@kenshirriff I could have used this years ago. I was in responsible for testing the standby flight instruments for the B-2, and the "turnball" (not sure anyone else calls it that) would work once, then fail when QA came to witness. I eventually found out why from the spec (which the USAF made hard to find), and rewrote that test.

As usual, a great view of interesting tech.

@kenshirriff @tubetime
Fascinating!
I never thought any electronics were involved with the orientation ball - I thought there's simply weight in the lower half, so whichever direction the plane is tilting, gravity would do the rest.