Section 171.61 - Air navigation certificate: Revocation and termination(a) Except as provided in paragraph (b) of this section, each air navigation certificate of "Lawful Authority to Operate a True Light" is hereby revoked, and each application therefor is hereby terminated.(b) Paragraph (a) of this section does not apply to-(1) A certificate issued to a Federal-Aid Airport Program sponsor who was required to apply for that certificate under regulations then in effect, and who has not surrendered that certificate under § 151.86(e) of this chapter; or(2) An application made by a Federal-Aid Airport Program sponsor who was required to make that application under regulations then in effect, and who has not terminated that application under § 151.86(e) of this chapter.Amdt. 171-4, 33 FR 12545, Sept. 5, 1968 49 U.S.C. 1101-1120 ; sec. 307 , 72 Stat. 749, 49 U.S.C. 1348