The disclosure addresses an external lighting unit for an aircraft. This external lighting unit includes a lighting unit housing have a mounting flange that is configured to provide a reduced contact with a supporting structure (e.g., a tail cone of an aircraft), which in turn reduces conductive heat transfer between the supporting structure and the lighting unit housing (more specifically reduces conductive heat transfer between the supporting structure and a printed circuit board that is disposed within the lighting unit housing and that may be seated on a portion of the lighting unit housing). Open spaces on the surface of the mounting flange that face toward the supporting structure may be occupied by a thermal insulator.