From
here:
Sec. 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.
[Doc. No. 27806, 61 FR 5171, Feb. 9, 1996]
Here is another source with some info as well. Questionable link but the info seems spot on.....
[edit on 28-3-2007 by Lost_Mind]