COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes AD/DHC-8/58 Ladder Plate at Wing Station 139 13/98 Applicability: All DHC-8 aircraft, Models 101, 102, 103, 106, 201, 202, 301, 311, 314, and 315. Requirement: In order to detect cracks in the ladder plates before they reach a critical size and reduce the strength of the wing, accomplish the following: 1. Inspect in accordance with the Maintenance Program Manual (MPM) Temporary Revisions specified in the following table: Models Maintenance Program Manual Temporary Revision No. 101, 102, 103, 106 PSM 1-8-7 AWL-59 201, 202 PSM 1-82-7 AWL2-11 301, 311, 314, 315 PSM 1-83-7 AWL3-64 2. If cracks are found, before further flight, report to Bombardier Regional Aircraft Division, Downsview, Ontario for disposition. Note: Transport Canada AD CF-98-30 refers. Compliance: At the initial and repetitive flight cycles specified in the MPM Temporary Revisions. This Airworthiness Directive becomes effective on 3 December 1998. Background: A fatigue crack has been found in the ladder plate on the upper inboard side of the wing at wing station 139, stringer 6, on four aircraft. These cracks were found during the 40,000 flight cycle inspection when the wing access panels were removed. Temporary revisions have been made to the Maintenance Program Manuals in order to find these cracks before they reach a critical size.