No, Avionik Straubing can still do it and I will send it to them, they’re reportedly the only ones in Europe who can do these things these days.
I had bought it used from one of their customers, and apparently it was overlooked that this particular 27 year old SB had been done, since it’s one of the older serial numbers. They’ll replace the EPROM free of cost, a matter of couple days really, and I’m done.
The KFC 150 is an attitude based AP, actually pretty good, installed in the Malibus, many of the Bonanzas and Barons, and many more. The KFC 225 is the modern version of it; I am actually waiting for the Aerocruze, because I guess it will save me replacing the servos and wiring….
What is the fix – they send you a replacement EPROM?
HBK autopilot servicing is done pretty well only in the US nowadays. Last I heard, they pulled the plug on various authorised repairers – like this. This appears to be so for the KFC225 at least.
From the era, this sounds like an analog autopilot with a CPU which does just the user interface.
In aviation, that’s nothing :)
Still, these systems are in service today, and I have encountered two guys at least who had the same issue; it might help whoever has once wondered what’s going on.
I consider this behaviour as potentially dangerous, and I wonder why it has ever been certified that way. But that may be my personal opinion.
Only 27 years old then 
As If found out, there actually is an Allied Signal Service Bulletin, which at the time was customer option only, which resolves the issue by replacing an EPROM.
Can I upload it here somehow ?
It is not normal to do it so aggressively.
Yes that seems to be the case. It seems to be normal.
I consider it dangerous. Given the reciprocal situation – I descend through transition level, dial in from standard to local QNH, which is higher. KAS 297B thinks I‘m higher than I am, thus thinks it needs to increase descent rate, and goes into a nose dive. Nice….
Changing the altimeter setting made the autopilot suddenly see a lower altitude, it thus thought that the VS was too low and raised the nose to increase the VS back to the intended value?
yes, everything ok. I just had the KAS297B installed…..
