GFC 500 autopilot: down the rabbit hole.

[EchoMax]

I have a 1966 M20E with a functional STEC-50 with Alt-hold.  Nevertheless, I have a hankering for a modern autopilot.

The decision tree starts out simply enough:  there is only one AP available at this time for the E, the Garmin GFC 500.  It's a reasonably priced, reportedly excellent AP.  So far, so good, but then we go down the rabbit hole.

The Aspen won't drive the GFC 500.  Will it be of any use?  Should I remove it?

I'll need a G5 to drive the GFC 500.  But hey!  The GI 275 is only a little more and is much better so let's make that a GI 275.

Now I'll need a backup for IFR, so add a backup G5.  Oh, what the heck!  Let's just make that two GI 275s.

But don't two GI 275s present a possible single-point failure, as has been recently discussed?  So maybe I should keep the vacuum AI.  Or if I want to ditch the vacuum system, I could convert the step from vacuum to electric and add a Lifesaver electric attitude indicator.

(Oh, and while we're at it, let's upgrade the GTN 750 to the 750xi.)

Have I left anything out?  What would you do?

Standing pat may ultimately prove to be the best option; it is certainly the most cost-effective.  But that would make for a rather dull discussion.

Tom-

 

My current panel includes:

STEC 50 w Alt Hld
Stormscope - WX-900
Aspen PFD 1000 MAX
GTN 750
FS 510
JPI 930
GDL 88
GPS 696
GMA 340
GTX 327
CYA100 AOA
 

[KB4]

Since I am spending yours, G3X backup G5 and GFC500 and 255 Nav/com

[V1VRV2]

No need for 2 GI275’s  1 GI275 will display everything you need. 

[Skates97]

Get rid of the vacuum system. Put the electric step in, it is great. The RCA 2610-3 makes an excellent replacement for your turn coordinator and you now have a backup AI with battery backup.

I don't have anything to compare the GFC500 to, but I have been thoroughly impressed by it and am glad I spent the money on it.

[EchoMax]

1 hour ago, KB4 said:

Since I am spending yours, G3X backup G5 and GFC500 and 255 Nav/com

Please forgive my ignorant questions:  I'm here to learn.

1.  What is the advantage of the G3X/G5 combo vs two GI 275s?

2.  I have a  perfectly good (but old) KX 155 Nav/com.  What would be the advantage of the Garmin 255 Nav/com?

[ZuluZulu]

G3X Touch.  Go big or go home!

[PT20J]

10 minutes ago, EchoMax said:

Please forgive my ignorant questions:  I'm here to learn.

1.  What is the advantage of the G3X/G5 combo vs two GI 275s?

2.  I have a  perfectly good (but old) KX 155 Nav/com.  What would be the advantage of the Garmin 255 Nav/com?

The G3X Touch with the 10" display can be set to split screen so you get a PFD and MFD in a single display. You have a JPI 930 but if you didn't (or wanted to replace it) you can get the EIS option for an engine monitor. The G3X/G5/GFC 500 combination were really designed to work together. If the G3X fails, the G5 will still operate the autopilot.

KX 155s are still serviceable, but the displays are no longer available and sooner or later it will get difficult to keep working. The 255 has a database that allows you to look up frequencies by identifier.

In my case, I just wanted a reliable airplane for the next ten years. I decided to go with a G3X Touch with EIS, G5, GFC 500, PMA450B, GTN 650Xi, GNC 255A, GTX 345. I already had the GTX 345 but everything else is new. That's how a "cheap" autopilot turned into an $80K (installed) upgrade.

Skip

[Mooney Dog]

I would say this depends on how much money you want to spend. Personally. I think your AP would be fine, but if you're dying to upgrade, do it in a way you're happy with it.

 

I personally have just installed dual G5s in prep for a gfc500. I personally dont care fo the gi275, though it IS a better unit. If i had a lot of money to play with, i would have gone G3 / g3x system. 

 

If you do a lot of IFR flying, upgrading to the flight stream may be more worth it than getting the 750xi. You could also forgot the gfc500 and get a avidyne dfc90 which runs off the aspen.  

Edited September 16, 2021 by Mooney Dog

[ArtVandelay]

If you do a lot of IFR flying, upgrading to the flight stream may be more worth it than getting the 750xi. You could also forgot the gfc500 and get a avidyne dfc90 which runs off the aspen. 

Since when is the dfc90 approved for Mooneys?

[Mooney Dog]

Just now, ArtVandelay said:

Since when is the dfc90 approved for Mooneys?

Doh, i should have checked that. 

[carusoam]

9 hours ago, EchoMax said:

I have a 1966 M20E with a functional STEC-50 with Alt-hold.  Nevertheless, I have a hankering for a modern autopilot.

Wait a second…. Tom…

Don’t you own The 1966 M20E aka Gypsy Rose?

 

You probably want to look at pictures…. Of what people have been installing lately…

There is a video of an Ovation doing approaches around here this week… Using a pair of GI275s…

There is a video of an M20C posted weekly with a pair of Dynon big screens….

Installation is important to understand… there is a story posted around here where two instruments were expected to back up each other… when one failed… the other provided no back up….  Something got lost in the purchase and installation…. The new owner was un-aware of the missing link… two identical looking instruments may or may not have come with the required skills to be a back-up instrument…  so many options to check.

 

The G3X is getting installed quite regularly around here… looks great.

Some people prefer the strengths of the G500txi for a few AMU more…

Getting a second screen for the EIS is often considered… but a JPI 930 is still pretty powerful…

Many people keep adding screens to their Aspen unit count… going with the Max seemed to be popular a couple years ago…

Holy cow… computer speeds are important… all the displays are handling a ton of data…. Even the newer GTN750TXi is More powerful than the prior non-txi version…

Sticking with one brand does a good job of maintaining interoperability….

There have been dozens of GFC500s installed in a wide variety of Mooneys around here lately…

There are about 5 Mooneys with really nice Dynons in them with an empty space waiting for the DFC approval to come in….  Dynon is pretty good with their new product deliveries… but not quite as good as Garmin has been…  miles ahead of that Bk brand….

 

Remember… Rose deserves the best!   

Go M20E!

Best regards,

-a-

[carusoam]

Update your back-up strategy…

The spare AI can be swapped with a G5 to run the GFC500…

If it’s a vac instrument, you won’t miss it…

+1 on spending OPM! 

Best regards,

-a-

[1980Mooney]

So if I understand the "rabbit hole" proposition:

• You have a well equipped Mooney that is a very capable and stable IFR platform
  • With autopilot, alt hold, digital PFD, GPSS, Flightstream etc.
  • Everything works perfectly
  • You contemplate spending $30-40K - maybe you save a few dollars salvaging the old units
• The result is that you will have a well equipped Mooney that is a very capable and stable IFR platform

OK so you trade a rate based autopilot for an attitude based unit.  You will be able to touch one of the screens with your finger.  And you can get stability protection and Smart Glide which you don't mention so it is not clear if it is any value to you.  Going all Garmin may play better together and have a smoother upgrade path over time.  And the new equipment may reduce maintenance cost (but there are a lot of comments on MS and others about the Garmin servos being weak and may not go the distance). But basically it seems like a slicker version of what you have with the same capability plus a couple bells and whistles.

• Has the S-Tec or any of the other components failed you or restricted you from making a mission that you desired?
• Will the new set-up allow you to do things or make missions that were never before possible?
• Will you be able to fly in weather or instrument conditions not previously possible?

From a monetary standpoint you are contemplating adding upgrades that could be close to 50% of the current value of a 55 year old plane.  If you add $40k of avionics upgrades to a $80K plane will you be able to sell it for $120K?....no.  Will it be worth $90k?....probably.  Will it be worth $100k?....maybe someone will pay.  Perhaps half of the upgrade cost is unrecoverable - in the short term you can't get it back and in the long term Garmin will have new equipment out making the GTN750xi as obsolete as the GTN750 you replaced so you still won't get it back.

The previous comments by carusoam above reminds me that avionics are becoming like iPhones or Samsung Galaxy's - it's all about screen size and processor speed.  An iPhone 8 works just as well as an iPhone 12 for 98% of the tasks.  They run the same apps.  And today comes the 13 which Apple hopes you will pay a premium for a modest improvement.  It becomes a treadmill of spending.

But if the unrecoverable 50% investment produces value in your eyes then spend it - Garmin and your avionics shop will be happy too.

 

Edited September 17, 2021 by 1980Mooney

[EchoMax]

10 hours ago, carusoam said:

Wait a second…. Tom…

Don’t you own The 1966 M20E aka Gypsy Rose?

 

'Tis true, and I love her like my wife, though they're both getting kind of old.

9 hours ago, 1980Mooney said:

So if I understand the "rabbit hole" proposition:

• You have a well equipped Mooney that is a very capable and stable IFR platform
  • With autopilot, alt hold, digital PFD, GPSS, Flightstream etc.
  • Everything works perfectly
  • You contemplate spending $30-40K - maybe you save a few dollars salvaging the old units
• The result is that you will have a well equipped Mooney that is a very capable and stable IFR platform

Exactly so.  1980Mooney, you have really nailed it!  Your reasoning is clear, logical, and convincing:  I should wait until the STEC-50 fails, and then and only then, upgrade the AP.  That keeps me from falling down a 30 AMU rabbit hole, at least for now.

Still, it's fun to dream, and window shopping is free (like spending OPM).

Should I swap out the Garmin GMA 340 audio panel for the PS Engineering PMA450B?

What about upgrading the Garmin GTN 750 to 750xi? 

Gypsy needs some new rings on her fingers and bells on her toes, but maybe not a new autopilot at this time.

T-

[kpaul]

11 hours ago, 1980Mooney said:

If you add $40k of avionics upgrades to a $80K plane will you be able to sell it for $120K?....no.  Will it be worth $90k?....probably.  Will it be worth $100k?....maybe someone will pay.

He bought the late Bob Belville's E.  It is worth north of 100K already, and sold close to the number you claim is unsellabe.  Now, will it sell for $160K after another 40K of avionics gets added, probably not.

[Will.iam]

Does the plane already have all led lighting? If not spend some money there, at least you get 10k hours of bulb life and it’s lighter giving you some useful load back. Maybe get a ceramic coating to help protect the paint.  

[ArtVandelay]

Exactly so.  1980Mooney, you have really nailed it!  Your reasoning is clear, logical, and convincing:  I should wait until the STEC-50 fails, and then and only then, upgrade the AP.  That keeps me from falling down a 30 AMU rabbit hole, at least for now.

As others will upgrade, you’ll have plenty of used stec 50 parts become available, buy them and you’ll have cheap parts available on the shelf.