COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Hiller UH-12 Series Helicopters AD/HILLER 12/19 Main Rotor Blades - Inspection 11/71 Applicability: All models. Requirement: 1. Carry out a visual inspection for cracks in the main rotor blades P/No. 53100. Note: This inspection may be performed and certified by the pilot. 2. Inspect blades P/N 53100 for cracks using an approved dye penetrant method. Note: Any blades found defective shall be removed from service before further flight. Compliance: For Para. 1 - Before further flight. For Para. 2 - Within 10 hours' time in service after 16 Nov. 1971.