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IFD540 and GFC500 underspeed protection fail

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Bweb99 View Drop Down
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    Posted: 12 Jul 2020 at 9:06pm
We just picked up our Piper Lance with a brand bee GFC500/ dual G5 installation. We are now told the the under-speed protection of ESP will not function since the IFD 540 does not provide the proper label for it to work. Is there any solution out there that my installer is unaware of or is this something that is being worked on like enabling VNAV? Garmin rep replied to my post on another Forum I posted on and said that IFD540 isn’t approved as a navigator per their STC. Is this an avionics shop problem I should be aware of? I can’t believe there aren’t a lot of other similar configurations to ours.  I just spent a lot of money on an autopilot that won’t do what I want it to.    Thanks in advance...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dmtidler Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jul 2020 at 10:29pm
Originally posted by Bweb99 Bweb99 wrote:

We just picked up our Piper Lance with a brand bee GFC500/ dual G5 installation. We are now told the the under-speed protection of ESP will not function since the IFD 540 does not provide the proper label for it to work. Is there any solution out there that my installer is unaware of or is this something that is being worked on like enabling VNAV? Garmin rep replied to my post on another Forum I posted on and said that IFD540 isn’t approved as a navigator per their STC. Is this an avionics shop problem I should be aware of? I can’t believe there aren’t a lot of other similar configurations to ours.  I just spent a lot of money on an autopilot that won’t do what I want it to.    Thanks in advance...

It is my understanding that the GFC500 ESP auto-level and underspeed protection features require a correct format AGL input from the GPS navigator. Correct me if I'm wrong; however, I believe only the GTN 650 and750 navigators currently ouput the proprietary format with AGL information usable to the GFC500. I'm under the impression that even the G* 430/530 series (which the IFD's were designed as a direct replacement for) do not have the AGL output to the GFC500 and also do not allow the ESP auto-level or underspeed protection. 


Edited by dmtidler - 12 Jul 2020 at 10:30pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dmtidler Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jul 2020 at 10:39pm
It is also my understanding that with the GFC500 autopilot engaged there is still a low speed protection (MIN SPD) that will not let the autopilot fly the airplane below a set configured minimum airspeed. I believe this is completely independent of the ESP system and does not rely on an AGL input from the GPS navigator.

Edited by dmtidler - 12 Jul 2020 at 10:42pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote paulr Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 2020 at 8:11am
Originally posted by Bweb99 Bweb99 wrote:

Garmin rep replied to my post on another Forum I posted on and said that IFD540 isn’t approved as a navigator per their STC. Is this an avionics shop problem I should be aware of?

I would say that, yes, if the shop has installed something that is not permitted under the STC that it's a shop problem and not an Avidyne or Garmin problem. Do you actually have any recourse? That's a very different question. I poked around and found AC 20-188 (https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-188.pdf), which seems to say (on p4) that it's the installer's responsibility to double check the STC before proceeding. It sounds like they didn't do that.

What could the shop do to make this right?

(I saw the Garmin response you mention, and it just reinforced my determination not to do business with them.)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gring Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 2020 at 3:40pm
What is done is the installer shop obtains a field approval using approved data for installation of equipment not on STC list.  Since the IFD540/440 is a direct slide in replacement for the G530/430, it isn't s stretch for the installer to obtain approval.  THis is done every day all over the country for installation of equipment.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote paulr Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 2020 at 3:48pm
I believe I read that the GNS430/530 also doesn't emit the label required for underspeed protection on the GFC500. However, I don't have either a GNS or the GFC so I am not strongly motivated to go look that up.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dmtidler Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 2020 at 3:55pm
I'm curious if the Autopilot Underspeed Protection works in your Lance? Are there any other issues between the devices? 

I've read that the ESP Low-Airspeed (and ESP Auto-LVL) will not work without a GTN navigator or G3X PFD with a valid terrain database connected to the G5's. I did some additional research into this because I'm considering a similar setup in my Archer. I referenced the latest G5 PG, PA-28 GFC 500 Flight Manual Supplement, as well as a couple of GFC 500 training videos (one was produced by Garmin and the other appeared to be produced by Garmin and Sporty's). 

All I can say is that there is little to no consistency in operating manual terms and the video solely produced by Garmin seemed to conflate the ESP triggered Low-Airspeed Protection with the Autopilot Underspeed Protection (USP) as one and the same where none of the other references do that. In fact, according to the PA-28 GFC Flight Manual Supplement, Autopilot Underspeed / Overspeed protections are even set at different limit airspeeds than the ESP Low-Airspeed / High-Airspeed protections are. 

The contradictions in information all left me questioning what advertised protections are really going to be available with a dual G5, GFC 500, IFD540 setup.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bweb99 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 2020 at 7:40pm
I’ll go fly tomorrow and see what actually works and doesn’t.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dmtidler Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jul 2020 at 11:19am
Did you get that flight in?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bweb99 Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jul 2020 at 11:31am
I did and min speed warning (in any configuration) does display on the G5 but there is no automatic autopilot input with flaps up/down or gear up/down.  The shop i had do the install is now asking if I would consider installing the panel mount GPS as it is an approved GPS source and the IFD540 is not.  While that solves the issue of approving the aircraft to service it leaves me with the IFD 540 not driving the G5 and the autopilot.
I’m pushing the repair station to get the G5 and IFD540 field approved but that is going to take a DAR that can do field approvals or a DER  to approve the data via 8110.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote chflyer Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jul 2020 at 12:49pm
Originally posted by Bweb99 Bweb99 wrote:

I did and min speed warning (in any configuration) does display on the G5 but there is no automatic autopilot input with flaps up/down or gear up/down.  The shop i had do the install is now asking if I would consider installing the panel mount GPS as it is an approved GPS source and the IFD540 is not.  While that solves the issue of approving the aircraft to service it leaves me with the IFD 540 not driving the G5 and the autopilot.
I’m pushing the repair station to get the G5 and IFD540 field approved but that is going to take a DAR that can do field approvals or a DER  to approve the data via 8110.

I don't agree with your shop's position. I have a G5/IFD540 combination installed for over a year on the G5 STC and it works fine. GNS units are approved as GPS position and the IFD are approved as GNS replacements.
Vince
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Post Options Post Options   Thanks (0) Thanks(0)   Quote compasst Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jul 2020 at 12:55pm
Suggest talking with TJ about your issues. Settings of Avidyne and settings of G5s are critical. Garmin won't help you as they only talk to dealers. Your installation is legal whether Garmin likes it or not.

The IFD install is approved by Avidyne, as is the G5 interface to it. The G5 interface to the GGC 500 is approved by Garmin. No extra GPS nor a Field Approval is necessary.  I have had dual G5s since they came out for use in non-experimental aircraft and they work perfectly with my IFD 540 that was installed as soon as they were approved. I have a GFC 500 installed for a month in my C177b Cardinal. All work perfectly. 

After seeing this thread, I flew this morning to test the safety features of the GFC. All worked perfectly. With GFC and its flight director not selected, the GFC took over at low speed set point and at bank and pitch set points just long enough to get aircraft safely away  from setpoints. It was subtle, but effective and only as long as needed to get back to safe conditions. The Level button also worked perfectly. You need some experienced support tech to look over the settings.

Private message me if you want help.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ddgates Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jul 2020 at 1:42pm
There are many aircraft flying around legally with their IFDs as navigation source with G* equipment also in the panel.  G* is never going to call out any alternative navigators.  Why should they - they want you to use their navigators, which carry a large profit margin.

It just means that when a new box comes out, Avidyne has to do the work to include the interface in their install manual, as we are now asking them to do for the GI275.

By comparison, Aspen does not call out one navigator but not another.  Neither does STEC.  Nor Dynon. Nor any other manufacturer I can think of.




Edited by ddgates - 19 Jul 2020 at 1:43pm
David Gates
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Post Options Post Options   Thanks (0) Thanks(0)   Quote compasst Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jul 2020 at 5:43pm
I just flew my Cardinal with dual G5s, GFC 500 and IFD 540 to test the underspeed protection function. I set up to climb at 500' VSI in normal climb mode, roll on and ALTS set for 3500'. About 3000' I reduced power by 5" and the airspeed dropped as one would expect. I dropped power another 5" to 15" MP. The airspeed continued to drop to about 74 kts. The 'Airspeed Airspeed' warning was sounding and the message was blinking on the AI G5. The autopilot did not let the airspeed go lower than 72 MPH (it was a bit bumpy) as the VSI began to go negative and the altitude began to drop. The VSI steadied about -500.

The entire time the GFC kept control of heading (the mode I had it set for) and kept the ALTS setting and the VSI mode engaged. I increased power at 2500' to maximum climb power and the VSI increased to maintain 500' VSI until the autopilot leveled off at 3500' as the ALTS switched to ALT and flight continued without ever getting into any dangerous attitude.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dmtidler Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jul 2020 at 5:53pm
That’s great to know...hoping to have a similar setup this fall. Hopefully the avionics shop will have TJ on speed dial if they have any settings issues or questions.
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