This publication contains a teaching guide and student instructional materials for conducting a high school or adult vocational education course to train persons to perform duties as an aircraft environmental systems mechanic. Course content has been adapted from a military course. The instructional design for this course is self-paced and/or small group-paced. Instructor materials contained in the course guide include lesson plans detailing training equipment needed, training methods, multiple instructor requirements, and instructional guidance. The student material includes a workbook and programmed texts with review exercises. A bibliography and glossary of terms are provided to aid both teacher and students. The course includes information on organizational and field maintenance of aircraft pressurization, air conditioning, and air starter systems, and life raft inflation equipment. The course is composed of four parts (see note). Block III (contained in this document) is composed of 13 lessons covering 102 hours of instruction. Topics covered are the following: tools, hardware, safety devices, and wire repair; maintenance of moisture separators; maintenance of bleed air distribution ducting; air turbine motor maintenance; turbine refrigeration devices; advanced fighter/bomber air source control system, air conditioning system, and windshield clearing system; maintenance of air control units; anti-G suit system; canopy seal system; pressurization systems; and cabin pressure leakage check. (KC)