direct to the selected IAF or feeder fix when you load an approach?
Also, an RNAV approach doesn't auto-activate. It switches from terminal to approach mode if within prescribed angles of the FAF and passing the fix prior to the FAF. "Activate" is a misnomer in this context.
With the old VTF if would go into approach mode 30 miles from the ARP. I don't believe that is the case with the enhanced VTF mode.