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 12/8 Amdt 3 Main Rotor Blade Fork 10/86 TX Applicability: All aircraft fitted with Main Rotor Blade Fork. P/N 52110-3 Requirement: 1. Inspect all installed forks P/N 52110-3 to verify that each has a manufacturer's serial number permanently displayed on its outer surface. Remove from service forks found not to be serialized. 2. Visually inspect the P/N 52110-3 forks for cracks in the area of the outboard tension-torsion bar retention bolt hole. Washers and nuts need not be removed for this inspection. Note: This inspection may be accomplished by the pilot in command, in which case the precise AD reference shall be entered in a certification made on the maintenance release coincident with that for the daily inspection. 3. Remove the nut, washer and bolt and inspect the bolt hole bore and adjacent milled surfaces using a dye penetrant technique in accordance with ANO 108.10. Compliance: Requirement 1. Within 10 hours' time in service after 15 September 1986. Requirement 2. At each daily or overnight inspection. Requirement 3. Within 10 hours' time in service after 15 September 1986 or before achieving 250 hours component time in service, whichever is the later; and thereafter at intervals not exceeding 100 hours component time in service. Note: Inspections performed in accordance with the previous issues of this Directive satisfy the requirements of this issue. Background: This Directive implements the requirements of FAA AD 86-17-02 which supersedes FAA AD 79-18-04. Amendment 3 to the Directive extends the dye penetrant inspection to forks of all serial numbers following a fatal accident in the USA which involved failure of a shot peened fork.