Century 41 AP - Rolls hard right when activated

[vance.k]

Howdy Mooniacs;

Have a 79 231 with a Century 41, Aspen 1000 Pro PFD, and a Century AI.  AP was working properly for the two months that I've been flying the plane.  Flown probably 6-8 hours with it on and it worked flawlessly.  Had a shop working on adding a probe to my JPI along with some other maintenance (oil change, fuel pressure/flow, etc).  I noticed after that, the AP is no longer working properly.  Coincidence perhaps, but I think those are generally pretty rare.

Whenever it is activated, the plane rolls hard right.  I've tried it 3 or 4 times on different flights with the same symptoms.  I've let it go past 45 and it has no sign of stopping or slowing.  I had the same problem during the pre-buy, but the AI was not functioning properly then.  That turned out to be a bad vacuum pump.  Once replaced, the AP worked properly.  In this case, the AI appears to be tracking correctly.

I was thinking something might have gotten bumped or disconnected.  I had the shop take a quick look at it and they were unable to identify the issue.  They indicated the cables were still as expected.  Since it is rolling past 45, it seems it would have to be an issue between the AI and the AP, correct?  Doesn't seem the Aspen would be in play at all, if I understand correctly how this functions.

Any suggestions on where to look first?  Anything I can take a peek at myself?  I'm moving fields next week (KABQ to KAEG) and may start over with a new mechanic, just looking to get a jump start.

Thanks!
Vance

[toto]

For whatever it's worth (probably not much), I had an identical problem a few months ago with my C2k.  Turn A/P on, rolls hard until I hit the disconnect.  The symptoms did not seem to vary with heading bug or nav input, and I wasn't interested enough in being a test pilot to see whether/when it would stop rolling.  I attempted the on/off routine about 25 times and the behavior was absolutely consistent.

The avionics shop spent a day trying to find the problem, and came up with nothing.  They put the panel back together and said that they would need to send a technician up with me to help get to the bottom of it.

On my next flight, all symptoms had disappeared.  The shop said that their best guess was that removing and reseating all connections to the A/P fixed the problem.  YMMV..

[smccray]

I hadn't something similar with the KAP150- DMax re-seated the AI connection and it worked perfectly. 

[jetdriven]

The AI has a roll pickoff that limits bank to 30 degrees.  Start there and reseat the connectors. 

[vance.k]

Thanks all. I checked the connectors briefly this morning before my flight to Phoenix. Didn't have enough time to do too much, so reseated the one cable I could clearly get to. No joy. Will try to spend a bit more time on it when I return. 

Thanks again!

V--

[vance.k]

Bringing back an oldie, but wanted to follow-up and close the loop as I FINALLY got it fixed after 8 months of not having a functional AP.  I wasn't in a huge hurry, because I enjoy flying it and the ~180 hours or so of hand flying in that time period has probably been good for me.  But, I'm getting ready for my IFR checkride and wanted to have it functional and get some experience with it, in case I really need it some day.

After months of trying to get the local avionics shop at my field to troubleshoot it in earnest as well as trying to even get a return call/email from a shop at Centennial where I travel frequently, I finally threw in the towel.  I called Century directly on Tuesday and asked if I could just bring the plane to them and get it fixed.  They said come on down.  I went to Mineral Wells Wed evening and they pulled it into their hangar first thing Thurs while I hung out in their lounge with another gentleman who did the same thing.

They spent a few minutes troubleshooting, then pulled the AI and walked it across the street to the factory.  A couple hours later, it came back, rebuilt and with a clean bill of health.  One of their techs went up with me, calibrated it in the air, then gave me a tutorial on how to use all the functions, followed by programming up and letting the plane fly a full RNAV/LPV approach down to minimums (practice approach) and it worked flawlessly.  Left Mineral Wells and was back home in Abq on Thurs night.

In my 10 short months of airplane ownership, I seem to have had a pretty constant string of maintenance/repair experiences that were, let's say, 'meh'.  Mostly over-promise and under-deliver with a few that just flat out lie to get you off the phone with no intention of actually following through on their promises.  This experience, however, was as good as it gets!  Truly great people at Century (Matt, the service manager, especially) and the super friendly folks at the FBO, etc.  

Wish I had done it sooner and for anyone in a similar situation (unable to get qualified local help to fix it), I'd highly recommend this option. 

Cheers!
Vance

[DanM20C]

Thanks for the update.  I"m glad to hear good things about Century's support as I too have a C41.  Knock on wood, it has been working great.

I thought the Aspen could drive the C41?  Am I mistaken?  I'm hoping to eventually remove my AI and go vacuum-less. 

Do you have a single or double cue FD?

Cheers,

Dan

[vance.k]

Hey Dan,

Yes, they were definitely great to work with.  I'm unsure on whether the Aspen can fully drive the C41 for roll/pitch.  Mine definitely isn't connected that way and maybe wasn't considered.  I bought the plane with the Aspen already installed, so didn't do any of the research or design decisions on that install.  I don't believe my plane has a flight director.  

Vacuum-less is intriguing.  The AI is my only vacuum component at this point.

Cheers!
Vance

[DanM20C]

Vance,

I thought all C41s had a FD, C31s did not. I have a double cue and I believe Aspen only supports single. This might be an upgrade problem for me. I’ll cross that bridge when I come to it I guess.

What AI do you have?  Mine has a knob on the bottom left to turn the FD on and off. 

Cheers,

Dan

[vance.k]

Hey @DanM20C,

Not sure if all C41s had an FD.  Although, funny enough, when I was at Century, they had a large background banner system like you would see at a trade show back in the day.  It had photos of their older systems, including the C21, C31 and C41 setup.  I remember looking at that and thinking my AI doesn't look like the one with the C41 setup.  It looks like the C31 AI, but with the C41 control unit and badges.  

So no, my AI doesn't have the FD button or the command bars.  Perhaps it got swapped out somewhere along the way.  Maybe I'll dig through the logs at some point, but I don't recall seeing anything about that, at least not in the recent past.

Cheers!
Vance

[kpaul]

34 minutes ago, vance.k said:

Hey @DanM20C,

Not sure if all C41s had an FD.  Although, funny enough, when I was at Century, they had a large background banner system like you would see at a trade show back in the day.  It had photos of their older systems, including the C21, C31 and C41 setup.  I remember looking at that and thinking my AI doesn't look like the one with the C41 setup.  It looks like the C31 AI, but with the C41 control unit and badges.  

So no, my AI doesn't have the FD button or the command bars.  Perhaps it got swapped out somewhere along the way.  Maybe I'll dig through the logs at some point, but I don't recall seeing anything about that, at least not in the recent past.

Cheers!
Vance

I also have the C41, but no FD.

[Rotorhead]

@vance.k I know I'm bringing back an old post but appreciate the insight! I'm also an ABQ guy and have had some Century 41 issues; specifically with pitch pumps or not holding altitude. I'm planning on stopping at Mineral Wells on the way back from a trip next week. 

Good to see more Mooney men around here and look forward to seeing you in the air sometime!