COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Pilatus Britten-Norman BN-2 Series Aeroplanes
AD/BN-2/62 Wing Spar Cap 3/98 DM
Applicability: All BN2, BN2A, BN2B and BN2T Islanders.
Requirement: 1. Inspect the top rear-spar cap, the web plates and the support brackets for cracks around the bolts, fasteners and rivets as described in the accomplishment instructions of Pilatus Britten Norman Service Bulletin BN2/SB.237. The inspection may be accomplished using either a flexible fiberscope or visually with the aid of a torch and mirror.
2. Repair aircraft that are found with vertical cracks of any length and/or horizontal cracks which are more than 6.35 mm (0.25 inch) in length.
Note: UK CAA AD 009-10-97 refers.
Compliance: 1. Unless already accomplished, inspect before 30 January 1998. Thereafter, inspect:
- aircraft found with horizontal cracks only, which are less than 6.35 mm (0.25 inch), at intervals not to exceed 50 landings, or;
b. aircraft last inspected visually using a torch and mirror, with no cracks detected, at intervals not to exceed 500 landings or 250 hours time in service, whichever occurs first, or;
c. aircraft last inspected using a flexible fiberscope, with no cracks detected, at intervals not to exceed 500 hours time in service.
2. Before further flight.
This airworthiness directive becomes effective on 7 January 1998.
Background: A number of aircraft have been found with cracks in the wing spar caps in the top main landing gear thrust block area, including aircraft on the Australian civil register. Left unchecked the cracks are likely to reduce the structural integrity of the wing below an acceptable level.