AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes AD/DHC-8/99 Fuselage Longitudinal Skin Joints 12/2004 DM Applicability: DHC-8 aircraft, Models 102, 103, 106, 201, 202, 301, 311, 314, and 315, with serial numbers 003 and subsequent. Requirement: A. Airworthiness Limitations Change Amend the Transport Canada approved maintenance schedule by incorporating the new and revised structural inspection tasks as introduced by Temporary Revision (TR) of Airworthiness Limitations List (AWL) of the DHC-8 Maintenance Program Manuals (MPM) specified below: DHC-8 Models MPM Task No. Temporary Revision 102, 103, 106 PSM 1-8-7 5310/29E TR AWL-92 TR AWL-93 5310/30A 201, 202 PSM 1-82-7 5310/29E TR AWL 2-31 5310/30A TR AWL 2-32 301, 311, 314, 315 PSM 1-83-7 5310/29E TR AWL 3-98, 5310/30A TR AWL 3-99 B. Phase-In Schedule The phase-in schedule for the structural inspection tasks detailed in Requirement A is as follows: 1. For aircraft that have accumulated less than or equal to 40,000 flight cycles at the effective date of this Directive: Perform the structural inspection task numbers 5310/29E and 5310/30A. 2. For aircraft that have accumulated more than 40,000 flight cycles, but not more than 57,500 flight cycles at the effective date of this Directive: 1. Perform the eddy current inspection as detailed in task numbers 5310/29E and 5310/30A. b. In addition, for aircraft models 106, 201, and 202, perform both the detailed visual and eddy current inspections at areas below floor, as detailed in task number 5310/30A. 3. For aircraft that have accumulated more than 57,500 flight cycles at the effective date of this Directive: 1. Perform the eddy current inspection as detailed in task numbers 5310/29E and 5310/30A. b. In addition, for aircraft models 106, 201, and 202, perform both the detailed visual and eddy current inspections at areas below floor, as detailed in task number 5310/30A. Note: Transport Canada AD CF-2004-16 refers. Compliance: A. Within 30 days after 6 October 2004. B.1. At the intervals specified in Requirement A. applicable Temporary Revision of Airworthiness Limitations List of the Maintenance Program Manuals. B.2.a. Within 5,000 flight hours after 6 October 2004 but not later than 60,000 flight cycles, whichever occurs first. B.2.b. Within 5,000 flight hours after 6 October 2004 but not later than 60,346 flight cycles, whichever occurs first. B.3.a. Within 12 months or 2,500 flight cycles after 6 October 2004, whichever occurs first. B.3.b. Within 12 months or 2,500 flight cycles after 6 October 2004, whichever occurs first. This Airworthiness Directive becomes effective on 6 October 2004. Background: The longitudinal skin joints in the fuselage pressure shell for DHC 8 aircraft have been identified as principal structural elements where visual inspection has been established as an inspection method. However, it was recently discovered that portions of the skin joints could not be properly inspected by visual means as these locations are hidden by other structures. Revisions have been made to the Airworthiness Limitations List of the DHC 8 Maintenance Program Manuals to implement newly developed eddy current inspection procedures, along with new and revised inspection requirements to ensure that the entire length of the fuselage longitudinal skin joints are properly inspected to prevent failure. David Villiers Delegate of the Civil Aviation Safety Authority 29 September 2004 The above AD is notified in the Commonwealth of Australia Gazette on 6 October 2004.