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KAP 140 AP Service

Hi,

We are having some trouble with our KAP 140 Autopilot in our C182S and the constant Check Pitch Trim error.

All the basic stuff was checked, no loose wires, electric trim is operational but no ALT hold.

Can someone recommend me a good avionics shop in UK that specializes in those type of repairs that you could trust, without charging a small fortune..

Thanks,

Philip

Evo400

Does this happen at self-test or in flight?

ESKC (Uppsala/Sundbro), Sweden

Does the shop have to be in the UK? Very very few avionics shops in Europe actually understand autopilots and have the equipment to do bench tests.

If there is no ALT hold, that has to be a big clue that something big is not right. The King autopilots use the altitude preselect to capture the altitude, and then use the pitch/roll output from the KI256 (or similar) vacuum AI, together with an internal accelerometer and an internal barometer, to maintain the pitch and altitude. What happens when you try to climb up to a preselected altitude?

Administrator
Shoreham EGKA, United Kingdom

Send eMail to Martin Scheifl, who is the A/P specialist of Avionik Straubing in Bavaria. He should know what’s wrong, and it might even be a good idea to fly there. [email protected]

The King autopilots use the altitude preselect to capture the altitude, and then use the pitch/roll output from the KI256 (or similar) vacuum AI, together with an internal accelerometer and an internal barometer, to maintain the pitch and altitude.

The KAP140 does not use any attitude information. For pitch it uses barometric pressure – and possibly an accelerometer. For roll it uses a turn coordinator.

ESKC (Uppsala/Sundbro), Sweden

@airborne again: it happens on pre flight test only and the warning light stays illuminated. We have flown in the last few hours with the circuit breaker off, due to this fault, as I believe the KAP 140 units are known for this type of pitch trim issues.
The problem we have is the aircraft is based in Ireland, the obvious nearest repair centre would be UK, but trying to find a good centre can be tricky.
For most repair centres the easiest option is guess work and elimation by replacing parts ( new servo here, new servo there, etc) and the costs are colossal by going that route. See it happening more often in the aviation trade…

Evo400

@airborne again: it happens on pre flight test only and the warning light stays illuminated. We have flown in the last few hours with the circuit breaker off, due to this fault, as I believe the KAP 140 units are known for this type of pitch trim issues.

We’ve had the exact same problem with our KAP 140 several times, but after a couple of restarts (pulling and pushing the circuit breaker) it has always passed the pre-flight test eventually and then worked correctly in the air.

Last Edited by Airborne_Again at 18 Jun 20:17
ESKC (Uppsala/Sundbro), Sweden

That’s exactly what I had. At last service mechanic cleaned connectors and since then I had it only once in three months.

LDZA LDVA, Croatia

At which seftest step does it Fails (number)
Most of the KAP 140 are caused by something outside the KC140.(AP computer)
To be sure you would have connect the AP system , to a (laptop) computer and look in to the error log (stored in the KC140)

KAP140 manuals

I have a big collection elsewhere…

Administrator
Shoreham EGKA, United Kingdom
16 Posts
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