So we take my airplane up (fresh from the CAPS repack) and did a practice ILS and I was a bit all over the place on that approach, which was a bit unusual, but I chalked it up to just getting used to the 6 pack scan again. So we were getting vectors for another ILS approach and we were on the downwind when I was looking at my instruments and my attitude indicator is showing a 10 degree right bank, while every other instrument is indicating straight and level flight.
I ask my safety pilot, "does that look right?" He of course says no. So I take the hood off, and do some troubleshooting. Vacuum gage still in the green, DG still reading correctly, but no flag on the AI. Very odd. We tell the tower that we will continue this approach but it will be our last.
I didn't cover up the AI, and put the hood back on, and did my best to "ignore" the misreading AI, just to see how I would react. As we rolled through the various vectors to final, the AI reacted either slowly or wrongly. Straight and level awaiting the glide slope intercept it read a left turn this time.
It is incredibly difficult to ignore the main instrument in your scan. It was great actual partial panel practice, and a great reinforcer as to why you should cover up the wrong instrument. I keep post it notes in my flight bag for just such occasions and thankfully I have never had the reason to use it.
The vacuum system was inspected this past week and it checked out ok, so we are sending the AI out for repair, and I get to drive this weekend to my destination.
Fly safe!
