The instrument lights must—
Provide sufficient illumination to make each instrument, switch and other device necessary for safe operation easily readable unless sufficient illumination is available from another source; and
Be installed so that—
Their direct rays are shielded from the pilot's eyes; and
No objectionable reflections are visible to the pilot.
Unless undimmed instrument lights are satisfactory under each expected flight condition, there must be a means to control the intensity of illumination.