Yes I see your point and I perhaps should have worded my point a bit better. I meant “If you could afford an autopilot upgrade”
But really my point was that this is only a sim plane we are discussing, and I would like a full functioning autopilot in this virtual plane. My mention of the real world owner of the Commanche was a bit stupid and unneccesary.
I definitely liked having to learn to use the real world autopilot and appreciate the opportunity. As it is now winter here in the UK, I kinda like to fly RNAV IFR approaches but I am put off by the added workload of using the real world autopilot and find myself choosing another plane, when I really prefer to fly the Commanche.
CDI button. Cycle it. Even if it says it’s on GPS, it might not be on initial load.
One thing to remember is installing a new AP in an old plane involves a lot more than just finding a place on the control panel for the shiney new device and getting someone to certify it.
The new device has to integrate with existing avionics and the various servos and electric motors that move the controls may be incompatible or in some cases not even exist and the electrical system may not necessarily have the capacity to drive the new hardware either.
It can get very expensive.
I hear you. I actually like the autopilot on this but I’m also accustomed to a S-TEC 60 IRL which is very similar.
It would be nice IMHO to have a couple choices other than which Nav unit. I would enjoy a a GFC 500 along with the existing radios. Wouldn’t be an unusual setup although the installer would definitely need new servos IRL.
Fortunately in the sim Commanche, it’s just code. noughts and ones 
Yes, just 0s and 1s but getting them to do what you want, not a trivial adventure especially if the other groupings of 0s and 1s are simulating old technology….
Tuning a different AP probably involves tweaking the relevant PID’s in ai.cfg.
Anyone have the governor fail on them? I was a cruise, 12,000ft, everything in the green.
I’m outside taking some footage, when suddenly the prop RPM goes through the roof. I go inside and it’s over 3200rpm, and CHT spiking over 400!
I pulled throttle, and prop back, and landed in a field somewhere when the engine died on me. Good landing too. 
I checked out the engine but it showed everything in the green. I stared the engine, ran it to full power, and it looked okay, so I took off again. This time it died in flight, and the crankshaft broke.
Again, landed safely, replaced the crankshaft, and it happened again. At that point I overhauled the entire engine, with I think nearly 70 hours on it, and I’m now continuing my flight.
Could it have been oil perhaps?
Just wait for the preliminary NTSB report.
I’m not an expert by any stretch but I would say that it’s very possible that a big drop in oil pressure could cause a spike in RPM especially when the engine is under pressure or the AC is at something like cruise speed or above.
Not too sure tbh what could cause a drop in oil pressure but, yes, maybe insufficient/bad oil or even incorrect oil for the climate ??? Another reason in a real AC might even be worn engine bearings too perhaps ???
If you’re trying to intercept it from an angle greater than 10 degrees, yes, it’s not going to capture it. If it can’t turn more than 10 or 20 degrees, it can’t capture at more than 10 or 20 degrees.
Much better to set up on the flight path, then turn the S-tec on.
I was at a high enough altitude that I had the throttle fully forward, and only had about ~18” MP. If a piece of equipment had failed it would be nice to see what that was. Oil level was fine, and nothing was overheating. It wasn’t a gentle failure either, the engine was screaming in a few seconds.
Yes, it would be nice to know.
Thinking about it more it shouldn’t really be the engine. I think you said you had 70 hours on it so for maintenance purposes that doesn’t seem a lot and from what I recall it’s far short of it needing an engine overhaul.
Mmm … very interesting. If I was you I would post the question to the A2A devs and if you get an answer and have the time it would be good if you could let us know here too 
Given that the prop went absolutely berserk, and I was only able to get that below the redline by pulling it all the way back, I assume the governor had died, but that doesn’t show as a repairable part.
Good shout on the A2A forums. I have an account there, so will post something later on. I’d love to hear what they think of this.
There were some errors appearing on the engine management computer as well. I wish I had shot some video of it really. I think it said “O.P. 1” or similar.
Just as an aside don’t you think it’s great though when something like this happens and you can’t work out why it happened? It gets you thinking what you did wrong and helps you learn a bit more?
Personally, I love this kind of thing
Be aware that most single engine CSU are set to " fail forward " and hence with low oil pressure will automatically move into the low pitch/high RPM setting.
I note you say the oil levels were fine, however is the “OP1” you mention above potentially an oil pressure warning ?
IF - it is modelled correctly in the Comanche
AND EITHER - your oil supply did run low
OR - the oil pressure to the CSU failed or was blocked
THEN - the prop suddenly speeding up would be working as expected.
TLDR - O.P.1 is probably a low oil pressure warning in which case the CSU going into low pitch/ high RPM as a failsafe would be working as expected.
That’s possible, and makes sense. I checked after landing and oil was at maybe 65-70% so definitely not out of oil, but maybe dirty oil?
I wonder if I can force this failure again by manipulating simvars?
I’ve just been looking over the A2A manual, and even the EDM manual itself, and I can’t see any mention of that error code. I may have glossed over it, and will now search for “oil pressure” related texts.
EDIT: I just remembered something. There is a “state” folder where it keeps all your persistence stuff, where it also keeps backups. I could make a copy of the “live” one, and overwrite this with the last backup file, re-instating the plane to how it was when I flew it yesterday evening. That would let me check over things I missed, like the state of the oil, as well as perhaps record some footage of it dieing, assuming this wasn’t some random failure.
OK - so according to the A2A Engine Management Manual (linked below) the 0-P alarm state is indeed low oil pressure which would definitely result in a failsafe high rpm CSU.
Nothing wrong with the CSU it is doing what it is supposed to do when oil pressure gets too low.
**Alarm Priority **
If multiple alarms occur simultaneously, the higher priority alarm will temporarily “mask” the lower priority alarm(s). When an alarm occurs, note the cause of the alarm and tap the STEP button to clear the alarm indication so that you will be notified of any other alarm that might have occurred. The alarm priorities are as follows:
Highest priority
CHT High CHT
OIL High OIL temperature
TIT High TIT
OIL Low OIL temperature
CLD Excessive CHT cooling rate
DIF Excessive EGT span
VOLTS High battery voltage
VOLTS Low battery voltage
MAP Overboost Manifold pressure
O-P Oil pressure
LO REM Low fuel quantity remaining
LO H:M Low fuel endurance remaining
FF Low fuel flow
Lowest priority
see page 38 here:
This guy has your exact issue - oil pressure warning flashes up (he misses seeing it) followed by a low pitch/high rpm prop state.
