No person may operate a transport category airplane or, after December 20, 1999, a nontransport category airplane type certificated after December 31, 1964, that is equipped with a flight instrument pitot heating system unless the airplane is also equipped with an operable pitot heat indication system that complies Sec. 25.1326 of this chapter in effect on April 12, 1978. [Doc. No. 28154, 60 FR 65932, Dec. 20, 1995]