Compass Backlight: required or not?

[Flightcap]

Hey all,

I've been mulling over the magnetic compass backlight for a few days after messing up this question on an interview (I think).

Here's the setup: all aircraft dome lights work, both pilots have operable flashlights, passengers boarded, etc. etc. Captain goes to hit the starter and you see the magnetic compass backlight is burnt out. The rest of the compass works fine. Can you launch?

Refer to part 91.205, which states that required instruments and equipment must be in an operable condition. It also states that a magnetic direction indicator is required equipment. It does not, however, specifically state the backlight.

So, if I understand my own question, what I am concerned with is whether the backlight is considered part of the magnetic direction indicator if installed? Will failure of this component render the instrument legally unfit for flight?

Thanks in advance!