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 I (contained in this document) is composed of 24 lessons requiring 115 hours of instruction. Topics covered include safety; aircraft familiarization; physics; electron theory; magnetism; DC generation and basic circuit symbols and terms; wiring diagram fundamentals; control and protective devices; multimeter; Kirchoff's current and voltage laws; Ohm's law; circuits; alternating current; capacitance; inductance; AC and DC motors and control circuits; solid state devices; magnetic amplifiers; and trainer aircraft air conditioning system. (KC)