GFC500- It's here!!!

[81X]

It's here!  A functional GFC500 in my Mooney 231 that I got to fly behind today!   I wanted to share my first impressions on the new AP, although I will likely be adding on after this weekend (read more flight time).

Before it went in, my 231 was equipped with a KFC150 with altitude preselect and VS mode which was tied into my G5 HSI and GTN750- no slouch of a setup to begin with.  As such, my comparison baseline is against the KFC150.  

Today was a great day for playing- CAVU, nice and bumpy below 5000 or so and then smooth above.  I flew it about 2 hours, mostly dropping the test pilot off at CLT to get home. (He's a MS-er, so he's A-OK in my book) We were able to do some maneuvers, demonstrations and approaches.  

First off, the ergonomics and annunciations on the AP control panel and the G5 are intuitive and took about 30 minutes to get used to.  Button press pressure is just right- not too hard, but not too soft for turbulence.  The annunciator colors on the G5 are also pretty intuitive. 

I really liked the TOGA feature- you're all set for a wings-level climb right out of the get go.  Preselecting the heading, altitude bug and VS are simple and get you set up for a nice instrument departure should you need it.  I unfortunately forgot to test the coupled go around- one of the things I was super excited for, more to come on that.  

The VS mode is so good at holding rate it's scary, even in turbulence.  IAS climbs in turbulence were OK as the pitch hunted for airspeed a little, but was awesome in the smooth air above.  I'm sure I'll find it immensely useful in the summer when wanting to keep the engine cool in the climb- it's HOT in SC.  1,000 and 200 foot alerts are standard and really nice; you can also set the bug to minimums on an approach and it will aurally and visually alert you- yes, basic but still nice.  Altitude hold?  None of this 10 -20 feet off BS.  It holds right on the money even in turbulence- it's digital after all and computers are binary.  I didn't get to play with VNAV yet unfortunately.  

For lateral guidance, the heading mode exhibits smooth and consistent rates in addition to very good rolls in/out of turns.  Nav mode tied to a GPS?  Native GPSS?  Yep.  intercepts and course holding is where you would expect it- rock solid and on point.  in turbulence, the roll axis doesn't wallow all over the place like a rate-based AP, that thing is rock solid like the 150 was- a very comfortable ride in bumps.  

ESP- I got to try out the envelope protection in the areas of of slow speed and over-bank angle.  the stall protection is very cool as you can really feel it pushing the stick below about 70 kts or so, just as the stall beeper is going off.  Steep turns are my jam; and cranking it over on a wing, it starts engaging at 45 degrees and is really fighting you at 50 degrees to get to a more reasonable angle- again kind of useful for those IFR hand flying distractions.  Unfortunately it won't save you from an accelerated stall- so you need to continue watching your airspeed base-final.  I think LVL mode also belongs in here- I was in a descending (or maybe ascending, I don't exactly recall) turn and I hit the LVL button- that AP meant business getting the airplane back to straight and level.  It was a little uncomfortable, but hey, if you're hitting that button, you're likely in a jam and probably need aggressive responses.  

Approaches- I messed up the AP on the approach to GMU by hitting the AP key instead of APR key (dummy) but after realizing it (or maybe being nudged by the test pilot, whatever), I was able to re-engage the AP on approach and the AP recaptured the GS- Nice!  CLT gave us a visual approach, so we loaded the 36R visual into the 750, and oh yes of course the AP can capture and couple like an ILS- kind of fun!  I ran a real ILS back at my home drome and gave it a nice 70 degree intercept about a half mile from the localizer at 140 kts- only slightly overshot the localizer (less than a dot) but intercepted it and stayed rock solid down to minimums.   

My favorite feature that I didn't think I would ever value- the Yaw Damper.  Today's turbulence (not too bad but still there down low) was a good test.  I could not believe how much it smoothed things out.  We induced some yaw oscillations and hit the YD just as the ball was in the cage- Boom; dead stopped.  On my descent back home I tried YD on and off and when the bumps came- it was a big difference.  

Overall, I'm very impressed.  The biggest shortcoming to me is that the airplane didn't come back with a G3X.  

Lastly and as a side note, the Garmin team and products are first rate, but you all probably knew that.  Working with the people there was a really good experience.  Yes, there were delays which was annoying, but they were all more or less because of the need to redesign some stuff (brackets, sprockets, etc.) to get it right- something that we all can appreciate in the long run.  

 

 

[Frank Mooney]

If you have an "in" with the Garmin folks tell them to hurry i'm ready!! 

[carusoam]

The new phone books are here! - Nathan Johnson.

 

Great pirep, 81X!  

That sounds pretty exciting.  The new technology in the market is really hitting the mark.

thanks for sharing the details.

Does the old KFC150 get sold? Was it taken in on a trade? Or does it go on a shelf in a hangar?  Wondering how good it’s value is...

Best regards,

-a-

[81X]

@carusoam,   My KFC150 computer, VS/preselect, and 256 FD/AH will be available for sale in the next week or two to help get someone by until they can get themselves a GFC500.    I’ll give the MS community first shot in the classified section before eBay. 

[INA201]

Thanks for the PIREP.

I had a ride in a Cirrus with the Garmin AP and was also extremely impressed with the yaw dampener.  I would definitely consider buying it with the dampener if it’s not too much. It makes for an extremely smooth ride especially with non aviator passengers. 

[ArtVandelay]

2 minutes ago, INA201 said:

Thanks for the PIREP.

I had a ride in a Cirrus with the Garmin AP and was also extremely impressed with the yaw dampener.  I would definitely consider buying it with the dampener if it’s not too much. It makes for an extremely smooth ride especially with non aviator passengers. 

I’ve never noticed my tail wagging in the Mooney?

[khedrei]

I'm curious about the VNAV. In Garmins video/sales pitch on it way back they said the VNAV is for future expansion/options. So yours works and is fully functional? Next I would ask what exactly is the VNAV capability? I'm under the impression a VNAV capability will allow you to follow virtical climb and decent profiles to meet altitude xing restrictions on SIDS or STARS or ones given by ATC. Am I misunderstanding this? In essence, allows the enroute portion to have veritical guidance as opposed to coupling to an LPV approach and having that be the only vertical guidance it is capable of. 

[johncuyle]

23 minutes ago, ArtVandelay said:

I’ve never noticed my tail wagging in the Mooney?

It's not bad, but I notice it in my K model.  I never noticed it when flying J models but I only have about 30 hours in them.  Then again, I noticed it the second flight I took in the K.  Maybe the K is a bit more susceptible to it than other models due to the CG tending to be farther forward?

Edit for 81X:  If Garmin asks, tell them you may have sold a yaw damper add-on to a different K owner.

[carusoam]

Tail wagging is definitely a geometry challenge...

1) distance between Cg and tail....

2) size of the vertical component of the tail...

3) The short body can have some waggle, the LB requires a larger force to have a waggle...

4) Brand B’s V tail doesn’t have a nice luxurious Tail like a Mooney does...  waggles in rhythm...

5) Brand Ci... So blaaaah.... the least bit of waggle everyone would be sleeping.... 

6) For the K... take note of how effective the tail is as the air gets thinner... that vertical component becomes less effective as the air thins... smooth air at altitude gives less funky bumps... perturbation?

7) Hard to eliminate perturbances, But a damper can actively minimize them...

PP thoughts only...

Best regards,

-a-

[flyingcheesehead]

1 hour ago, khedrei said:

I'm curious about the VNAV. In Garmins video/sales pitch on it way back they said the VNAV is for future expansion/options. So yours works and is fully functional? Next I would ask what exactly is the VNAV capability? I'm under the impression a VNAV capability will allow you to follow virtical climb and decent profiles to meet altitude xing restrictions on SIDS or STARS or ones given by ATC. Am I misunderstanding this? In essence, allows the enroute portion to have veritical guidance as opposed to coupling to an LPV approach and having that be the only vertical guidance it is capable of. 

You're correct about what VNAV is. If you have a G5 or G3X Touch *and* a Garmin GTN 650/750 with software version 6.50 or later (which is when they added VNAV to the GTN), then you should have VNAV capability with the GFC 500.

[81X]

3 hours ago, khedrei said:

I'm curious about the VNAV. In Garmins video/sales pitch on it way back they said the VNAV is for future expansion/options. So yours works and is fully functional? Next I would ask what exactly is the VNAV capability? I'm under the impression a VNAV capability will allow you to follow virtical climb and decent profiles to meet altitude xing restrictions on SIDS or STARS or ones given by ATC. Am I misunderstanding this? In essence, allows the enroute portion to have veritical guidance as opposed to coupling to an LPV approach and having that be the only vertical guidance it is capable of. 

I’m going to explore (try for the first time) VNAV some this weekend but I think it’s going to be most useful for nonprecision type full procedure approaches or the step downs on complex GPS approaches.  

My VCALC in the GTN utilities section has been replaced with VNAV as the software on my 750 was updated while at Garmin, at least that’s my observation from my 20 seconds of messing around with that mode yesterday. 

[81X]

1 hour ago, Hyett6420 said:

Great pirep, thank you.  Nice to hear the real,effects of this baby rather than the sales beochures and armchair experts.

does the gfc500 only link to G5s or can you run it off a aspen and avidyne combo?

 

It’s the real deal for full function  autopilot.  I like armchar/hangar flying and theory as much as the next pilot, but I like actually flying more!  

 

To answer your question, I think it needs a Garmin attitude source, likely as a part of the STC but I’m not sure about that now or for future options; that’s a question for Garmin to answer. 

 

Edited March 28, 2019 by 81X

[flyingcheesehead]

3 hours ago, Hyett6420 said:

Great pirep, thank you.  Nice to hear the real,effects of this baby rather than the sales beochures and armchair experts.

does the gfc500 only link to G5s or can you run it off a aspen and avidyne combo?

It needs either the G5 or the G3X Touch - But it's not just Garmin trying to exclude everyone else, it's actually an integral part of the system, and also the reason why you must have a G5 to be able to use the GFC500 with the G500 TXi.

You can kind of think of the G5/G3X as the attitude source, similar to how I have to have a KI-256 for my KFC-150.

However, that analogy isn't great in this case. For the KFC-150, I have the KC-192 computer that has the buttons on it and the brains in it. It gets fed attitude, heading, course deviation, etc and outputs signals to drive the servos and flight director.

In the case of the GFC 500, it's a *system*. It's a fully digital autopilot. Even the servos have brains! The GFC 500 uses CAN bus for the various bits to communicate with each other. And, unlike older autopilots like the King with its KFC 192 computer, the control unit in the panel, the GMC 507 mode controller is NOT computing anything - It's merely sending messages to the other parts of the system like "Hey guys, the pilot would like to enable VNAV mode!"

Most of the brains of the system actually lies in software for the G5 and G3X touch. In the experimental world, the predecessor to the GFC 500 was simply a G3X Touch with three servos - The mode controller was completely optional. Today, with the GFC 500 you will have the mode controller, but you can also have some control from the G5 and the G3X Touch. So, for example, if you're climbing out in VS or IAS mode on the GFC 500, and you set the altitude bug for an altitude above you, it will automatically arm the altitude preselect and capture that altitude without you touching the "ALT" button on the mode controller.

The most visible, and to me coolest, manifestation of how this works is in the failure/backup modes for a G3X/G5/GFC500 combo. You could set up the scenario I talked about above, punching IAS on the GMC 507, setting an altitude bug on the G3X, and then have BOTH of those units fail, and the G5 will still maintain IAS and capture the altitude you had previously selected on the now-failed G3X! 

So, that's also why the G500 TXi alone can't drive the GFC 500. The TXi doesn't use the CAN bus, so when you have that system installed, what's really happening is the TXi is telling the G5 what to do, and the G5 is actually executing it. In a TXi + G5 + GFC 500 combo, if the G5 goes down, you lose the autopilot as well.

I know that was a long answer, but hopefully worthwhile. 

[aviatoreb]

I wonder why, if the G5 is so fully a central part of the GFC500 computer, the brains of the computer, then why we need two boxes.

Why couldn't they have built a G5+GFC500 computer into one box, roughly the size of the g5, to fit into the attitude indicator position - or maybe think of it as a gfc500 computer with a built in attitude indicator to go in the place where your g5 goes.  One box.

[MIm20c]

10 minutes ago, aviatoreb said:

I wonder why, if the G5 is so fully a central part of the GFC500 computer, the brains of the computer, then why we need two boxes.

Why couldn't they have built a G5+GFC500 computer into one box, roughly the size of the g5, to fit into the attitude indicator position - or maybe think of it as a gfc500 computer with a built in attitude indicator to go in the place where your g5 goes.  One box.

The g5 is an all in one box AP controller. Nothing else is needed for experimental aircraft. The control box is added to help input heading, VS, etc. 

[flyingcheesehead]

21 minutes ago, aviatoreb said:

I wonder why, if the G5 is so fully a central part of the GFC500 computer, the brains of the computer, then why we need two boxes.

Why couldn't they have built a G5+GFC500 computer into one box, roughly the size of the g5, to fit into the attitude indicator position - or maybe think of it as a gfc500 computer with a built in attitude indicator to go in the place where your g5 goes.  One box.

That's exactly what the G5 already is! The GMC 507 isn't technically required for the GFC 500 to work.

I'm guessing the reason it's part of the STC version is something to do with some obscure reg... Or maybe it was easier to certify with the controller and Garmin figured most of us would want it anyway, based on what the experimental crowd did.

[aviatoreb]

1 hour ago, MIm20c said:

The g5 is an all in one box AP controller. Nothing else is needed for experimental aircraft. The control box is added to help input heading, VS, etc. 

Huh - so its just buttons?

[flyingcheesehead]

10 minutes ago, aviatoreb said:

Huh - so its just buttons?

Yep. Buttons and knobs is all it is, it's the G5 or G3X touch that actually has most of the brains. In experimental installations, the mode controller isn't required. The first time I saw it, it was just the G3X Touch and servos.

That's why the failure modes are so friendly if you have both a G3X Touch *and* a G5: Your autopilot has two brains! And neither one is really in control, they're both just part of a system, so it doesn't even hiccup if you lose one.

[toto]

4 minutes ago, aviatoreb said:

Huh - so its just buttons?

For what it's worth, several of the functions are available directly on the G5, including heading and altitude preselect. Disabling the envelope protection can only be done from the G5, afaict, but setting the vertical speed can only be done from the 507. 

The 507 itself is very thin, about a half inch of plastic that's screwed into the panel with a bunch of buttons, a couple knobs, and a rotary thing. I have no idea how much logic actually lives in that box, but I'm sure that @flyingcheesehead is right (i.e., none at all - it's just an interface).

[Bob - S50]

11 hours ago, khedrei said:

I'm curious about the VNAV. In Garmins video/sales pitch on it way back they said the VNAV is for future expansion/options. So yours works and is fully functional? Next I would ask what exactly is the VNAV capability? I'm under the impression a VNAV capability will allow you to follow virtical climb and decent profiles to meet altitude xing restrictions on SIDS or STARS or ones given by ATC. Am I misunderstanding this? In essence, allows the enroute portion to have veritical guidance as opposed to coupling to an LPV approach and having that be the only vertical guidance it is capable of. 

You almost got that right.  The GTN/GFC VNAV only works for descents, not climbs.

You can also make up your own crossing restrictions.  So for example, when coming back to the Seattle area, with a little pre-flight planning I can set up some crossing restrictions to keep me below the Class B.  And you can also set a default rate or angle of descent.  I plan to set ours to 1.89 degrees which is 200'/NM.  That works out to be 500 fpm at 150 knots GS.

And the VNAV can guide you down to the point where you intercept the LPV or ILS glidepath, all while you watch.

[Dan208]

This looks amazing.  Great pirep.  

[Bob - S50]

I actually have a question.  Reading the manual, if the autopilot is off, you have climbed above 500 AGL and are still at least 200 AGL, if the speed drops below 80 KIAS, the ESP is supposed to kick in and lower the nose to increase the speed.

So my question is, have you tried flying an LPV or ILS and used a speed below 80 KIAS on final?  Will the AP do that?  If the AP is off and you are using the FD, will it allow you to drop below 80?  Or will we have to maintain 80 KIAS on final until we are below 200 AGL unless we disable ESP?

[bradp]

Another question. Apparently a GPS signal is required to perform VOR/ localizer / ILS approaches or to track a Nav course   

If the signal from the primary navigator is disrupted is the signal from the G5 sufficient to provide that aiding?  In the case of interference testing etc I understand that this point is moot, but I’m working through the backups if the WAAS box goes dead and you still have a nav source. 

 

[81X]

10 hours ago, bradp said:

Another question. Apparently a GPS signal is required to perform VOR/ localizer / ILS approaches or to track a Nav course   

If the signal from the primary navigator is disrupted is the signal from the G5 sufficient to provide that aiding?  In the case of interference testing etc I understand that this point is moot, but I’m working through the backups if the WAAS box goes dead and you still have a nav source. 

 

I’m not sure, great question. Maybe I’ll try that tomorrow- pull the GPS CB on an ILS before and during.  It’s slways best to learn these things in VMC!  

[Bob - S50]

3 minutes ago, 81X said:

I’m not sure, great question. Maybe I’ll try that tomorrow- pull the GPS CB on an ILS before and during.  It’s slways best to learn these things in VMC!  

Ya, but if you do that won't you lose the ILS signal from the GTN too so there won't be anything for the AP to fly?