(AC-43.13-1B/2A with Change 1) Change 1 incorporates extensive new material on Welding and Brazing, Inspection and Maintenance of Landing Gear, Aircraft Electrical Systems, Aircraft Avionics Systems, and an entire new section on Human Factors. This reference book also includes AC-43.13-2A, Acceptable Methods, Techniques and Practices - Aircraft Alterations. ISBN# 0-89100-306-1.