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KI256 problems, replacement options, etc

The pic shows the other two horizons which I have, which were both running straight.

After about half an hour, the KI256 straightened itself out.

Could it be dirt in the bearings, which later got dislodged?

The vacuum gauge was showing a good vac the whole time.

The ball was in the middle, and the fuel tanks were balanced to compensate for me flying solo, but the two other AIs not agreeing is a bit of a give-away.

Shoreham EGKA, United Kingdom

From here

I saw the KI300 at Aero 2016.

It looks very nice, and contains an internal battery which meets the certification requirement (for totally removing the vacuum system) but at about $7k is too expensive except for people who don’t want to re-do their panel. Most people in the piston GA market will go for an Aspen.

Shoreham EGKA, United Kingdom

my KFC200 autopilot has stopped working, the flight director on the KI 256 is not functioning.we are not sure if is a computer fault ( although it runs the the test function ok) or the KI 256 (which was o/h less than 100hrs)
Probably a long shot but can anyone help who has a spare KI 256 that I could borrow to hook up to check it out .

The KI256 has a simple FD interface which is easy to check with a DVM.

The only UK shop which IME had any competence on King APs was Lees Avionics / Gama. Try to make sure Harry Lees is around.

Shoreham EGKA, United Kingdom

Thanks Peter, where is the FD interface to be found?

KFC200 FD driver is inside the KC295 AP computer
even IF the FD part of the KI256 is unserviceble, the AP would be working.

I did not mention, the flight director works in roll but does not come up in pitch.

Rob – if you are doing this yourself you need a very good electronics engineer, with access to the maintenance manuals (those are not hard to find if you have contacts in low places).

The electronics involved is simply 1960s/70s stuff but to troubleshoot it one needs to actually understand electronics. This is why the vast majority of avionics shops can’t do this work – they are just wiremen, with a phone line to Garmin if the thing doesn’t work.

The KI256 acts as the pitch/roll source for most King autopilots. It contains what is basically an LVDT, bent into a circle, for pitch and another for roll. This is excited with supposedly 400Hz (actually more like 500Hz in some cases) from the AP computer.

The FD is an indicator only, with nothing going back to the AP computer.

Unless you find a friendly avionics shop you may find it difficult to borrow a KI256 because they are worth about $10k and if somebody has a known-working one, they will not be keen to lend it out because it will be a valuable spare part.

Shoreham EGKA, United Kingdom

Thanks all.

Just read that the KI300 doesn’t actually exist currently. Honeywell are talking Feb 2017 at the earliest. More vapourware from Honeywell, as usual…

Shoreham EGKA, United Kingdom
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