Garmin 400 Non Waas--What GPS Approaches Can I Fly?

madriverman

madriverman

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madriverman
Hi guys. Settle a bet...what approaches can I fly with a non-waas GPS?

Thanks!
 
madriverman said:
Hi guys. Settle a bet...what approaches can I fly with a non-waas GPS?

Thanks!
Click to expand...

Non WAAS Garmin 400? No VOR, No ILS. Can't substitute GPS for a ground based nav aid for final approach guidance.

So that leaves GPS LNAV...which is still a lot of approaches.
 
VOR, Glideslope...yessir. So, ILS and RNAV...but wondering about LPV at circling mins, etc...

For example, the RNAV (GPS) Z RWY 17 for KMTJ has a WAAS in the upper left hand corner of the plate. Does that mean, I must have WAAS for the approach, or can I still fly the approach and use the LNAV MDA or Circling Mins on the plate (vs the LPV or LNAV/VNAV DAs)?
 
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Without WAAS you can't do better than LNAV mins. A non WAAS GPS won't annuciate LPV, LP, or !LNAV/VNAV.
 
I found four basic rules for flying GPS without WAAS:

Pilots “may file based on a GPS-based IAP at either the destination or the alternate airport, but not at both locations.”
Pilots may plan for LNAV or CIRCLING minimums only, unless equipped for baro-VNAV.
A preflight RAIM prediction for the destination or the alternate airport is required.
Language left over from AIM 1-2-3(d) and Notice N 8900.218 indicate the non-GPS approach at the other location is required to “be flown without reliance on GPS.”
 
It's not a thing, LPV Circling. Circling applies to an approach. In this case, RNAV/GPS. How you get to the circling minimums is up to the capability of your GPS, which, in this case, is only capable of doing LNAV
 
madriverman said:
VOR, Glideslope...yessir. So, ILS and RNAV...but wondering about LPV at circling mins, etc...
Click to expand...

The Garmin 400 does not have nav/com, so the ILS and LOC approaches are out.

You may have a separate NAV radio providing guidance, but your question was which approaches can you fly with G400 alone.
 
Non waas is going to allow you to fly lateral guidance approaches only. So pretty much anything with LNAV or Circling minimums you can fly.

I am sure there is an exception to this, but most approaches not named "Z" will be flyable for a non WAAS aircraft.
 
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You can fly the RNAV approaches to the LNAV minimum. Basically the same thing as when I fly a G1000 NON-WAAS system. There's a ton of approaches that you can still use.
 
madriverman said:
VOR, Glideslope...yessir. So, ILS and RNAV...but wondering about LPV at circling mins, etc...

For example, the RNAV (GPS) Z RWY 17 for KMTJ has a WAAS in the upper left hand corner of the plate. Does that mean, I must have WAAS for the approach, or can I still fly the approach and use the LNAV MDA or Circling Mins on the plate (vs the LPV or LNAV/VNAV DAs)?
Click to expand...
At this airport if you could ONLY shoot the rnav approaches (not legal I know) with the gps in question you would want to use the Y approach if your landing on 17 because it affords you lower minimums with LNAV only.
 
madriverman said:
For example, the RNAV (GPS) Z RWY 17 for KMTJ has a WAAS in the upper left hand corner of the plate. Does that mean, I must have WAAS for the approach, or can I still fly the approach and use the LNAV MDA or Circling Mins on the plate (vs the LPV or LNAV/VNAV DAs)?
Click to expand...

Yes, you can fly that approach to LNAV minimums with a non-WAAS GPS. I'm curious as to how this is an ambiguous discussion worthy of a bet.
 
Can't you also fly an NDB approach? :goofy:

Edit - In way of answering my own question, I did find the below. I don't know if its true or current but here it is:

"In the United States you are no longer allowed to fly an NDB approach using GPS unless "GPS" appears in the approach title. The GPS overlay program allowing that died when AC 90-94 was cancelled in 2009."
 
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Correct, but can you find any airports which have NDB approaches but don't have an RNAV (GPS) approach or GPS approach? I haven't looked specifically, but I haven't come across one for years.
 
I'm not IFR rated yet but does a Non WAAS Garmin 430 even show a Glide SLOPE indicator on an HSI?
 
Question: anyone shooting an approach let’s say the ceilings are reporting 800’ on the ATIS, have you flown an approach to minimums let’s say 200-500’ and you’re still IMC having to do a missed approach?
 
mandm said:
Question: anyone shooting an approach let’s say the ceilings are reporting 800’ on the ATIS, have you flown an approach to minimums let’s say 200-500’ and you’re still IMC having to do a missed approach?
Click to expand...
has anyone gone missed in actual? Yes, but not those numbers per se.
 
mandm said:
Question: anyone shooting an approach let’s say the ceilings are reporting 800’ on the ATIS, have you flown an approach to minimums let’s say 200-500’ and you’re still IMC having to do a missed approach?
Click to expand...
I can’t say that I’ve flown an approach where the ceilings were 300 to 600 feet lower than the AWOS or ATIS report.

I could conceivably happen at a nontowered airport when conditions are very variable, but I would be very surprised to be surprised at a towered airport where controllers are requesting ceiling reports (Memory: I felt like such a pro when I gave one in my first solo IFR flight!).
 
mandm said:
Question: anyone shooting an approach let’s say the ceilings are reporting 800’ on the ATIS, have you flown an approach to minimums let’s say 200-500’ and you’re still IMC having to do a missed approach?
Click to expand...
One of my last ILS approaches was nearly so…home field was reporting 800 ceiling, the ILS has a 200 agl minimum…I’m on the approach expecting to break out at 1550 msl or so (750 msl field elevation)…I’m descending…1500, 1400, 1300, still in soup, 1200, 1100…I have a brief moment of panic as my first thought was, “oh god my altimeter is wrong”, but I cross checked with the gps and they are congruent…then finally break out about 1050 msl / 300 agl…I called the tower and reported the discrepancy. They passed it along to a CJ on approach behind me, and while taxiing to the hangar I heard the CJ report the same breakout height. Just a low cloud over the approach end of the runway.

I hangar at a large class c with 8000+ foot runways. I’m not sure if the ceilings are measured at only one spot or many, but if only one spot it would help to explain why I find the atis ceilings usually off a bit.
 
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Language left over from AIM 1-2-3(d) and Notice N 8900.218 indicate the non-GPS approach at the other location is required to “be flown without reliance on GPS.”​
Click to expand...
​
I wonder if this has gotten a lot worse for non-WAAS owners since many approaches say “GPS Required” to determine distances for the approach.​
Eg the DME’s are inop and they expect you to use your RNAV system to identify fixes/crossings with distance.​
That cuts-out a lot of possible ILS/LOC alternate options because many need Distance Measuring to determine the step down fixes.​
 
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