Because one of these can fix it if it breaks, and in GA that is really essential. With CAN modules, it goes in the bin, one by one, until it starts to work again. Not even Merc dealers can troubleshoot/repair them.
Also a flap motor with a CAN interface would cost way more than the existing one, plus nobody will be able to troubleshoot/repair it. Intelligent peripherals in GA would create a huge money grab. Transport your new VW, CAN modules even for the headlights, to 20 years from now and try to get something fixed then… that will be hard enough but not many current cars will be running after 20 years, whereas with GA this is totally common. My “new” plane is now 16 years old…
This is digressing off the topic but intelligent modules in GA would be a disaster in the long run. I am sure glass avionics will be a disaster too but there will always be money to be made on replacements so these will be STCd, so there will always be the “€20k upgrade route”. What you won’t get is an STC to change a CANbus flap motor in a Mooney Model XYZ. AML STCd are rarely approved except for general purpose avionics boxes. You will be left to go around scrap dealers and installing whatever works off the books.
>>> Not even Merc dealers can troubleshoot/repair them.
Any reference for this?
You don’t need a reference; you own a Merc dealership so you can fly there and ask the chief… I am sure he will show you the test fixture(s) and repair facilities for every CAN module 
Aha, you make a claim and I am responsible for the reference?
Can i also do that? ;-)
Of course Peter is right that the higher the complexity, the lower the chances for an independent field repair. A Mercedes dealer replaces defective electronic modules and does not repair them obviously because it is neither economically viable nor is it possible as it’s a mix of hardware and software in a package. The swap part might cost 200 € for a car produced a million times and in the aircraft it will cost 5000 € with a lead time of 3 weeks and after 20 years no replacement will be possible.
However, the industry is going there even if Peter doesn’t like it. All aircraft delivered today have integrated avionics with functional units connected through a bus system (Ethernet in Garmin’s case). So it’s a fact that this shift has happened and customers enjoy the benefits of it (great integration, feature set) but are also the victim of the suppliers’ replacement policy and a possible end of life with no way out for these systems.
My answer was about the troubleshooting part of what Peter wrote. These CANbus systems are quite easy to diagnose. And, of course, “repairing” means changing defective modules. That’s how these repairs are done. But you also don’t “repair” a defective flap relay, or does anybody do that?
Independent field repair? How much independent field repair is there on current BK autopilots exactly? You still have to pull it out and send it somewhere, if not to BK itself.
@achimha is Garmin using a variant of AFDX?
Garmin G5 specific posts have been moved to the G5 thread
Interestingly there is a post by alioth there about CAN Bus being used for homebuilt autopilots, as I recalled.
With regard to the above debate, obviously repairing a flap relay is not the same as repairing a flap motor. The former is not done, not least because relays are cheap, especially if you locate the OEM part (and in EASA land it may be necessary to do it off the books because the maint org is likely to refuse a part without an EASA-1). The latter is highly desirable because a replacement can cost thousands, and often the fault is simple.
On the topic, I wonder how many airframes Garmin will STC. The obvious low hanging fruit is the SR22 population but they are sorted and anyway Avidyne have gone for them (being the most obvious low hanging fruit ). Next, is what? Mooneys, various Bonanzas? That alone is a good dozen “main” airframes.
@Shorrick_Mk2 as I understood it, Peter was not so much about an individual components and their complexity (and yes, there is a lot of field repairing of BK autopilots being done) but using highly abstracted interconnects that require intelligent components on the bus. This means instead of being a simple electric motor with wires coming from the autopilot, the servo would have a (CAN bus) controller inside and connect to an electronic bus to receive input commands. Definitely the modern and right way to do things but more difficult to troubleshoot and repair in the field than the current 1960s analog way of doing things.
Given where the industry is today (100% of all new aircraft equipped with G1000 and the like having exactly the design mentioned above), the discussion is kind of moot. It’s fantastic for Garmin, they own the complete avionics of the aircraft and they can charge whatever they like.
It’s not moot because, as I wrote above, this “complexity” is not an issue for avionics in terms of rendering a particular aircraft almost scrap – because avionics retrofits are usually possible, at “some price”, due to enough stuff being STCd.
So if Garmin went bust, the G1000 etc planes would not have to be scrapped. Avidyne etc would be delighted and for say 20k you could “fix it”. In the meantime, off the books G1000 repairs would flourish.
But if say a TB20 had an unusual flap motor made by some old boy in a shed in rural France (or more likely an untraceable French company without a website whose staff all left 20 years ago and whose stock Socata have been running down ever since) and Socata didn’t bother sorting out a replacement, the situation will be rather dire because there won’t be enough “meat” in it for someone to certify a new part. The TB fleet is about 2k and is being crashed or scrapped at a rate sufficient for sourcing these parts… for the time being. Now, this flap motor can be repaired, off the books if necessary, but a CAN version of it will just be scrapped. Especially as electronics has such a crappy record in GA, with nonexistent wx sealing in most things (including a G1000!).
The difference is huge.
This is rather digressing from the new autopilots however, largely due to the “I have nothing much to say so let’s windup Peter again” stuff which started in post #24…
