COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Propellers - Variable Pitch - Hartzell AD/PHZL/37 Hard Alloy Blades - Inspection 7/74 Applicability: All blades identified with the letter "H" after the blade design number as follows: T10173H( )-( ), T10176H( )-( ), T10178H( )-( ) and T10282H ( )-( ), excluding the following Serial numbered propellers: HC-B3TN-2, S/N AG-275 and above. HC-B3TN-3, S/N BU-4624 and above. HC-B3TN-5, S/N BV-2210, BV-2213, BV-2214, BV-2216 and above. HC-B3TN-7, S/N CV-7 and above. HC-B3TF-7, S/N EX-3 and above. HC-B4TN-3, S/N EA-255 and above. HC-B4TN-5, S/N CD-62 and above. Document: Hartzell SB No. 105A. Compliance: For blades with less than 1000 hours time in service, within 100 hours time in service after 31 July 1974. Note: Blades with more than 1000 hours time in service are not affected by this Directive.