COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/25 Wing Leading Edge Flap System - Modification 1/81 Applicability: All models 747. Document: 1. FAA AD 80-19-05, Amdt. 39-3906; or 2. Boeing SB No. 747-27-2204. Compliance: As per requirement document No. 1. Background: Investigation has revealed that a single electrical fault in the leading edge flap circuits could cause an unscheduled deployment of the flaps.