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

[Chris Ellington]

I've started IFR training about two months ago in a plane with Dual VR's, one with GS the other with a built in indicator. I have no DME. Eight years ago when I bought my plane it would have been plenty good to learn IFR and augment with a few hours in a plane with GPS.

Fast forward to today and it's becoming difficult to find approaches we can fly if you are VOR only. Many approaches require DME, which I don't have, and the few we do find close to Louisville or surrounding areas have a Marker Beacon down or ILS NOTOM as no-op every time I have a lesson. I'm looking to upgrade to a GPS175 most likely. I don't see it getting better, every month it seems another VOR or LOC disappears off the map. GPS (WAAS or Non-WAAS) is the future if you are flying IFR.

 

[timwinters]

This airplane equipped with a millennial anti-stick-and-rudder skill (and general piloting skills) development device:

 

[N1120A]

GPSS turns even a very basic STEC 30 into an incredibly solid AP option.

 

[BrianNC]

GPSS turns even a very basic STEC 30 into an incredibly solid AP option.

We have a STEC 30 in our club plane but no GPSS. The GPSS turn it into a full-function autopilot with glidescope capture, etc?

 

[N1120A]

We have a STEC 30 in our club plane but no GPSS. The GPSS turn it into a full-function autopilot with glidescope capture, etc?

You still need to manage pitch and power on the approach. The GPSS will hold the LNAV side

 

[dell30rb]

The utility of technology and WAAS will hit you the first time you are on a trip somewhere when worsening unforecast conditions at your destination and alternate make your fuel planning questionable, so you divert for a drink of fuel based on some information you got from Foreflight and ADS-B, and pop out at 300 AGL at a podunk airport in SC with cheap 24 hr self-serve

 

[N1120A]

The utility of technology and WAAS will hit you the first time you are on a trip somewhere when worsening unforecast conditions at your destination and alternate make your fuel planning questionable, so you divert for a drink of fuel based on some information you got from Foreflight and ADS-B, and pop out at 300 AGL at a podunk airport in SC with cheap 24 hr self-serve

Absolutely. It will also hit you when you go to a busy airport that never had an ILS put in and you are happy you don't have to divert somewhere when the marine layer and ground fog combine to bring your ceilings to 200-250 AGL.

 

[Jabe Luttrell]

I got my IFR back in '70. I had one tube navcom and an adf. I felt that I could fly anywhere, even ILSs. To fly to Nantucket from Hartford I just turned in the consolan and flew direct. Of course half my flying was to the avionics shop to get the navcom retubed and retuned. I eventually got 2 navcoms and a DME. Later a simple stormscope. Then a loran, which was more of an attention diversion. I was in clover with the multisense rnav unit. I could move cord and fly off airways on routes of my creation, except I could never get a direct clearance in the Northeast. I upgraded to the king 150 and thought it was all I needed. When I bought my Cessna 340 it had a Garmin 530W and a 296 with wires hanging behind and in front of the panel. I cleaned up the panel with a second 530W, a Garmin 345, transponder with ADSB in and out and with coupling to my three axis autopilot. Life is good. The 345 sends data to my foreflight and my headset. Now I'm more of a flight manager. At 1000 feet I engage the autopilot and fly coupled almost to the flare. My wife caters the flight, we're in smooth air mostly on top. I spend most of the flight actually staying ahead of the airplane, checking weather, looking for traffic, briefing the approach in relaxed contemplation. In short, I like the new technologies. You can say I don't have the newest and I probably won't have the budget to get the latest whizbang. All my budget now goes to gas and database subscriptions. I appreciate the extra 50 pounds of payload getting rid of paper charts and approach plate books afforded me. I will just have to imagine what heads-up display and touch screen and GPSS benefits will offer me. I know I'm in the dark ages with adjusting the HSI at every course change demand from the WAAS. That's my burden. A question. Do I have to do VOR checks every 30 days if I don't use VORs for navigation or if there are no VORs?

 

[aterpster]

I know I'm in the dark ages with adjusting the HSI at every course change demand from the WAAS.

That is because your HSI doesn't auto-slew. It has nothing to do with WAAS, as such.

 

[Jabe Luttrell]

You're absolutely correct. But that G5 is tempting.

 

[mryan75]

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 is indeed correct.

 

[flyingcheesehead]

I got my IFR back in '70. I could never get a direct clearance in the Northeast.

They still haven't figured that one out.

 

[Ryan F.]

In terms of justifiable cost for added utility (WAAS), we're there and have been there for some time now. The proliferation of LPV approaches throughout the nation has reinforced that.

When I do my Florida to Jersey (or vice versa) trip in my PA-30 every other month or so I usually stop at a small country airport for inexpensive fuel. The majority of these airports are no longer serviced by NDB or VOR approaches, it's GPS only. With LPV, you've got precision-like minimums in most cases. In low weather -- which is not atypical -- these airports simply wouldn't be available to me. WAAS really has increased the utility of my aircraft.

I think casual IFR pilots could be given a pass for "passing up" LPV. If you're just looking to punch through a layer, cruise, and land in VMC at your destination, there's no real pressing need for WAAS.

 

[Bill]

More Background: The giant, now empty mall, SW of the field

Century III? Back in the day that was THE mall.

 

[AA5Bman]

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

Is this true? If so, I'm surprised I didn't know this.

Does this mean that you wouldn't be legal to fly a non-precision RNAV approach into an airport that has no other approaches?

 

[Bill Watson]

Century III? Back in the day that was THE mall.

You just want to make me feel old. I learned to fly at KAGC before the mall went up, I came back long after it’s heyday.

When malls were hot, I was in NYC.


Sent from my iPad using Tapatalk Pro

 

[hindsight2020]

Is this true? If so, I'm surprised I didn't know this.

Does this mean that you wouldn't be legal to fly a non-precision RNAV approach into an airport that has no other approaches?

No, you can shoot the approach legally all day. You just can't use that airport as a filed alternate. Your filed alternate airport merely has to have something other than GPS-only approaches, if your GPS is non-WAAS.

 

[AA5Bman]

No, you can shoot the approach legally all day. You just can't use that airport as a filed alternate. Your filed alternate airport merely has to have something other than GPS-only approaches, if your GPS is non-WAAS.

Okay that part I remember - the filed alternate has to have another type of approach that doesn’t rely on GPS.

The original comment basically said there had to be a secondary backup for any route you were going to fly, saying - or at least implying - that you’d have to fly VOR airways or have some other non-GPS means of navigating enroute. That’s not true I don’t think, but maybe I’m wrong.

 

[chemgeek]

Okay that part I remember - the filed alternate has to have another type of approach that doesn’t rely on GPS.

The original comment basically said there had to be a secondary backup for any route you were going to fly, saying - or at least implying - that you’d have to fly VOR airways or have some other non-GPS means of navigating enroute. That’s not true I don’t think, but maybe I’m wrong.

From the AIM:

"GPS (TSO-C129 (as revised) or TSO-C196(as revised)) domestic en route and terminal IFR operations can be conducted as soon as proper avionics systems are installed, provided all general requirements are met. For required backup navigation, the avionics necessary to receive all of the ground−based facilities appropriate for the flight to the destination airport and any required alternate airport must be installed and operational. Ground−based facilities necessary for en route and terminal operations must also be in service."

 

[Palmpilot]

From the AIM:

"GPS (TSO-C129 (as revised) or TSO-C196(as revised)) domestic en route and terminal IFR operations can be conducted as soon as proper avionics systems are installed, provided all general requirements are met. For required backup navigation, the avionics necessary to receive all of the ground−based facilities appropriate for the flight to the destination airport and any required alternate airport must be installed and operational. Ground−based facilities necessary for en route and terminal operations must also be in service."

Which version of the AIM are you quoting from? I'm not finding that passage in the 8-15-19 version. What I find is the following in AIM 1-1-17b2(a)(2), which seems to leave the status of ground-based navaids ambiguous:

"Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for navigation under IFR must be equipped with an alternate approved and operational means of navigation suitable for navigating the proposed route of flight. (Examples of alternate navigation equipment include VOR or DME/DME/IRU capability). Active monitoring of alternative navigation equipment is not required when RAIM is available for integrity monitoring. Active monitoring of an alternate means of navigation is required when the GPS RAIM capability is lost."
​

AIM 1-1-17b2(a)(2)

 

[flyingcheesehead]

I think casual IFR pilots could be given a pass for "passing up" LPV. If you're just looking to punch through a layer, cruise, and land in VMC at your destination, there's no real pressing need for WAAS.

Maybe not a "pressing need" but there are still several reasons why it's a good idea. For example, emergencies. You could be on top of your layer fat, dumb, and happy until your engine eats a valve, you lose one cylinder and there's metal clanging around in the rest giving you an indeterminate amount of time to remain aloft. In that case, I'm finding the nearest approach with a glideslope and taking it all the way to the ground if necessary. If you get WAAS, there's now at least 20x more airports with vertically guided approaches, and most of them have ILS-like minimums (200-250 feet AGL). In fact, I'd take an LPV over an ILS at that point.

You also get some back on resale, plus it'll be easier to sell your plane.