{"id":"F2006B06403","name":"AD/PW-P/15 - Crankshaft Flyweight and Flyweight Liners - Inspection and Modification","slug":"ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47731,"registerId":"commonwealth-F2006B06403-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PW-P/15 - Crankshaft Flyweight and Flyweight Liners - Inspection and Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Pratt and Whitney Piston Engines\n\n \n\nAD/PW-P/15 Crankshaft Flyweight and Flyweight NK\n\nLiners - Inspection and Modification\n\n \n\nApplicability: R985 series.\n\n \n\nDocument: Pratt & Whitney SB 1758 Rev. A.\n\n \n\nCompliance: Installed Engines - Before installation in an aircraft following each overhaul. Spare engines - Before installation in an aircraft after 2 November 1967 unless previously inspected and reworked or replaced as necessary in accordance with Pratt & Whitney SB No. 1758 or P&W Wasp Junior Overhaul Manual P/N 123440 at last overhaul.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused on a specific mechanical component in a specific engine series. It has not expanded beyond its original purpose of ensuring crankshaft flyweight integrity in Pratt & Whitney R985 engines."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined applicability (R985 series engines)","Single reference to external technical document (Pratt & Whitney SB 1758 Rev. A)","Simple conditional logic: two compliance pathways (installed vs spare engines) with clear date threshold (2 November 1967)","No nested exceptions or cross-references to other legislation","Straightforward mechanical/technical requirement without legal contingencies"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Pratt & Whitney aircraft engines** (the R985 series, commonly known as \"Wasp Junior\" engines).\n\n**What it requires:**\n- Owners and operators must inspect and potentially modify the **crankshaft flyweights and their liners** — these are mechanical components inside the engine that help control engine speed and timing.\n- The work must follow specific instructions in **Pratt & Whitney Service Bulletin 1758 Revision A**.\n\n**When it must be done:**\n- For engines currently in use: **before the engine is installed in an aircraft after each overhaul** (a major service where the engine is completely disassembled and rebuilt).\n- For spare engines sitting in storage: **before installation in an aircraft if they haven't been checked since 2 November 1967**, unless they were already inspected and fixed according to the manufacturer's guidelines at their last overhaul.\n\n**Why it matters:**\nThis directive addresses a potential safety defect in these engines. If the flyweights or liners fail, the engine could malfunction in flight — with serious consequences. The rule ensures older engines (some potentially decades old) meet current safety standards before returning to service."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive, as presented, sets inspection and modification requirements for R985 series crankshaft flyweights and liners consistent with the referenced Pratt & Whitney service bulletin and overhaul manual. The text does not indicate any expansion or narrowing of the applicable engine population or compliance conditions relative to the stated requirements; it simply mandates compliance with SB 1758 Rev. A and specifies when inspections or rework must occur (installed engines: before installation following each overhaul; spare engines: before installation after 2 November 1967 unless already inspected/reworked/replaced in accordance with the referenced documents)."},"complexity_factors":["Narrow technical scope: applies only to Pratt & Whitney R985 series engines (Applicability).","Dependence on an external manufacturer document (Pratt & Whitney SB 1758 Rev. A) for the required procedure (Document).","Simple, time‑based compliance requirements (before installation after overhaul for installed engines; before installation after 2 Nov 1967 for spares).","Limited number of compliance paths: inspect and rework per SB or replace as necessary (spare engines clause).","Operational logistics risk (downtime, parts, labour) implicit in the compliance schedule rather than additional regulatory procedures."],"plain_english_summary":"This directive makes Pratt & Whitney SB 1758 Rev. A mandatory for R985 series engines: owners, operators and overhaul/maintenance shops must inspect and, if needed, modify or replace the crankshaft flyweight and flyweight liners per that service bulletin. Inspections are required before engines are installed after overhaul and before spare engines enter service (unless already done). It forces SB compliance, creating inspection/rework costs, downtime, or the option to replace parts/engines."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification","history":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification/history","analysis":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification/analysis","conflicts":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification/important-cases","documents":"/api/acts/ad-pw-p-15-crankshaft-flyweight-and-flyweight-liners-inspection-and-modification/documents"}}