Honeywell KFC225 autopilot roll servo failure

It might be a silly amount of paperwork, but then you'd more than likely have a reliable autopilot. As it stands, you are getting warranty replacements, but there is a time and hassle factor of getting them swapped out. Somewhere there is a break-even point.

Have you checked out the rest of the electrical system on the aircraft? Maybe there is some other problem that is burning this stuff out. This might even involve hooking up some kind of data logger and flying around for a while; some spikes might not show up in ground testing or on short flights.

Matt Roberds

I based my suggestion on a few different observations. I used to work at a flight simulator company and it was a lot easier to make the Collins radios work right than the King ones. At that job, and since then, I have also noticed that the "cheap" avionics package often involves King radios, while the "upgrade" packages involve Collins radios. Finally, I went on a job interview with Collins in 1996 and was totally impressed by the amount of shiny! stuff at the plant in Cedar Rapids. (Got an offer, too, but chose another offer in Dallas over Cedar Rapids. Probably should have picked Cedar Rapids.)

Matt Roberds

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Hmmm.... radios are one of the items where simulators invariably use a front panel mock-up with switches and pots signaling the host. They are not designed or provided by the avionics makers. Making a mock-up work doesn't have much relation to the avionics OEM, seems to me??

Brian W

It's a refurb; the weakness is in the process that is used on the way there.

A unit comes back with a "defective" tag on it. It is going to go to the person who originally designed it, and be checked out with lots of instrumentation? Of course not. It will go back into the factory test process, and if it passes the factory test then it is classed as working.

If there is an obvious fault that will get fixed, and statistically that will likely be the only fault, so that is OK. The problem is with faults that are intermittent, or faults that don't get picked up by the factory test. I've been in electronics design/mfg for 25+ years so know this problem well; in my business we scrap anything that comes back, just to make sure.

My warranty avionics bill totals something like US$100,000 and that is mostly Honeywell avionics, added up at list prices, over 2 years.

Hello Peter,

That would be a normal process.

If intermittent is flagged this should cause more diligence in the repair process. If the test folks can't duplicate the error there should be further investigation, at least in cases that involve a lot more than one unit. That's where the QC system should kick in with its database information. Or in the med biz, that is where the QC system has to come in on a mandatory basis.

I wonder how they survive. I ran a business for several years and warranty overhead was factored in on a "per product" basis. My boss would probably have fired me with cause if I had ever failed to see an epidemic trend in one of the lines we offered. It never happened but we watched that stuff like hawks.

On the part of the user I'd be mighty concerned about what happens after the warranty period ends. After that, every time the servo hangs you'd hear that slurping sound coming from your bank account.

Regards, Joerg

Joerg wrote

Absolutely right! But you are assuming that there is a process for feeding back the info from the original pilot. In this case, the unit works its way back through the Honeywell return chain. It's now been 3 years from my earliest roll servo failure, and there were plenty before me, on the KS270C servo. They just keep packing up....

I guess they survive because in a piece of avionics listing at $2000 the materials come to $100-$200. So the actual cost of supply of a replacement is just the latter figure. This ratio would be true for all avionics I've seen - right up to any IFR GPS.

Also all the failed stuff gets recycled. The bit that costs real money is the metalwork. The electronics cost peanuts, around $10 for a $2000 servo. I've seen what's in there - $10 max. The metalwork doesn't go wrong and gets re-used.

My warranty ended over 1 year ago. Honeywell offered me an indefinite extension on the KFC225, all the time it keeps packing up. I also purchased their extended warranty on all my other Honeywell kit - $4000 for two extra years. I got that back within 6 months when the KI229 RMI packed up (its 3rd failure) - that lists here in the UK at about US$7000.

Most serious owners go for litigation after that. The trouble is that litigation would not fix the electronics.

Hello Peter,

Quite scary. In medical, if there isn't a process for that the FDA or another agency shuts the place down.

I am not a pilot. My guess is that a roll servo failure usually doesn't lead to a crisis situation but I don't know. If that happens on gear that can cause grief the liability can be huge. $200 won't even pay for a single attorney hour.

They really need to have someone look into that. Whenever I do that for a client they usually break even on my fees within a month or so, just because of reduced field returns. Others shy away from hiring a consultant or other experts and try to hang on. Long term that won't work.

Just imagine if I would realize my dream of becoming a pilot. I'd probably rent because of the cost but what if I didn't and needed an autopilot? After reading your story here would I buy a Honeywell autopilot? Probably not. That's the hidden cost of sub-par designs.

Regards, Joerg

Not always. Many of the radios I worked with (business jet and up) were the kind where there was just a control head in the panel and the actual guts (tuner, etc) were someplace else. We used the real control heads and just dispensed with the remote guts. For the Collins radios, you could read the spec, set up the control and data lines to the control head, and get it right fairly quickly. For the King radios, reading the spec was only the first step of a long journey into undocumented goofiness. This pattern repeated itself with other hardware where we used the actual aircraft item complete, such as a FMS.

Matt Roberds

You may find that the manufacturer of whatever you buy has already made a similar decision :)