Why LRU's on aircraft are generally black in color?

Question

Why LRU's on aircraft are generally black in color?

Answer 1

Black is the best color for radiating excess heat (maybe?)

Answer 2

I should say to make your statement more exact is that LRU's in the avionics equipment list on aircraft are mostly black in color. Remember even pumps, fan blades, filters are  all "Line Replaceable Unit" or LRU's. Yet in fairness , CSD, IDG even FCU-APU are all painted black also.

To be honest it is a nice question and honestly I don't have the exact answer too.

When I was a component mechanic we just follow what the manual says in its use of paint.But mostly we just follow what the original color of the component before prior to depainting it. Only hydraulic LRU components are stricter because skydrol ruins the paint.

But avionics equipments or instruments esp. in the EE (electrical & electronics ) compartment are really all black, remember the Black box (orange) is usually located in the aft cargo compartment. perhaps avionic guys can explain it to us much better and truer. My guess is for uniformity and since avionics instruments some of which have BITE test equipment so the green lights or red lights are more visible in the EE compartment with an all black background. Remember the red light usually means a failure on the system or that particular equipment has failed.