Text in force at CS27-10: from CS27-0, effective 14 Nov 2003.
The instrument lights must:
(a) Make each instrument, switch, and other devices for which they are provided easily readable; and
(b) Be installed so that:
(1) Their direct rays are shielded from the pilot’s eyes; and
(2) No objectionable reflections are visible to the pilot.
ED Decision 2003/015/RM · Source