This document applies to regulatory/approving authorities involved with decisions regarding the use of HIL directed into the navigable airspace. For the purpose of this document@ lights greater than 0.25 million candlepower meet the minimum threshold of an HIL. Lights not directed or reflected into the navigable airspace are not usually considered to interfere with aircraft operations. Laser systems are beyond the scope of this document. Purpose The purpose of this document is to provide guidance to regulatory/approving authorities on issues specific to the use of HIL directed or reflected into the navigable airspace.