§ 91.209 Aircraft lights.

No person may: (a) During the period from sunset to sunrise (or, in Alaska, during the period a prominent unlighted object cannot be seen from a distance of 3 statute miles or the sun is more than 6 degrees below the horizon)— (1) Operate an aircraft unless it has lighted position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations area of an airport unless the aircraft— (i) Is clearly illuminated; (ii) Has lighted position lights; or (iii) is in an area that is marked by obstruction lights; (3) Anchor an aircraft unless the aircraft— (i) Has lighted anchor lights; or (ii) Is in an area where anchor lights are not required on vessels; or (b) Operate an aircraft that is equipped with an anticollision light system, unless it has lighted anticollision lights. However, the anticollision lights need not be lighted when the pilot-in-command determines that, because of operating conditions, it would be in the interest of safety to turn the lights off.