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-8/55 Horizontal Stabiliser Skin Disbonding Follow-up 12/98 Applicability: All DHC-8, Series 100 and 300 aircraft which have horizontal stabilisers, serial numbers CAP 003 through CAP 214 fitted. Requirement: 1. For Horizontal Stabilisers, Serial Numbers CAP 003 through CAP 050: Perform an Ultrasonic Bond Inspection of the upper and lower skin panels (part number 85510025 and 85510026) for disbonding as outlined in de Havilland Non Destructive Testing Manual, PSM 1-8-7A, Part 5, Section 55-00-01. 2. For Horizontal Stabilisers, Serial Numbers CAP 003 through CAP 214: The inspection interval in the Airworthiness Limitations List (AWL) is reduced from 3 years to 2 years in accordance with Temporary Revision (TR) No. AWL 63 of the AWL in the Maintenance Program Manual PSM 1-8-7 (for Series 100 aircraft) and TR No. AWL 3-70 of the AWL in the Maintenance Program Manual PSM 1-83-7 (for Series 300 aircraft). These inspections are to be phased in as specified in Compliance paragraph 2. Disbonds beyond the local disbond limits defined in de Havilland document PSM 1- 8-7A, Part 5, Section 55-00-01 shall be repaired before further flight. Note: Transport Canada AD CF-98-24 refers. Compliance: 1 Unless already accomplished within the last 3 months, before 5 December 1998; repeat between 12 and 14 months after the initial inspection. 2. a. For Horizontal Stabilisers Serial Number CAP 003 through CAP 050: Following the Compliance 1 repeat inspection, inspect within the next 2 years and thereafter at intervals not to exceed 2 years. 2. b. For Horizontal Stabilisers Serial Numbers CAP 051 through CAP 214: 1. Where the next inspection falls due in 1998, unless already accomplished, perform the inspection as scheduled and repeat thereafter at intervals not to exceed 2 years. ii. Where the next inspection falls due in 1999, unless already accomplished, perform the inspection no later than 31 December 1998 and repeat thereafter at intervals not to exceed 2 years. iii. Where the next inspection falls due after 1 January 2001, perform the inspection 1 year earlier and repeat thereafter at intervals not to exceed 2 years. This Airworthiness Directive becomes effective on 5 November 1998. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Background: As a result of the inspection required by AD/DHC-8/51, a total of four aircraft with serial numbers close together were determined to have disbonds of the doublers and stringers on the upper and lower skin panels of the horizontal stabiliser. This discovery indicates that the bonding process was defective on a single batch of skins. The follow-up inspections of this Directive will ensure that no further problems exist in the above single batch or other batches of the bonded skin panels.