Significance of "the clock"

[SaxMan]

I've read, as well as heard, repeated stories of when a plane gets written off, either due to an accident, war weariness, or combat damage, the first thing the crew (or the crew chief) tries to do is remove the 8-day clock from the airplane. What is the significance of removing the clock? Is it because it's a high quality timepiece, or is it more akin to removing the ship's bell? If it is more like a ship's bell, why the clock and not another instrument?

[b29flteng]

It's a high quality time piece.

[shrike]

Because the clock will work on your desk or workbench, where a gyro won't.

A government contract eight day mechanical clock a high quality timepiece.

[John Dupre]

I read that when Erich Hartmann forced landed one time he was busy removing the clock when he was fired on by Soviet soldiers and subsequently (briefly) captured. At that time the clock was in particularly short supply and pilots were expected to remove it and bring it back from the crash site.

[PropsRule]

I imagine the clock would be a useful tool for navigating, too. It would be easy to lose track of time while in an escape and evade situation. With a clock handy, the escaping pilot could concentrate on not getting caught, and then refer to the clock to do distance/speed/time calculations to determine his location.

I'm not sure how this theory would hold up after somebody points out that the pilots often wore wristwatches...

[TROJANII]

Probably when going across terrain, his speed would not be constant.