FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) Each required landing or hovering light must be approved.

(b) Each landing light must be installed so that --

(1) No objectionable glare is visible to the pilot;

(2) The pilot is not adversely affected by halation; and

(3) It provides enough light for night operation, including hovering and landing.

(c) At least one separate switch must be provided, as applicable --

(1) For each separately installed landing light; and

(2) For each group of landing lights installed at a common location.