{"id":"F2006B06406","name":"AD/PW-P/18 Amdt 1 - R1340 PMA Crankshaft","slug":"ad-pw-p-18-amdt-1-r1340-pma-crankshaft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47741,"registerId":"commonwealth-F2006B06406-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PW-P/18 Amdt 1 - R1340 PMA Crankshaft","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPratt and Whitney Piston Engines\n\nAD/PW-P/18\n\nAmdt 1\n\n  \nR1340 PMA Crankshaft 6/98\n\nApplicability: Pratt and Whitney R1340 engines incorporating an Air Tractor, Inc. PMA crankshaft, P/No 90114.\n\nNote 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\n\n12 September 1991.\n\nRequirement: 1. Inspect the crankshaft counterweights in accordance with Snow Engineering Service Letter No. 135.\n\n2. Rework crankshaft counterweights in accordance with Snow Engineering Service Letter No. 134.\n\nCompliance with Requirement 2 is terminating action for the inspections introduced by Requirement 1 above.\n\nNote 2: FAA AD 96-15-02 also refers.\n\nCompliance: 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.\n\n2. At the next occasion the crankshaft is removed from the engine. This amendment becomes effective on 21 May 1998.\n\nBackground: 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.\n\nThis amendment provides additional information relative to engines affected by this Directive.\n\nThe original issue of this airworthiness directive became effective on 10 October 1996.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is an amendment to an existing Airworthiness Directive (AD). The amendment does not expand the scope beyond the original safety purpose; it merely provides 'additional information relative to engines affected' — clarifying which specific engines with the Air Tractor PMA crankshaft are subject to the directive. The core safety mandate (inspect and rework counterweights) remains unchanged from the original October 1996 issue."},"complexity_factors":["Single, clearly defined applicability criterion (specific engine model with specific replacement part)","Two straightforward requirements with clear sequential relationship (inspection then rework)","Compliance timing uses standard aviation terminology ('time in service') but with multiple conditional triggers (whichever occurs first/last)","Cross-reference to one FAA (US Federal Aviation Administration) directive and two technical service letters","No defined terms section — all terminology is industry-standard aviation maintenance language","Short document (approximately 250 words) with clear structure"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and repair of crankshaft counterweights on Pratt & Whitney R1340 engines fitted with Air Tractor replacement crankshaft P/N 90114, after cracks and at least one in-flight failure were found.  \n\nIt affects owners, operators and maintenance organisations; inspections must be carried out per the manufacturer’s service guidance at specified intervals, and counterweights must be permanently reworked when the crankshaft is next removed to eliminate the need for repetitive checks."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment supplies additional information and clarifications about affected engines and the inspection/rework requirements and timing, but does not broaden applicability beyond Pratt & Whitney R1340 engines fitted with Air Tractor PMA crankshaft P/No 90114 installed during overhaul or repair since 12 September 1991. The original AD first took effect on 10 October 1996; this amendment adds detail effective 21 May 1998."},"complexity_factors":["Technical specificity: inspections and rework target crankshaft counterweights, requiring specialist maintenance and parts knowledge.","Multiple compliance timings: initial deadline (300 hrs TIS or 10 hrs, whichever is later), recurring 150‑hour intervals, and inspection-on-cylinder-removal create scheduling complexity.","Terminating action: completing the prescribed rework (Service Letter No.134) at crankshaft removal halts further inspections, introducing a trade‑off between recurring inspections and a one‑off overhaul.","Narrow applicability: applies only to engines with Air Tractor PMA crankshaft P/No 90114 installed during overhaul/repair since 12 Sept 1991, requiring accurate maintenance records.","Dependence on external documents: mandates compliance with Snow Engineering Service Letters No.135 and No.134 (external technical instructions).","Safety urgency: based on discovered cracks and at least one counterweight liberation and engine failure, increasing practical enforcement priority.","Cross‑regulatory reference: notes FAA AD 96‑15‑02, implying coordination with foreign airworthiness guidance."],"plain_english_summary":"This directive requires owners/operators of Pratt & Whitney R1340 engines with PMA crankshaft P/No 90114 to inspect crankshaft counterweights per Snow Engineering Service Letter No.135 and to rework them per Service Letter No.134. Inspections must start within 300 hours TIS or within 10 hours (whichever is later), recur every 150 hours or when a cylinder is removed, and the rework at next crankshaft removal ends the inspection requirement. It applies to PMA shafts fitted during overhaul/repair since 12 September 1991 and shifts compliance costs to owners/operators and maintenance providers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft","history":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft/history","analysis":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft/analysis","conflicts":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft/conflicts","importantCases":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft/important-cases","documents":"/api/acts/ad-pw-p-18-amdt-1-r1340-pma-crankshaft/documents"}}