COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
DHC-6 (Twin Otter) Series Aeroplanes
AD/DHC-6/71 Fuselage Station FS 239 Frame 11/95
Applicability: All DHC-6 aircraft.
Requirement: Inspect the fuselage frames for cracks by visual methods in accordance with the Accomplishment Instructions described in de Havilland Service Bulletin 6/521.
Note: Transport Canada AD CF-95-12 refers.
Compliance: Within 1200 hours time in service after 12 October 1995 or before 12 October 1996, whichever occurs first.
(a) If crack(s) are found which are within the tolerances specified in paragraph 5, Accomplishment Instructions of SB 6/521, perform repetitive inspections in accordance with de Havilland Inspection Requirement Manual, PSM 1-6-7 Temporary Revision 77, or as detailed in PSM 1-6-7 normal revision No.8, when issued.
(b) If crack(s) are found which exceed the tolerances specified in paragraph 5, Accomplishment Instructions of SB 6/521, repair or replace the subject part area before further flight.
Background: There have been two reported instances of cracking on the skin flange of the machined fuselage frame at fuselage station FS 239.