SAE AS 399B
This document has been declared Stabilized and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist.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.To specify minimum requirements for gyroscopically stabilized Magnetic Direction Instruments for use in aircraft, the operation of which may subject the instruments to the environmental conditions specified in Paragraph 3.3. This Aeronautical Standard covers minimum requirements for gyroscopically stabilized Magnetic Direction Instruments for use in aircraft.