It looks like this one has not been serviced since the Great War. Powered by a rather common Swiss pocket watch movement at least some parts are obtainable. A dry broken main spring and many other issues......

The hairspring must be adjusted.

Looks good enough....

Double checking the strength of the replacement mainspring.

everything into the cleaning machine......

wind up the new (old) spring for insertion in the barrel.

Assemble the balance and adjust the beat......

Everything has been ticking away for a while. Nothing slipping or otherwise in error.....

At the factory, the dial was attached to the case by three double strikes, staking it in place. This is how I could tell that it had not been taken apart since it was first built. Because the movement could not be removed without taking off the dial. So, now it is reattached by re-staking it as close as possible to the original stake marks.

Now it's back to life ticking happily and keeping time. Ready to re-install in a Spad perhaps? Or more likely hanging out on my desk.

Good evening and happy collecting!

Great post Greg.
These old military clock/watches make fantastic desk clocks.
You have inspired me to dig out some of my aircraft time pieces.
Thanks for the post and inspiration.
Dave

Very nice job, Greg! It is great to see one of these brought back to life. My Favre-Bulle is a bit different in that I have a DOXA movement in mine. The couple of other Great War Favre-Bulle cockpit clocks that I have seen also had DOXA marked movements in theirs. I am not seeing a maker's marking on yours, is there one? Is it possible that yours has a regular pocket watch replacement movement or perhaps Favre-Bulle used different manufacturer movements? I don't know but I would appreciate hearing your thoughts on these.
Here are some photos of mine - sorry for the small size of these images but the 220 size restriction on photos makes it difficult to post more detailed photos:

here is the back with the back cover removed. It is a metal disk that exactly fits into a recess around the edge and snaps into place. It is popped out using a tiny screwdriver inserted in the little cutout on the edge.

Here is the movement in mine - a closer view of the back with the back plate off:

And zooming in some more:

And still closer on the upper half of the movement:

And the lower half of the movement:

Hi Jim.

Sorry for the confusion, I did not bother to post images of the front and back of the completed movement. It is in fact a Doxa movement and marked as such, the same as your clock and the same as my other Bulle aircraft clock. I have worked on a few of these and it looks like Doxa was the only movement Bulle was using.

Thanks, Greg. You have done a great job bringing back that one from being a literal 'basket case'.