14 C.F.R. § 155.3
(a) Section 4 of the Act of October 1, 1949 (63 Stat. 700) authorizes the Administrator to grant the releases described in § 155.1, if he determines that—
(2) The release will not prevent accomplishing the purpose for which the property was made subject to the terms, conditions, reservations, or restrictions, and is necessary to protect or advance the interests of the United States in civil aviation.
In addition, section 4 of that Act authorizes the Administrator to grant the releases subject to terms and conditions that he considers necessary to protect or advance the interests of the United States in civil aviation.