MIL-T-5421B (AMENDMENT 2), MILITARY SPECIFICATION: TUBES, PITOT, ELECTRICALLY HEATED, AIRCRAFT (19 JUN 1985) [S/S BY MIL-DTL-5421D]., This amendaent forms a part of Military Specification MLLcT-5421B, dated 20 May 1969, and is approved for use by all Departments and Agencies of the Department of Defense.