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Exchange Autopilot options for a TB20

Peter wrote:

And very very few avionics shops have the capability to do this work, properly.

You clearly don’t know where to look. There are several shops in southern UK who are very capable of doing high quality GFC500 installations. They don’t advertise as they have plenty of work from recommendation.

Avionics geek.
Somewhere remote in Devon, UK.

You clearly don’t know where to look. There are several shops in southern UK who are very capable of doing high quality GFC500 installations. They don’t advertise as they have plenty of work from recommendation.

These firms must be really well hidden (you say they don’t advertise) so it is not surprising that I don’t know where to look

Anyway, it’s always worth nothing what someone doesn’t comment on (the bulk of what I posted) so it’s good to see that my cost estimates etc weren’t far off.

Administrator
Shoreham EGKA, United Kingdom

If you were a serious buyer then I’d put a quotation together with one of those companies that I work with, but you really aren’t going to change your KFC225 for a GFC500 so it’s not worth the effort. I do think your estimate is rather high but we’ll leave it for another day.

Last Edited by wigglyamp at 10 Apr 21:42
Avionics geek.
Somewhere remote in Devon, UK.

Your input is always appreciated, wigglyamp, however EuroGA is run for the community here, not for me personally.

My KFC225 works fine; I just need to fix the max roll angle which is currently about 16 degrees and should be 23.

Administrator
Shoreham EGKA, United Kingdom

T28 wrote:

This is a good video with a short demo of all AP modes in flight

I does seem a very capable autopilot.
Most shops can get better than the list price for the kits so maybe you can get it for a bit less but if you are talking a GI plus 2 axis plus the inevitable additional work once you open up the panel on a 20YO aircraft, it may be a bit less than 30k, but I dont see less than 25k for a well-done job.

Unfortunately a significant part of the autopilots I see in small aircraft have limited functionality due to improper installs.

If budget is no issue then my only concern is: will it still be working and somewhat supported 20-30 years from now like the legacy autopilots? At least those ar maintainable by someone with decent knowledge, tooling and a manual.

IAS mode is really interesting. I am not a fan because of the inevitable pitch excursions (like the ones you see i the video of almost 20 degrees) but it is nonetheless a much safer mode for climb than VSI or attitude. It reminds me of our past efforts to work with Boeing and Honeywell in tuning the speed gains on the 717 to minimize such pitch excursions but in the end the low gains required for passenger comfort were deemed unsafe since the resulting IAS excursions could be dangerous, especially at high altitude. VSI or attitude hold is more practical, but it needs a pilot looking…

Antonio
LESB, Spain

PIT mode (constant pitch) is perfectly ok for climbs all the way to the operating ceiling. Does the GFC500 have that?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

PIT mode (constant pitch) is perfectly ok for climbs all the way to the operating ceiling. Does the GFC500 have that?

Yes.

GFC500 has the following vertical modes:

PIT, IAS, VS, ALT, VNAV, GS/GP, TOGA

and the following horizontal modes:

ROL, HDG, TRK, NAV (which implies GNSS when the navigation source is a GPS navigator ), APCH, TOGA

ESKC (Uppsala/Sundbro), Sweden

Airborne_Again wrote:

GFC500 has the following vertical modes:

PIT, IAS, VS, ALT, VNAV, GS/GP, TOGA

My humble legacy 400B can only climb in attitude hold mode :( , but as Peter sais, it works perfectly fine, as long as the pilot is awake!

@Peter you surely need to adjust pitch down slightly as power wanes during climb, right?
Or even better: you have the perfect set up so you maintain pitch with decreasing IAS down to Vy as power wanes during climb??

Antonio
LESB, Spain

Generally sounds like that AP we’ve all wanted for decades :) or shall I say all of us who have ever had exposure to airliner style AP’s.

Antonio wrote:

IAS mode is really interesting. I am not a fan because of the inevitable pitch excursions (like the ones you see i the video of almost 20 degrees) but it is nonetheless a much safer mode for climb than VSI or attitude.

That’s the one I’ve been craving for years. VS is unsafe and in order to keep it somehow safe actually makes for flight profiles which are less than optimal. IAS climb (Boeing calls it level change) with constant power and IAS hold is what works really well, particularly in climb. For descent, with our piston engines, VS works better normally as Level Change /Open Descent/ IAS usually is flown in idle.

Peter wrote:

PIT mode (constant pitch) is perfectly ok for climbs all the way to the operating ceiling.

IAS in that regard is safer. PIT will hold a fixed pitch regardless of power behind it. IAS will hold the selected Airspeed and adjust pitch accordingly, therefore it will not ever fly the airplane into a stall.

LSZH(work) LSZF (GA base), Switzerland

Mooney_Driver wrote:

Generally sounds like that AP we’ve all wanted for decades :) or shall I say all of us who have ever had exposure to airliner style AP’s.

GFC500 also has envelope protection when hand flying. If the pitch and/or roll exceed configurable “reasonable” values, the A/P will apply force in the wings-level, zero pitch direction. Same thing for over/underspeed. Of course, you can disable this when you want to practise stalls, steep turns etc.

ESKC (Uppsala/Sundbro), Sweden
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