 MIL-HDBK-338B provides a more recent reference.In 1970, the U.S. Federal Aviation Administration (FAA) published a change to 14 CFR 25.1309 airworthiness regulations for transport category aircraft in the Federal Register at 35 FR 5665 (1970-04-08).This change adopted failure probability criteria for aircraft systems and equipment and led to widespread use of FTA in civil aviation.