Having a strange problem with my AI. After 10 minutes of so of level flight the horizon bar drifts down (like indicating a climb). If I deliberately climb or descend or turn, the horizon bar comes back up to the proper height for a while, until it drifts down again with level flight. When the horizon bar is down, it still indicates banks correctly, just in the lower area of the dial.
The AI seems to erect normally when I start up, and has the normal slight "jitter" until it starts drifting down.
The suction seems OK, although a little low (4.8"). My A&P says the vacuum regulator is all the way tight. My DG seems to work correctly and doesn't precess noticeably for an hour of flight. Vacuum filter was changed during the last annual.
I'm guessing I need to have the AI overhauled. Has anyone else seen symptoms like this?
The AI seems to erect normally when I start up, and has the normal slight "jitter" until it starts drifting down.
The suction seems OK, although a little low (4.8"). My A&P says the vacuum regulator is all the way tight. My DG seems to work correctly and doesn't precess noticeably for an hour of flight. Vacuum filter was changed during the last annual.
I'm guessing I need to have the AI overhauled. Has anyone else seen symptoms like this?
