WAAS vs. Non-WAAS GPS

[GSDpilot]

I am considering the purchase of the C182. It has most of what I want, except it has a non-WAAS Garmin 530. It has a Century 2000 A/P that can couple for ILS approaches. I have my PPL, and will be starting my IR with this airplane. I understand the difference between WAAS and non-WAA. Is a WAAS capable GPS something I will really will wish I had in the next 2-4 years?

 

[gsengle]

I am considering the purchase of the C182. It has most of what I want, except it has a non-WAAS Garmin 530. It has a Century 2000 A/P that can couple for ILS approaches. I have my PPL, and will be starting my IR with this airplane. I understand the difference between WAAS and non-WAA. Is a WAAS capable GPS something I will really will wish I had in the next 2-4 years?

Do you plan to fly low IMC in a single engine airplane with its inherent risks? Do you live somewhere where it is easy if not convenient to divert to a larger airport with an ILS If the weather gets bad, or are you based out of a larger airport with an ILS?

Personally it wouldn’t be a deal breaker, use it to get the price down and then upgrade to a modern GPS unit down the road using some of your savings. Even a 530w is long in the tooth now...

For getting your IR it’s pretty much a non issue.


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[GSDpilot]

Do you plan to fly low IMC in a single engine airplane with its inherent risks? Do you live somewhere where it is easy if not convenient to divert to a larger airport with an ILS If the weather gets bad, or are you based out of a larger airport with an ILS?

Personally it wouldn’t be a deal breaker, use it to get the price down and then upgrade to a modern GPS unit down the road using some of your savings. Even a 530w is long in the tooth now...

For getting your IR it’s pretty much a non issue.


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Home base is KMKC in Kansas City. I will not be flying in tough weather conditions anytime soon. Thanks for the reply, very helpful. I agree with you and price is probably what I am struggling with. The plane is a 1978 C182, with a zero time engine and 5000TT. Clean interior, probably needs paint in the next 3-5 years. Listed at $149k. I offered $135k, and was countered at $142k. This is my first go at ownership, so I am very green to say the least. Broker selling this plane has been very easy to work with, he is just obviously trying to get the most he can. Great mix of excitement and terror all at once. Thanks for the advice!

 

[Radar Contact]

I am considering the purchase of the C182. It has most of what I want, except it has a non-WAAS Garmin 530. It has a Century 2000 A/P that can couple for ILS approaches. I have my PPL, and will be starting my IR with this airplane. I understand the difference between WAAS and non-WAA. Is a WAAS capable GPS something I will really will wish I had in the next 2-4 years?

If the plane checks out good and you’re happy with the final agreed price, I’d buy it. It’s not an absolute must have but I think you’ll find sooner than later that you really want it. At that point, Avidyne has a great trade in deal where you swap the 530 for their IFD540. It’s an easy install and is a tremendous upgrade in single pilot IFR functionality. Whatever you decide, good luck on your airplane shopping!

 

[gsengle]

Yeah can’t help with the plane pricing/negotiation other than that a 182 is a very reasonable first plane choice.... and that they aren’t cheap. Sounds like you’re at a big airport with ILS available so you’re all set.

(My airplane is a Mooney, and for me waas is a must have, but you’ll figure that out over a few years of ownership)


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[bradg33]

The 530 can (probably) be upgraded to a 530W for about $4k (plus labor). Fairly simple job.

I'm based at MKC myself.

 

[Radar Contact]

The 530 can (probably) be upgraded to a 530W for about $4k (plus labor). Fairly simple job.

I'm based at MKC myself.

I believe it’s about 5K now. I did mine 2 years ago (was a mistake for me) and then decided I wanted a new modern navigator and swapped it for the IFD550. To me it was a mistake to put that kind of money to end up with a 20 year old GPS. That being said, it would probably be the cheapest way for him to gain WAAS and the 530s still get the job done. Not sure how long they will be supported though. I’d recommend to the OP to play with the new simulators before making a decision so you make the best choice for yourself.

 

[gsengle]

The 530 can (probably) be upgraded to a 530W for about $4k (plus labor). Fairly simple job.

I'm based at MKC myself.

At this point it would imho be a waste of money, versus a new modern unit like the Avidyne... imho

 

[Bonchie]

At this point it would imho be a waste of money, versus a new modern unit like the Avidyne... imho

Yeah, don't upgrade a 530. Just sell it.

He's gonna need ADSB anyway, so he can sell his transponder as well and get an all in one unit like the GNX375 (GPS, Transponder, and ADSB) or Avidyne's equivalent.

Even on a tight budget, it would make more sense to just buy a standalone WAAS/ADSB unit to meet the mandate. It's very rare that someone "needs" to fly an LPV approach.

 

[Craigd31]

I am considering the purchase of the C182. It has most of what I want, except it has a non-WAAS Garmin 530. It has a Century 2000 A/P that can couple for ILS approaches. I have my PPL, and will be starting my IR with this airplane. I understand the difference between WAAS and non-WAA. Is a WAAS capable GPS something I will really will wish I had in the next 2-4 years?

WAAS will allow a greater range of alternates you can use on the IFR flight plan.

WAAS will also allow you to fly an LPV, which gets you down to or at least close to ILS minimums (usually 200' AGL). This can be handy if a destination airport has no ILS, has an ILS that goes down for repair or if the LOC is operative, but the GS is unusable.

However, when you do get your IR, as a new instrument rated pilot, you probably don't want to go flying to someplace with a forecast of 200' minimums.

 

[midwestpa24]

We usually advise our pilot/owners, that unless you are going to be frequently flying in actual, and flying at or near approach minimums, don't waste the money on WAAS if you have a perfectly good IFR capable GPS already. Truth is, the majority of GA pilot/owners simply don't do it often enough to justify the expense, or to be comfortable and proficient enough to fly in hard IMC safely.

 

[NordicDave]

We usually advise our pilot/owners, that unless you are going to be frequently flying in actual, and flying at or near approach minimums, don't waste the money on WAAS if you have a perfectly good IFR capable GPS already. Truth is, the majority of GA pilot/owners simply don't do it often enough to justify the expense, or to be comfortable and proficient enough to fly in hard IMC safely.

These are good points.

I upgraded my 430 to WaaS for technical reasons. The GNS WAAS versions are getting long term Garmin support, Wanted ADS-B position source and ADS-B Traffic & weather on the panel in addition to the iPad.

Can't imagine flying down to 200' minimums in a single engine airplane, though many do. Just not me. IF engine trouble happens you have to hope when you pop out of the soup you don't hit a barn, house, power lines, etc..

 

[chemgeek]

If you fly IFR you will want WAAS to have LPV availability which will get you lower mins at almost any airport compared to the LNAV approach. At some airports it might be the only game in town. Whether you upgrade the 530 or simply replace it with an Avidyne unit is a personal decision. Non WAAS units will likely go out of support sooner than the WAAS units.

 

[ktup-flyer]

My 430 isn’t waas. Not a big deal in a SEP

 

[chemgeek]

Can't imagine flying down to 200' minimums in a single engine airplane, though many do. Just not me. IF engine trouble happens you have to hope when you pop out of the soup you don't hit a barn, house, power lines, etc..

A proficient IFR pilot should certainly be prepared and capable of flying an approach to 200 minimums. If you can't do this, you are compromising safety. It matters little if the approach mins are 200, 400, or 600 if the engine fails on final in IMC. You are going to have your hands full.

Now, deciding to fly in forecast 200-1/2 weather, say, is a separate question. But weather has a way of not following predictions. So that 800-2 forecast might turn out to be 300-2 at your arrival time, so you need to be prepared to fly to mins. Always.

 

[Ghery]

Go for the 182. Upgrade the panel later if you really feel you need it. Just watch out for a gotcha I've found on the 650 in the panel of the club's 182. It's a touch screen unit and I really hate it in moderately rough air. I really prefer buttons and knobs. Other than that, it works great.

 

[David Megginson]

Can't imagine flying down to 200' minimums in a single engine airplane, though many do. Just not me. IF engine trouble happens you have to hope when you pop out of the soup you don't hit a barn, house, power lines, etc..

That's totally fair—we all have our personal minima. For me, I can't imagine flying VFR into OSH during AirVenture with such crowded airspace, but that's not a problem for many people in this forum.

Your point about engine failure is a good one, but note that even if your destination is easy IFR like 600+2 or 800+3, higher terrain along your route might have cloud/fog right down to the ground, so the same concern applies about an enroute engine failure.

The one positive thing about approaches in single-engine pistons is that things happen very slowly compared to jets or turboprops. When a jet breaks out at 200 ft AGL, they have only a very few seconds before the wheels hit the runway. When you break out at 200 ft AGL in a PA-28 at 90 KIAS and then start decelerating to Vref (say, 65 KIAS), you have close to 30 seconds before touchdown, depending on how long you decide to float down the big runway. Once at DH on an ILS approach into CYYB I saw only the rabbit lights leading up to the runway, not the runway itself, but that was more than enough (legally and practically) to get me to the threshold. It can't have been more than 20-30 seconds before I touched down, but it felt like all the time in the world.

Approaches like that are rare, though; in 16 years of IFR flying, I can probably still count the number of approaches I've done in actual IMC to below 600 ft AGL on my fingers. I'm always hoping for one, just for some extra experience, but they rarely oblige.

 

[455 Bravo Uniform]

Not to be an Avidyne fan-boy, but the buttons of their IFD- series GPS navigators help with the rough air. I’m not IFR rated yet, but even in turbulent VFR, I’ve already noticed the benefit.

 

[David Megginson]

Not to be an Avidyne fan-boy, but the buttons of their IFD- series GPS navigators help with the rough air. I’m not IFR rated yet, but even in turbulent VFR, I’ve already noticed the benefit.

Glad it's working for you—IFDs are great units. A couple of extra points to add, though, just for clarification:

1. You can do a lot more with knobs and buttons on the GTN units than the Avidyne advocates let on (for example, tuning and switching frequencies, selecting and activating a direct-to-waypoint, etc. etc.). It's not remotely a touchscreen-only unit, though it doesn't have as many physical button options as the IFD.

2. Using either buttons/knobs or a touchscreen in turbulence is tricky, and it would be good if we taught pilots to use a proper two-part movement for either: first brace your pinky and ring finger on the panel or radio, then use your thumb and index finger to push a button, turn a knob, or select something on a touchscreen.

Knobs and buttons let you get away with stab and grab approach in turbulence sometimes, but you're a. likely to miss your target a lot (at least I do with my older radios), and b. you're putting a huge and unnecessary strain on the knobs, because once you grab them, you're using them to stabilise your whole arm.

 

[brcase]

Agree with get you instrument rating and see how much you actually use it. I doubt you will fly in conditions where you wished you had LPV approaches available much or even ever in the 182.
The 530 is a great GPS and will do 99% of what you want a GPS to do.

Brian
CFIIG/ASEL

 

[David Megginson]

Agree with get you instrument rating and see how much you actually use it. I doubt you will fly in conditions where you wished you had LPV approaches available much or even ever in the 182.
The 530 is a great GPS and will do 99% of what you want a GPS to do.

Brian
CFIIG/ASEL

I missed the start of the thread. If the OP already has a 530, great -- stick with it! If not, don't pay thousands of dollars for tech that's starting out 20 years old at installation time. With low prices for new units these days, buying a used 430 or 530 just doesn't make sense. They still have some good years ahead, but the majority of their useful life is behind them (a lot like many of us private pilots, come to think of it).

 

[wilkersk]

WAAS will allow a greater range of alternates you can use on the IFR flight plan....

Huh? Did this change?

AIM 1-1-19.g:NOTE- Any required alternate airport must have an approved instrument approach procedure other than GPS that is anticipated to be operational and available at the estimated time of arrival, and which the aircraft is equipped to fly.

 

[wilkersk]

I am considering the purchase of the C182. It has most of what I want, except it has a non-WAAS Garmin 530. It has a Century 2000 A/P that can couple for ILS approaches. I have my PPL, and will be starting my IR with this airplane. I understand the difference between WAAS and non-WAA. Is a WAAS capable GPS something I will really will wish I had in the next 2-4 years?

You need a WAAS position source for ADS-B out. But, there are plenty of cheaper ways to get that.

 

[John Myers]

Huh? Did this change?

AIM 1-1-18 c. 9(a):

Pilots with WAAS receivers may flight plan to use any instrument approach procedure authorized for use with their WAAS avionics as the planned approach at a required alternate, with the following restrictions. When using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV or circling minima line, or minima on a GPS approach procedure, or conventional approach procedure with “or GPS” in the title.

 

[Jim_CAK]

I believe it’s about 5K now. I did mine 2 years ago (was a mistake for me) and then decided I wanted a new modern navigator and swapped it for the IFD550. To me it was a mistake to put that kind of money to end up with a 20 year old GPS. That being said, it would probably be the cheapest way for him to gain WAAS and the 530s still get the job done. Not sure how long they will be supported though. I’d recommend to the OP to play with the new simulators before making a decision so you make the best choice for yourself.

I would also suggest you think about putting a lot of money in an old GPS. We had a 20 year old 430 non WAAS. We looked at the cost of the WAAS upgrade last year and opted to go with a new Avidyne 440. After a year with the new GPS I am glad we did not put money in old unit. The Avidynes slide into the same tray as the GNS units. It keeps the install cost down. We also sold the GNS 430 to offset the cost of the new unit. I just did not want to put that kind of money in a 20 year old box. I just did an IPC today with Avidyne and really like the unit. Regardless of the unit - once you have WAAS you will really like those LPV approaches.

 

[455 Bravo Uniform]

The downside of the Avidyne? There are too many ways to do the same thing and it’s hard to come up with a system. Wierd but true, for me.

 

[David Megginson]

The downside of the Avidyne? There are too many ways to do the same thing and it’s hard to come up with a system. Wierd but true, for me.

That's not weird—it's actually a basic design principle. There's a classic web-design book on the same topic called Don't make me think!.

Too many options and too much information can lead to worse outcomes, especially in an environment where distraction can be deadly. Unfortunately, vendors compete on features, and no one's innocent of interface overload.

 

[Brad Z]

FWIW, the upgrade replaces most of the guts of the unit, so there are benefits in extending the life of the unit.

What really irks me is that Garmin was initially upgrading these units for $1,500 (plus the cost of the new antenna and wiring if necessary). Scores of cheap azz pilots decided it was too much money and never bothered to upgrade, even though the WAAS upgrade returned more than 100% of the cost at time of resale.

I did my upgrade about 7 years ago at $3k and didn't regret it one bit. To me the functionality and terrain data was worth it.

 

[NordicDave]

A proficient IFR pilot should certainly be prepared and capable of flying an approach to 200 minimums. If you can't do this, you are compromising safety. It matters little if the approach mins are 200, 400, or 600 if the engine fails on final in IMC. You are going to have your hands full.

Now, deciding to fly in forecast 200-1/2 weather, say, is a separate question. But weather has a way of not following predictions. So that 800-2 forecast might turn out to be 300-2 at your arrival time, so you need to be prepared to fly to mins. Always.

Agree with your post. If I know minimums are 200-1/2 for the flight I'll usually look for alternatives. Weather does change and stuff does happen. It's nice to have the capability.

 

[gsengle]

Agree with your post. If I know minimums are 200-1/2 for the flight I'll usually look for alternatives. Weather does change and stuff does happen. It's nice to have the capability.

And a legit alternate is an airport with an ILS...


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[David Megginson]

Agree with your post. If I know minimums are 200-1/2 for the flight I'll usually look for alternatives. Weather does change and stuff does happen. It's nice to have the capability.

My personal limit is that my main destination (or a nearby airport) is forecast to meet alternate minima when I depart: e.g., if I'm flying to an airport with two usable precision approaches, I want the forecast to show at least 400+1.

That doesn't guarantee that it won't be worse when I arrive, but it gives a bit of a margin. If I take off when the forecast is already 200+½, then there's zero wiggle room.

 

[gsengle]

I fly twins where I regularly go as low as 1800 rvr indefinite ceiling, but my personal limit in a single, driven by having one engine not by pilot skill, is widespread ceilings below 1000agl. Why? Because risk management can be well summarized as never being one failure away from oblivion - such as a single engine failure in a single in low IMC. Just my approach, but a sound one I think. If you need more convincing listen to this atc tape...

https://forums.liveatc.net/atcaviation-audio-clips/bonanza-5626d-crash-plainville-ma-2015-06-28/


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[Clip4]

FWIW, the upgrade replaces most of the guts of the unit, so there are benefits in extending the life of the unit.

What really irks me is that Garmin was initially upgrading these units for $1,500 (plus the cost of the new antenna and wiring if necessary). Scores of cheap azz pilots decided it was too much money and never bothered to upgrade, even though the WAAS upgrade returned more than 100% of the cost at time of resale.

I did my upgrade about 7 years ago at $3k and didn't regret it one bit. To me the functionality and terrain data was worth it.

If you remember, the WAAS update was delayed by Gamin several times. To limit their loses they required owners to sign up for the upgrade during a short window prior to its release to maintain the $1500 price and when the upgrade was released there was a short period of time to get it done.

 

[Clip4]

I fly twins where I regularly go as low as 1800 rvr indefinite ceiling, but my personal limit in a single, driven by having one engine not by pilot skill, is widespread ceilings below 1000agl. Why? Because risk management can be well summarized as never being one failure away from oblivion - such as a single engine failure in a single in low IMC. Just my approach, but a sound one I think. If you need more convincing listen to this atc tape...

https://forums.liveatc.net/atcaviation-audio-clips/bonanza-5626d-crash-plainville-ma-2015-06-28/


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even IFR in severe clear isn’t safe in an SEL. http://www.kathrynsreport.com/2016/01/beech-b36tc-bonanza-fatal-accident.html

 

[David Megginson]

even IFR in severe clear isn’t safe in an SEL. http://www.kathrynsreport.com/2016/01/beech-b36tc-bonanza-fatal-accident.html

No flying is safe, especially not with piston engines—the best we can hope for is safe enough. The last time I saw the stats, the extra engine on twins was producing slightly worse safety outcomes—it was more likely to hurt you in a Vmc rollover than to save you from a forced landing over obscured or inhospitable terrain.

But there are lots of other reasons to fly a twin (FIKI, bigger load, higher ceiling, etc etc). Unfortunately, unless the stats have improved recently, enhanced safety isn't (yet) on that list.

 

[Radar Contact]

The last time I saw the stats, the extra engine on twins was producing slightly worse safety outcomes—it was more likely to hurt you in a Vmc rollover than to save you from a forced landing over obscured or inhospitable terrain.

In my opinion this gets unfairly talked about in the aviation circles and regurgitated as truth. As a member on the Twin Cessna Owners forum I can tell you of several instances where owners have recently been forced to cage one and landed safely. This never gets reported. If these are never reported then how could any statistics on this topic be relevant/accurate? Don’t get me wrong, training and proficiency are of utmost importance and the second engine is far from a guarantee...just don’t think there are accurate stats on this subject. If my memory is correct, I think @Lance F caged one not too long ago and he’s still with us.

 

[gsengle]

No flying is safe, especially not with piston engines—the best we can hope for is safe enough. The last time I saw the stats, the extra engine on twins was producing slightly worse safety outcomes—it was more likely to hurt you in a Vmc rollover than to save you from a forced landing over obscured or inhospitable terrain.

But there are lots of other reasons to fly a twin (FIKI, bigger load, higher ceiling, etc etc). Unfortunately, unless the stats have improved recently, enhanced safety isn't (yet) on that list.

But your outcomes specifically when flying low ifr with one engine failed are WAY better in a twin...


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[David Megginson]

But your outcomes specifically when flying low ifr with one engine failed are WAY better in a twin...


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Do we have stats about that fatal outcomes after a low-altitude engine failure in IMC for twins vs singles, or is that an hypothesis?

 

[gsengle]

Do we have stats about that fatal outcomes after a low-altitude engine failure in IMC for twins vs singles, or is that an hypothesis?

One you crash and one you don’t. Listen to that atc tape I posted.


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[David Megginson]

In my opinion this gets unfairly talked about in the aviation circles and regurgitated as truth. As a member on the Twin Cessna Owners forum I can tell you of several instances where owners have recently been forced to cage one and landed safely. This never gets reported. If these are never reported then how could any statistics on this topic be relevant/accurate? Don’t get me wrong, training and proficiency are of utmost importance and the second engine is far from a guarantee...just don’t think there are accurate stats on this subject. If my memory is correct, I think @Lance F caged one not too long ago and he’s still with us.

That's because non-accidents don't get reported, for singles or twins; it's just the number of fatal accidents for hours flown.

I don't know if that's improved in recent years for twins, but if you want to consider individual reports of successful landings in twins after an engine failure (the majority, I'd hope), you also have to consider that a twin is roughly 2× as likely to have an engine failure as a single is, so they'll have a lot more need to handle them.

I completely understand that there are lots of good reasons for having a twin. I just haven't personally seen the evidence yet (stats, not personal stories) that safety is one of them.