A reminder for why you want WAAS GPS if you fly IFR

[chemgeek]

There have been a few threads recently about training in or owning VOR-only equipped aircraft for IFR flight. I just completed a trip to Pittsburgh and back, where the utility of flib-flying IFR and WAAS GPS was reinforced. If you were flying this trip IFR with VOR only, you would be pretty much SOL or would been limited to other options that may not have been as weather or winds friendly, as the Elmira and Clarion VOR are out of service (Elmira permanently). Utica, Ithaca and Georgetown are also on the chopping block in 2021. That will leave our area pretty much without functional airway VORs as we move to the minimum operating network.

With IFR GPS, the trip as routed was no problem, including shooting the GPS 35 into the home field on the return trip with 1000 OVC conditions. (Can't do that without GPS, as the VOR approach is OTS, and in reality permanently decommissioned.)

The return trip was particularly nice, cruising at 9000 well above the tops, catching what little tailwind there was with a passing trough, spending only 20 minutes in the clag on the descent to the IAF and conducting the approach. A 2 1/2 hour flight beats a 7 hour drive any day, even if you are only able to stare at cloud tops most of the way. My only complaint is that the rate-based (S-TEC) autopilot flies like a drunken sailor in the bumps on approach. It's smoother to hand fly and I usually turn it off at the IAF. I perhaps exaggerate a bit. The AP holds track OK, but it isn't always smooth and pretty. It's rock solid in cruise in smoother air.

 

[BrianNC]

IFR GPS for sure. Doesn't necessarily need to be WAAS though, but preferred.

 

[dmspilot]

What's this have to do with WAAS?

 

[PilotRPI]

I did the first half of my training vor/loc/ils only. It was great to really get your mind into understanding position and approaches. Switched to a 430 later and it felt like cheating. Happy I learned a bit with just vors, but for practical purposes, gps makes the real deal a lot easier.

 

[BrianNC]

I did the first half of my training vor/loc/ils only. It was great to really get your mind into understanding position and approaches. Switched to a 430 later and it felt like cheating. Happy I learned a bit with just vors, but for practical purposes, gps makes the real deal a lot easier.

Got my instrument in '02 and didn't even have a GPS. Times have changed.

 

[benyflyguy]

My home field had a VOR a few miles away forever. Decommissioned about two years ago. Our field has two RNAv approaches as well as a localizer approach. So it was nice you could do one without gps. But since the VOr went down the missed is a gps fix. A lot of locals got ****ed about now needing gps to fly IFR into our field.

 

[chemgeek]

What's this have to do with WAAS?

Can't fly an LPV without it.

 

[Chip Sylverne]

Install a gpss. Rock solid right up to the FAF.

 

[BrianNC]

Can't fly an LPV without it.

But you can still use the GPS for the RNAV approach, just not a 'precision' one. So WAAS isn't needed per se. But I'd rather have it of course.

 

[dmspilot]

Can't fly an LPV without it.

I didn't realize your story was about LPV approaches. I thought it was about the lack of enroute VORs.

 

[EdFred]

If it's a .129 GPS (non waas) unit don't you need to have an alternate nav source, but with a .146 (waas) unit you're good as that being the only nav system on board? Or did that change?

 

[Bill Watson]

I’ve been flying regularly into Pittsburgh, KAGC that is, for the past 5 years or so. I come from the other direction (Durham NC) but similar in the sense that a 1.75 hour flight beats the 7-8 hour car trip required to get over the Appalachians.

I first learned for fly in the 70s but was deeply involved in GPS navigation from day 1 in the 80s due to a loophole in the rules for glider racing; no ground-based navigation aids were allowed. It was meant to keep pilots dependent on pilotage for cross country racing but GPS wasn’t ground based. So we immediately had purpose built panel mounted GPS navigators and glide computers available for glider racing. GPS helped this NJ, then NC pilot get around the race courses laid out around Elmira and Dansville NY in the 80s and 90s.

When I quit glider racing in the 90s I was surprised to find how little GPS navigation had penetrated into most airplane flying. The first generation of handhelds were out there but panel mounts were just beginning to appear. The first Gulf War was underway and I specifically recall reading about A-10 pilots ferrying their navigation-lite aircraft across the Atlantic without GPS(!!). I suspect a few civilian handhelds may have found their way into a few cockpits.

Having acquired a Maule in the mid-90s, I immediately had a 1st gen Garmin 155 Navigator installed. Mastery of the VOR navigation was mandatory but having used GPS exclusively for years in gliders, it was tough not to focus on the GPS.

Now I fly an RV10 which is equipped with a G430w driving a panel full of experimental EFISs and a GPSS capable AP. It flies equally well button pushing or hand flying. Actually it is a bit more accurate and smooth using the buttons.

And going into Pittsburgh’s Allegheny County, I’ve learned that the RNAV 28 is a lot smoother than the ILS 28 which seems to have more humps and bumps in it than most ILSs, though that could be more a function of lousy antenna buried in my wing tips.

RNAV LPV approaches and GPSS capable APs all around!


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[texasclouds]

Interesting thread. My area doesn’t have too many vors out, but I’ve noticed alot of ndbs down. I’ll be watching this thread since I’ve considered getting an ifr non-gps plane. I’m sure after finishing ifr training I’ll better understand the options.

 

[aterpster]

But you can still use the GPS for the RNAV approach, just not a 'precision' one. So WAAS isn't needed per se. But I'd rather have it of course.

Nor LP.

 

[azure]

If it's a .129 GPS (non waas) unit don't you need to have an alternate nav source, but with a .146 (waas) unit you're good as that being the only nav system on board? Or did that change?

That's been my understanding too. OP didn't say what his IFR GPS was, or whether it was WAAS. Possibly implied in a later response? (post #7)

 

[chemgeek]

That's been my understanding too. OP didn't say what his IFR GPS was, or whether it was WAAS. Possibly implied in a later response? (post #7)

I have a GNS-430W, of course, hence the title of the post. With a c129 TSO (non-WAAS) GPS navigator, you still must legally have equipment on board to fly the proposed route, which means if the VORs are OTS along your route of flight, you can't legally fly it. A c145/146 TSO (WAAS) unit can be used for stand-alone navigation. And of course you get the much lower minimums of LPV vs. LNAV approaches where available. At my home field the LPV has a DA of around 250 AGL, compared to around 850 AGL with LNAV. So with the airport reporting 1000 OVC, there was no question of getting in safely with LPV minimums.

 

[chemgeek]

Install a gpss. Rock solid right up to the FAF.

Good to know. That's next on my list when the vac instruments come out for a couple of G5s and the GAD29, which enables GPSS with the S-TEC AP.

 

[chemgeek]

I’ve been flying regularly into Pittsburgh, KAGC that is, for the past 5 years or so.

That's where I flew in. Nice airport and friendly FBO. The ILS is offset from the runway by a 2 degrees, which looks weird on breakout. I think the RNAV is aligned with the runway. I've always found the LPV approaches very easy to fly, even more so than the comparable ILS.

 

[azure]

I have a GNS-430W, of course, hence the title of the post. With a c129 TSO (non-WAAS) GPS navigator, you still must legally have equipment on board to fly the proposed route, which means if the VORs are OTS along your route of flight, you can't legally fly it. A c145/146 TSO (WAAS) unit can be used for stand-alone navigation. And of course you get the much lower minimums of LPV vs. LNAV approaches where available. At my home field the LPV has a DA of around 250 AGL, compared to around 850 AGL with LNAV. So with the airport reporting 1000 OVC, there was no question of getting in safely with LPV minimums.

Doh!

Yep, interestingly enough my instrument DPE didn't know this, and thought you needed to do a RAIM calculation even with WAAS, and alternate equipment suitable for the route. I was prepared to back up my argument with the FAR/AIM, but my CFII was there and came to my defense (this was in 2013, before the ban on CFIs during orals).

It has never been an issue for me as I have a CNX-80 (aka GNS480). As you say, I would not be comfortable flying in today's NAS without a WAAS GPS. My very first solo excursion into IMC, it came in handy when ATC offered me a LOC BC with a 500 AGL MDA, but I asked for the LPV instead. I would not have gotten in on the LOC BC.

At my current home base, we have both an ILS and an RNAV with LPV minimums, but the ILS is frequently OTS, so I'm very pleased to have the capability to fly the LPV.

 

[Bill Watson]

That's where I flew in. Nice airport and friendly FBO. The ILS is offset from the runway by a 2 degrees, which looks weird on breakout. I think the RNAV is aligned with the runway. I've always found the LPV approaches very easy to fly, even more so than the comparable ILS.

That offset looks weird in synthetic vision while still embedded in the soup. I stopped flying it in low conditions and just opt for the LPV.

I took my first flying lessons back in ‘71 at KAGC flying out of the little hangar attached to the Corp Air FBO building. Brings back a lot of memories...can’t understand why it was so hard to land on the big wide runway back then!


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[chemgeek]

That offset looks weird in synthetic vision while still embedded in the soup. I stopped flying it in low conditions and just opt for the LPV.

I took my first flying lessons back in ‘71 at KAGC flying out of the little hangar attached to the Corp Air FBO building. Brings back a lot of memories...can’t understand why it was so hard to land on the big wide runway back then!

It's a neat airport. There is not a single flat spot around the field. The exit road leads to several roads that go up and down at least 50-75 feet in elevation around the field. And on the west side, the main road goes through a tunnel underneath the main runway. It seems that the airport grounds are the only flat spot in the area. I assume they must have moved a lot of earth to do that. Very convenient to the city and the Eastern burbs. Reasonable avgas price and $15 parking, plus rental cars on site. There ARE good metro FBOs around. I'll use them again if I'm back in the Pittsburgh area.

 

[Plano Pilot]

I wonder how I navigated all over North America for decades, and also did a trip to Europe and back without GPS. Back in 78 I also did a round trip Dallas to Oshkosh using only an, ADF and printed maps. Yes there were times where we had no reception. Plot your course and track it outbound from your last navaid. When you pickup your new one track it. By they way I have shot hundreds of ADF approaches.

That is nothing compared to what my dad did back in the Low Frequency Radio Range days. Can you believe they shot approaches listing to _. or ._? https://en.wikipedia.org/wiki/Low-frequency_radio_range

 

[Bill Watson]

It's a neat airport. There is not a single flat spot around the field. The exit road leads to several roads that go up and down at least 50-75 feet in elevation around the field. And on the west side, the main road goes through a tunnel underneath the main runway. It seems that the airport grounds are the only flat spot in the area. I assume they must have moved a lot of earth to do that. Very convenient to the city and the Eastern burbs. Reasonable avgas price and $15 parking, plus rental cars on site. There ARE good metro FBOs around. I'll use them again if I'm back in the Pittsburgh area.

More Background: The giant, now empty mall, SW of the field is all built on a giant slag dump, as is much of the airport itself. The mall in particular was built on top of a recently active slag dump, that is, red hot slag was dumped there directly from the steel mills in the valley. A train used to run up from one of the nearby mills in the valley and dump it. Quite a sight at night, a sight that was common around town back in the day. I spent a year on leave from college filling up those slag cars at J&L’s blast furnaces in Oakland. Dangerous hot work that was.

That tunnel on the west end of 28 was just being completed as part of the lengthening of 28 when I was learning to fly in ‘71. KAGC was one of the busiest GA airports in the country back then with a bunch of corporate HQs in town like USS, Westinghouse, PPG, Mellon Bank, etc. Typical training flight would have me lined up behind a few corporate jets, a brace of F4s and a half dozen C150s and Cherokees. Now it’s mainly Flexjets, medical ‘copters and just a little bit of training work.

Just about all flat spots in and around Pittsburgh is the product of much filling. Slag, once cooled, could be broken up into a smelly gravel that was used throughout the ‘burgh for roads, lots and fill.

Greater Pitt AP (KPIT) is built on much fill but that was mainly strip mine waste as that whole area west of Pittsburgh had been strip mined pretty heavily. Easily identifiable because vegetation and trees have a hard time growing where there is no top soil. It takes a generation or two before some top soil builds up and normal vegetation can grow again. Great for the filling and grading needed to create and expand an airport though! Ironically, KPIT is now considered to big for its britches and is being downsized with one of it’s 3 parallel runways to be plowed under.

Now, flying southwest of KAGC, the landscape is dotted with fracking operations, just as it was dotted with thousands of beehive coke ovens in 19th century.


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[benyflyguy]

Now, flying southwest of KAGC, the landscape is dotted with fracking operations, just as it was dotted with thousands of beehive coke ovens in 19th century.
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Wanna see fracking? Fly up around KBGM. Westward, hundreds and hundreds truly amazing

 

[Bill Watson]

Wanna see fracking? Fly up around KBGM. Westward, hundreds and hundreds truly amazing

Interesting... when I went to Lycoming’s engine school in Williamsport a few years ago, the hotels were full of fracking folks.
It was becoming a very big deal in the area. Haven’t flown up that way in a while.


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[FlyingTiger]

Just this past Friday I flew from Wyoming Valley, PA to Syracuse, NY and back and got cleared Direct both ways. I have no idea if the lack of VORs had anything to do with it but I was pretty happy.

 

[Ravioli]

Now, flying southwest of KAGC, the landscape is dotted with fracking operations,

Most wells are completed (fracked) in a week or two. Then it's a producing well, not a fracking operation.

 

[steingar]

I wonder how I navigated all over North America for decades, and also did a trip to Europe and back without GPS. Back in 78 I also did a round trip Dallas to Oshkosh using only an, ADF and printed maps. Yes there were times where we had no reception. Plot your course and track it outbound from your last navaid. When you pickup your new one track it. By they way I have shot hundreds of ADF approaches.

Way back when the damn things were everywhere. They're state of the art and they were what you used. Try that now and you're likely to wind up short. VORs are closing all over, there won't be too many left. I doubt I'll be WAAS equipped any time soon, more the pity. Thankfully several fields have ILS here, and there are a couple VORs that will be maintained.

 

[Captain]

My plane doesn't have WAAS but it does have Cat IIIb auto-land....so I guess I don't miss it?

 

[aterpster]

My plane doesn't have WAAS but it does have Cat IIIb auto-land....so I guess I don't miss it?

You own a plane with CAT IIIb auto-land? You must really be loaded.

 

[Captain]

Should have put quotes around “my”.

 

[mryan75]

There have been a few threads recently about training in or owning VOR-only equipped aircraft for IFR flight. I just completed a trip to Pittsburgh and back, where the utility of flib-flying IFR and WAAS GPS was reinforced. If you were flying this trip IFR with VOR only, you would be pretty much SOL or would been limited to other options that may not have been as weather or winds friendly, as the Elmira and Clarion VOR are out of service (Elmira permanently). Utica, Ithaca and Georgetown are also on the chopping block in 2021. That will leave our area pretty much without functional airway VORs as we move to the minimum operating network.

With IFR GPS, the trip as routed was no problem, including shooting the GPS 35 into the home field on the return trip with 1000 OVC conditions. (Can't do that without GPS, as the VOR approach is OTS, and in reality permanently decommissioned.)

The return trip was particularly nice, cruising at 9000 well above the tops, catching what little tailwind there was with a passing trough, spending only 20 minutes in the clag on the descent to the IAF and conducting the approach. A 2 1/2 hour flight beats a 7 hour drive any day, even if you are only able to stare at cloud tops most of the way. My only complaint is that the rate-based (S-TEC) autopilot flies like a drunken sailor in the bumps on approach. It's smoother to hand fly and I usually turn it off at the IAF. I perhaps exaggerate a bit. The AP holds track OK, but it isn't always smooth and pretty. It's rock solid in cruise in smoother air.

I'm in the same area (KRME). I did the RNAV 35 at Hamilton a few weeks ago as a practice in prep for my IR checkride. We are going to be flat-out of VORs around here in 24 months (in effect we already are, as far as approaches go). I wonder how many areas will be similar in the coming couple years? Because like you said, you pretty much need WAAS GPS to fly IFR around here.

 

[chemgeek]

Yep, when the MON is operational, you may have to reach 5000 in order to receive a VOR. That won't help for an IFR departure from a rural airport. IIRC, the closest MON VORs will be ART and CFB. Good luck picking those up on departure. Its WAAS or bust, or base at a radar equipped airport.

 

[aterpster]

Yep, when the MON is operational, you may have to reach 5000 in order to receive a VOR. That won't help for an IFR departure from a rural airport. IIRC, the closest MON VORs will be ART and CFB. Good luck picking those up on departure. Its WAAS or bust, or base at a radar equipped airport.

WAAS isn't required for an RNAV ODP or RNAV SID. As to procedures, WAAS is required only for LPV and LP IAPs. A pre-WAAS IFR navigator will suffice in all other cases, but with the hassle of RAIM checks.

 

[BrianNC]

WAAS isn't required for an RNAV ODP or RNAV SID. As to procedures, WAAS is required only for LPV and LP IAPs. A pre-WAAS IFR navigator will suffice in all other cases, but with the hassle of RAIM checks.

I think what everyone is really meaning to say is IFR approved GPS. As you said, WAAS isn’t needed in general unless you want the lower minimums of the GPS ‘precision’ approaches.

 

[EdFred]

I think what everyone is really meaning to say is IFR approved GPS. As you said, WAAS isn’t needed in general unless you want the lower minimums of the GPS ‘precision’ approaches.

You also need a back up NAV system if you aren't WAAS. So it's not *just* lower minimums on the LPVs...

 

[alfadog]

Tough crowd

 

[aterpster]

You also need a back up NAV system if you aren't WAAS. So it's not *just* lower minimums on the LPVs...

You better well have that, WAAS or not. The VOR MON program presumes that.

 

[chemgeek]

Non WAAS GPS is fine as long as you don't need a low IFR approach at the end of the flight or for an emergency return to origin. At many non-metro airports, the LNAV may not be sufficient to get you in, necessitating a diversion to a nearby airport with a better (e.g. ILS) approach. At my home airport, for example, the LNAV approaches have minimums of around 800-1000 AGL (depending on approach), which is not all that great, and barely better than the old crappy VOR approach which is now long out of service. If you fly out of a metro airport, and don't fly to the sticks, maybe you don't need WAAS, but if you are at a rural airport, or fly to them, WAAS is very important. The LPV approaches at our airport were a godsend for our frequent clientele, who can now better rely on avoiding diverting because of weather. Same for other rural airports in our area with busy GA operations.

 

[Tarheelpilot]

Got my instrument in '02 and didn't even have a GPS. Times have changed.

My first 121 job was in a jet with no gps. I’m only 40. Things have changed a lot in the last couple decades. Now people look at learning IFR in a non area nav capable aircraft like it’s a crazy idea... I dunno. Pardon me while I go walk up hill in 10 feet of snow to get to work.