COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pratt and Whitney Piston Engines AD/PW-P/18 Amdt 1 R1340 PMA Crankshaft 6/98 Applicability: Pratt and Whitney R1340 engines incorporating an Air Tractor, Inc. PMA crankshaft, P/No 90114. Note 1: This Directive is only applicable to engines that have had the crankshaft replaced with a PMA shaft, P/No 90114, during overhaul or repair since 12 September 1991. Requirement: 1. Inspect the crankshaft counterweights in accordance with Snow Engineering Service Letter No. 135. 2. Rework crankshaft counterweights in accordance with Snow Engineering Service Letter No. 134. Compliance with Requirement 2 is terminating action for the inspections introduced by Requirement 1 above. Note 2: FAA AD 96-15-02 also refers. Compliance: 1. Unless previously accomplished, initially no later than 300 hours time in service since new or within 10 hours time in service, whichever occurs last, and thereafter at intervals not exceeding 150 hours time in service since last inspection, or at each occasion a cylinder is removed, whichever occurs first. 2. At the next occasion the crankshaft is removed from the engine. This amendment becomes effective on 21 May 1998. Background: Cracks have been found in the crankshaft counterweights. In at least one instance a counterweight was liberated from the crankshaft resulting in an engine failure. This amendment provides additional information relative to engines affected by this Directive. The original issue of this airworthiness directive became effective on 10 October 1996.