COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 400 Series Aeroplanes AD/CESSNA 400/97 Amdt 1 Wing Front Spar Under Cap 1/95 Applicability: Models 421C S/N 421C0801 to 421C1807, and 425 S/N 425-0002 to 425-0236. Requirement: 1. Inspect in accordance with Cessna SB CQB 91-8 Rev.1 or MEB 91-7 Rev.1, as applicable. 2. Install SK421-142 or SK425-44 as applicable. 3. Install a repair scheme acceptable to the Authority that has been validated by the Cessna Aircraft Company. 4. Remove from service any repair scheme: 1. installed as a result of the initial issue of this Directive that is not in accordance with Paragraphs 2. or 3. above; and b. that does not have an inspection schedule incorporated into the aircraft's approved System of Maintenance that reflects the actual repair carried out, and the requirements of the following Compliance. Note: FAA AD 91-25-08 R1 refers. Compliance: 1. Unless already accomplished in the previous 300 hours time in service, inspect prior to 3000 hours total time in service or within the next 50 hours time in service after 08 December 1994, whichever is the later; thereafter if cracking is: 1. less than 50mm (2.00"), at intervals not exceeding 50 hours time in service until the applicable service kit is installed. Following installation of the the Service Kit inspect in accordance with the requirements of Paragraph 2; or b. not detected - reinspect at intervals not exceeding 300 hours time in service until applicable Service Kit is installed. Installation of the applicable Service Kit prior to any detectable cracking terminates the inspection requirements of this Directive. 2. If crack length is: 1. equal to or less than 50mm (2.00") - within the next 200 hours time in service, then re-inspect at intervals not exceeding 600 hours time in service; b. greater than 50mm (2.00") and less than 63.5mm (2.50") - within 50 hours time in service, then re-inspect at intervals not exceeding 600 hours time in service 3. Where any crack: 1. length is greater than 63.5mm - prior to further flight, and/or COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES b. is detected that is not parallel to the grain structure; i.e. inboard to outboard along the spar cap, irrespective of length - prior to further flight; then re-inspect in accordance with the intervals and procedures specified in the acceptable repair scheme. 4. Within 300 hours time in service since the last inspection. Background: Cracks have been found in the wing front spar upper cap adjacent to the landing gear actuator. If not rectified wing failure could occur. Amendment 1 includes acceptable repair schemes that will ameliorate the inspections or provide terminating action.