SAE AS420B

This document has been declared NONCURRENT. It is recommended, therefore, that this document not be specified for new designs. NONCURRENT refers to those documents which have previously been widely referenced and may continue to be required on some existing designs.

This Aerospace Standard establishes essential minimum safe performance standards for Flight Director instruments primarily for use with reciprocating engine powered transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in Section 3.3. This Aerospace Standard covers Flight Directors for use on aircraft to indicate to the pilot, by visual means, the correct control application for the operation of an aircraft in accordance with a pre-selected flight plan.