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/78 Main Landing Gear Bay Auxiliary Spar 8/98 Applicability: All Jetstream Series 3200 aircraft. Requirement: Inspect in accordance with British Aerospace Regional Aircraft Mandatory Service Bulletin 57-A-JA 980441. Note: UK CAA AD 001-04-98 refers. Compliance: Unless the initial inspection is already accomplished; inspect in accordance with Part 1 of the Requirement document before 23 July 1998. Inspect in accordance with Part 2 of the Requirement document before 31 August 1998. This airworthiness directive becomes effective on 16 July 1998. Background: A main landing gear bay auxiliary spar lower boom has been found cracked in service. Cracking of the boom can cause a major reduction in airframe structural integrity.