N204AK and I was at 8000 feet at 7PM enjoying a smooth cirrus evening on autopilot. During the preceeding hours, the nav needle had progressively increased its “crab” in a clockwise direction. Crosswind, lazy gyro, Garmin with a learning disability… all these things crossed my mind, but none of them took away from the beauty of the airplane.
In an instant, the plane banked sharply to the right and the nav flags popped up on the Century 1000 HSI. Rule #1 is fly the plane, and now I know that the aileron motors are indeed easy to overpower, just like my good buddy Matt Sullivan from Wings Aloft promised.
I pulled the fuses for the autopilot motors, and the need to fight the motors stopped. Now I could hand fly the plane without exerting significant wrist flexion/extension. It was trouble shooting time. I reset the fuses and the bank to the right came back immediately. I re-caged the gyro/HSI, but the bank returned. I unslaved and reslaved the gyro, but to no avail. I found that with the gyro unslaved, the autopilot didn’t bank adversely, and the Heading Bug DID act like an old fasioned wing leveler. And so I flew home with a wing leveler, autopilot motor fuses ON, and gyro unslaved. Glideslope #2 was used with Garmin #2 and the Garmin 430 Nav position 4 screen was used to simulate a gyro (and it does quite well. The lag is waaaay less that the compass).
I called Mike Busch at CD who jumped on the problem like a big dog. He set me up with Sterling Avionics in Concord, CA. I took the plane down after work where it was determined that the internal gyro within the Century 1000 had quit spinning. Cirrus sent him another one the next day and the problem is fixed.
Lesson: Remember the Nav-4 GPS compass screen.
: Electric gyros fail, too.
: For Century 1000 gyro failures, unslave the unit and fly the heading bug as a wing leverer. : The initial symptoms seemed to indicate possible failure in several systems. The Wings Aloft guide and course in invaluable.
And by the way, N204AK flew to Medford, Oregon yesterday, leaving a 400 foot ceiling at Concord and leveling off at 10,000 feet. TAS 150, 11 gph, and the flight came off without a hitch. This is a beautiful airplane.aa