The so-called Black Box on commercial planes, the flight data recorder is painted this color
So black doesn't necessarily connotate color but actually conveys the .... What 
commercial flight route requires the most (minimum possible)... [DOC] [TLE] Flight recorder - Wikipedia [PAR] A flight recorder, commonly known as a black box, although it is now orange-
coloured, is an electronic recording device placed in an aircraft for the purpose of 
facilitating the investigation of aviation accidents and incidents.