I wonder if anybody here flies with it - apart from me.
It has a lot of reliability issues, almost entirely connected with the servos which have a habit of burning out and occassionally filling the cockpit with a nasty burning smell.
It had been going on for 10 years without any progress. Honeywell's lack of interest in fixing it is a genuine mystery, but very recent feedback from a contact there indicates there is some "political" dimension which prevents them from addressing it.
Over the years I had various ideas on the cause and communicated these to Honeywell, who showed an absolute lack of interest.
Very recently however I did some bench work with some burnt out servos which were donated by other pilots and together with having the full schematics (obtained via an "interesting" route) I narrowed it down to just a number of specific "design defect" issues.
I've updated a writeup I did a while ago here.
All airframes using this autopilot have been affected: C182, Caravan, various Beech models, various Piper models e.g. PA46, Socata TB-GT. In general these date from c. 1999 onwards but by c. 2003 all OEM customers designed-out the KFC225 due to the poor reliability. The TB models were perhaps the worst (and one becomes very unpopular raising this issue in the Socata owners' group due to the perceived impact on resale values) but the Caravan fleet suffered badly too.
Is it any surprise that a now obsolete autopilot is not getting support? It sounds like it is known to have problems and I doubt Honeywell really care about fixing it for a handful of GA aircraft.
Not suggesting this helps you much but it is probably the reality.
Is it any surprise that a now obsolete autopilot is not getting support?
I don't know how you would define "obsolete" but the only "obviously non obsolete" autopilots are, ahem, which? The GFC700 is the only one I can think of, but you need a G1000 to get it. The DFC90 is essentially vapourware, especially now that STEC have washed their hands of supporting any of their servos connected to it.
When it comes to product development, nearly all autopilots currently flying are "obsolete".
The KFC225 went into thousands of airframes.
I believe that Honeywell has restarted production of the KFC 225. I wonder if the new ones have the same part number for the servos ?
What is mean is autopilots going into new aircraft which are the only ones giving Honeywell income right now.
It seems like Garmin and Avidyne are the only "current" autopilots. There are a lot of DFC90s that have been/are being installed. I think you slightly overemphasise the STEC issue.
Peter, I am not defending Honeywell just saying that they are such a large company that they really don't care for an old product. Of course that is wrong
If they really are installing new KFC225s that could be different.
I believe that Honeywell has restarted production of the KFC 225. I wonder if the new ones have the same part number for the servos ?
Yes; a press release went out a while ago saying that (a copy is in my writeup). It was a dud, AFAICT.
They never stopped making the servos: KS270C pitch, KS271C roll, KS272C pitch trim (and I believe KS271C for a yaw damper). Looking at the serial numbers, they have shipped ~10k servos in 10 years i.e. a list price revenue of ~$30M. Significantly, these servos were made after new sales of the KC225 computer ceased. They have to keep making them because the ones that actually burn out are declared BER (beyond economic repair).
If they really are installing new KFC225s that could be different.
The unit found markets only as OEM - it was too pricey for retrofit installs. When the OEMs dropped it, that was it.
It's an excellent autopilot and the best for GA until the GFC700 came.
Peter, I am not defending Honeywell just saying that they are such a large company that they really don't care for an old product. Of course that is wrong
Sure... there is a "reason" why Honeywell are not fixing it. I can only speculate on what it is. My guess is that it could be any of these
)Based on 10 years of contacts with them and countless other owners, I am certain of all the above (except the last one) but have no idea on how they would rank them.
I think you slightly overemphasise the STEC issue.
Have you seen the statement from STEC (in my writeup, near the end)? That pulls a plug on the DFC90 (no legal way to service the servos) until Avidyne develop and certify their own servos. I've spoken to Avidyne a number of times over the past year or two about this. Talk and talk. They seem to be going for the market comprising of the few k Cirruses shipped pre-G1000.
If I was Avidyne now, I would be very unhappy, because they just have a few old cash cows - like the TAS605 I am spending £12k on next month 
The IFD540 is vapourware and has been for ages, but they are working really hard to get people to give them cash deposits. I only had to ask them some questions about the TAS product and they tried to get cash off me for an IFD540...
There is some litigation in the pipeline
I would seriously consider taking this path. You have done the work to establish that Honeywell's design is faulty and you have made every attempt to inform them.
Autopilots packing up in flight, burning components are a serious safety hazard. Honeywell are required to act. It is grossly negligent behavior and should somebody get harmed (think of the SR22 in Zurich where a failed alternator got the pilot to panic), they are in deep shit.
You have a list of affected owners. Find a competent attorney in the US and start a class action suit against Honeywell. There are enough contingency lawyers so it shouldn't cost much. Honeywell got deep pockets.
I know for a fact this has already been looked at. My guess (only a guess) is that a reason why this has apparently not yet been pursued is that it could cause the FAA to issue an AD on the autopilot, thus forcing all to be placarded INOP, etc. That would not be a desirable situation. I believe that a TSO holder is required to "sort out issues" (as a condition of the FAA approval) but I have no idea as to the required minimum process.
...You have a list of affected owners. Find a competent attorney in the US and start a class action suit against Honeywell. There are enough contingency lawyers so it shouldn't cost much...
Peter, I will join...
Amazing how the aviation industry works like this. Perhaps the rigorous and lengthy certification processes mean that manufacturers feel they have done everything they are responsible for upfront and can wash their hands of products like this.
All other industries have something called a factory recall where the manufacturer picks up the tab for having made faulty kit, and we have 'Airworthiness Directives' where the regulatory authorities invite those who've already paid thousands, tens of thousands or even millions for the kit to pick up the cost of rectifying an manufacturer's mistake.
The Lycoming crankshaft one was the most gobsmacking to me. An engine manufacturer produces duff crankshafts which could break in service, and their customers have to pay to have them replaced? Bizarre. Obviously we're talking US-based stuff here, but for a similar scenario in the UK would the Sale of Goods Act not apply? Terms such as 'fit for purpose' and 'merchantable quality' spring to mind.
