49 U.S.C. § 47153: Waiving and adding terms

the property no longer serves the purpose for which it was conveyed; or the waiver will not prevent carrying out the purpose for which the conveyance was made and is necessary to advance the civil aviation interests of the United States. The Secretary of Transportation shall waive a term under paragraph (1) of this subsection on terms the Secretary considers necessary to protect or advance the civil aviation interests of the United States. On request of the Secretary of Transportation or the Secretary of a military department, a department, agency, or instrumentality of the executive branch of the United States Government or a wholly owned Government corporation may waive a term required by section 47152 of this title or add another term if the appropriate Secretary decides it is necessary to protect or advance the interests of the United States in civil aviation or for national defense. the Secretary provides public notice not less than 30 days before the issuance of a waiver; and will not significantly impair the aeronautical purpose of an airport; will not result in the permanent closure of an airport (unless the Secretary determines that the waiver will directly facilitate the construction of a replacement airport); or is necessary to protect or advance the civil aviation interests of the United States.