Vertical card compass compensation

[rjcthree]

Is it possible that the 8 degree or so panel angle makes it more difficult to swing a VCC? In my case it's a PAI-700 in the panel, away from big power, no difference engine running, non running, a smidge (a twitch, 2 deg?) when transmitting. I can compensate N-S, but E-W I'm way out - 15 degrees or so. It's a tip up, so no steel. Brass screws.

Full disclosure, I might have over-adjusted the compensation elements at some point - could I have permanently damaged it?

Thanks, Rick

[plehrke]

Originally Posted by rjcthree

I can compensate N-S, but E-W I'm way out - 15 degrees or so.

My original swing of the compass had my N/S off by 10-12 degrees and only a few degrees off E/W. A year after started flying, I tried again and did not inprove but made it a little more even. I was able to get N/S down to 5-7 degree error at the expense 4-5 degree of E/W error. I determined good enough and have never looked at the compass again in 10 years of flying.

[Tbone]

The way we swing our compasses (we'll over 50 aircraft a year) is to point north and adjust to 0. Swing west and adjust to 270. Swing to south and adjust to 1/2 the deviation. Hopefully not over 4 degrees. Swing to 90 and adjust 1/2 deviation. Again not over 4 degrees. Recheck north. Should be within 4 degrees. If out restart. Don't split difference. RESTART. We validate against AHRS and can't be out over 4 degrees. We use a certified calibrated master compass and have aircraft powered up in flight configuration. We are calibrating a SIRS compass and not familiar with VCC but principle should be same. If compass won't calibrate I would look towards faulty compass. Remember flight configuration....

[stneki]

Helped install the same one in a Warrior. We could never get it callibrated. It turned out we over adjusted it and it had to go back for repairs.