COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 3100 (Jetstream) Series Aeroplanes AD/JETSTREAM/79 Main Landing Gear Brake Unit 10/98 DM Applicability: Jetstream Series 3100 and 3200 aircraft as detailed in the requirement document. Requirement: Action in accordance with British Aerospace Regional Aircraft Alert Service Bulletin 32-A-JA980540. Note: UK CAA AD 003-07-98 refers. Compliance: Unless already accomplished, action in accordance with Part 1 and Part 2 of the Requirement document before 31 July 1998. This airworthiness directive becomes effective on 22 July 1998. Background: An incident has occurred where a brake unit heat pack was found to be totally worn when the indicator pins showed 0.1 inches of wear remaining. This directive requires a check of the wear remaining length indicated by the wear indicator pins and inspection to determine that the indicator pins are set correctly. There is a possibility that a fully worn heat pack in a brake unit may not be indicated as such by the indicator pins if not set correctly, which is a potentially unsafe condition.