COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES PZL M18 Dromader Series Aeroplanes AD/PZL/4 Vertical Fin Rear Spar 13/95 Applicability: Model M18 aircraft with serial numbers up to and including 1Z013-25. Requirement: 1. Inspect the vertical fin rear spar part number D33.100.00.0 for buckling and cracks using a light and mirror. 2. If buckling and cracking of the spar are found, replace the spar with a serviceable part. Note: Transport Canada AD CF-95-09 refers. Compliance: 1. Within 100 hours time in service after 7 December 1995, and thereafter at intervals not to exceed 12 calendar months. 2. Before further flight. Background: There is a possibility of cracking and deformation of the vertical fin rear spar. If not detected, this condition could lead to structural failure of the fin and seriously affect the controllability of the aircraft.