COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Propellers - Variable Pitch - Hartzell AD/PHZL/72 Counterweight Clamp Bolt Hole 12/98 Applicability: Hartzell Propeller Inc. HC-E4A-3(A,I,J) series propellers, with serial numbers HJ1 through HJ1040, that have been previously overhauled or have had a counterweight clamp bolt removed for any reason. Requirement: Unless previously accomplished: Perform a one time inspection of the propeller blade counterweight clamps for thread damage in the bolt holes in accordance the Accomplished Instructions of the Hartzell Propeller Inc. Alert Service Bulletin (ASB) No. HC-ASB-61-237, dated 17 July,1998. The replacement or re-assembly of propeller blade counterweight clamps is to be carried out in accordance with ASB No. HC-ASB-61-237, dated 17 July 1998. Compliance: 1. For propellers with 2,500 or more hours time in service (TIS) since last overhaul, inspect within 300 hours TIS, or 45 days after the effective date of this AD, whichever occurs first. 2. For all other propellers inspect within 600 hours TIS, or 90 days after the effective date of this AD, whichever occurs first. This Airworthiness Directive becomes effective on 5 November 1998. Background: There has been previous reports of thread damage caused by bolt hole failure and thread damage by cross threading, this damage has lead to counterweight separation in flight.