NORSEE or Non-Required Safety Enhancing Equipment is defined in FAA Policy No. PS-AIR-21.8-1602.

The policy addresses guidance and procedures for issuing design and production approval for equipment that not required by federal regulations but has the intent to measurably increase aircraft safety. The policy applies to CFR 14 part 23, 27, and 29 category aircraft. Amongst other information, the equipment should include installation instructions with detail that follow-on installations result in a consistent installation complying with manufacturer's instruction.