Originally Posted by Lonewolf_50
Vaguely, I should do a bit more homework to brush up on the basics. "Tumble" is the physical analogue (from old gyroscopes) I am trying to use to describe the function becoming unreliable, based perhaps on accelerometers going wrong, but I won't comment further as I think the l@ser ring gyro has been adapted due in part to its higher reliability. (Fault tolerance).
In theory (and I presume practice) if you rotate these essentially solid state no moving parts instruments fast enough or accelerate the rotation fast enough you may overrun some counter that is counting interference fringes. Then it becomes inaccurate. I would presume, probably safely, that this is outside the range of motions of even a military jet. The upset is quite different from tumbling a gyro with its reaction to forces perpendicular to its axis due to friction.
As to lost calibration, causes of that would, it seem, remain in the electrical, rather than physical motion, domain. Do I understand that correctly?
I would presume the most likely reason for lost calibration can be as simple as an electric power glitch that went beyond what its internal power supply can handle. As I mentioned above I don't think you can exceed its ability to count beat notes that come from the slightly different effective distances the light traveled clockwise and counter-clockwise (deiseal and widdershins if you will) around the "ring" of laser optics. Bang it hard enough and you might actually bend the optical bench destroying its accuracy and perhaps its ability to work. I'd expect that to require quite a bang, as with a serious attempt to break it with hammer or something like that.
Time will also cut its accuracy down. You measure rotation rate in steps. So if you remain rotating at not quite one full step from not rotating over time your heading will be different from what is reported by a significant margin. It works on the speed of light. So that would be a very small error that would require a very long time to add up to an accuracy loss.
Recovery after it's lost power or whatever requires a very accurate knowledge of the plane's exact geographic position (GPS), attitude, and heading relative to true North. That's easy on the ground, more or less. In the air it could be more than a slight bit difficult, especially when we get some vibration.
edit: auv-ee's description is excellent and in greater detail.
Do consider it.