{"id":"F2006B05544","name":"AD/PA-24/45 - Engine Air Filter","slug":"ad-pa-24-45-engine-air-filter","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46473,"registerId":"commonwealth-F2006B05544-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-24/45 - Engine Air Filter","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPiper PA-24 (Comanche) Series Aeroplanes\n\nAD/PA-24/45 Engine Air Filter 9/99\n\nApplicability: PA-24-180 and PA-24-250 aircraft serial numbers 24-103 through 24-3687, and PA-24-260 aircraft serial numbers 24-3642, 24-4000 through 24-5028;\n\nfitted with a Facet engine air inlet filter part number (P/N) 638873 manufactured in the period January 1997 to September 1998.\n\nNote 1: Filters of concern can be identified by accessing the filter and locating the brand name and part number. Filters of concern are branded “FACET 638873” in 0.250”(1/4”) high white characters with no date code.\n\nRequirement: To prevent pieces of a damaged air filter from being ingested in the engine, inspect applicable air filters in accordance with Piper Service Bulletin Number (No.) 1022 and/or Purolator Service Bulletin No. 090298.01.\n\nNote 2: Civil Aviation Regulation (CAR) 42ZC (4) (d) permits the holder of a pilot licence, other than a student pilot, that is valid for the aircraft, to change the air filter. Therefore, should applicable air filters be removed from service prior to the effective date of this directive, the directive will no longer be applicable.\n\nNote 3: FAA Airworthiness Directive 99-05-09 refers.\n\nCompliance: Installed filters: At next inspection of the engine air inlet filter element or within 25 hours time in service from the effective date of this directive, whichever occurs first, and thereafter at intervals not to exceed 25 hours time in service.\n\nSpare filters: Prior to installation in a engine.\n\nThis Airworthiness Directive becomes effective on 9 September 1999.\n\nBackground: This directive has been issued to address reports of cracking and break up of certain air filter elements. The defects resulted from evidence of manufacturing errors in filters produced during the period January 1997 though September 1998. The directive requires applicable filters to be inspected for evidence of deterioration.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific manufacturing defect in a specific aircraft part. The scope remains tightly confined to the original safety issue — cracking Facet air filters on specific Piper Comanche models. There is no evidence of scope creep or expansion beyond the original safety purpose."},"complexity_factors":["Single, specific mechanical issue addressed (cracking air filters)","Limited applicability: only three aircraft variants with specific serial number ranges and one specific part number from a defined manufacturing period","Clear identification method provided (visual check for branding)","Simple compliance timeline: 25 hours time-in-service or next inspection, whichever first","Only two cross-references to external service bulletins (Piper and Purolator)","One conditional exemption (pilot replacement before effective date)","No nested definitions, no interpretive sections, no sub-delegations"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection of Facet air filter part no. 638873 (manufactured 1997–1998, white “FACET 638873” marking with no date code) on specified Piper PA‑24 Comanche 180/250/260 aircraft because filters have cracked and may shed debris into engines. Owners/operators must inspect installed filters at the next scheduled check or within 25 flight hours and every 25 hours thereafter, and inspect spares before installation. If a licensed (non‑student) pilot replaced the filter before the AD takes effect, the AD no longer applies to that aircraft."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope is narrowly targeted to the listed PA‑24 serial numbers and Facet P/N 638873 filters manufactured Jan 1997–Sept 1998. Note 2 provides that if an affected filter was removed from service before the directive’s effective date, the directive no longer applies to that aircraft. There is no expansion beyond the specified airframes, part number, and manufacture dates in the source text."},"complexity_factors":["Narrow, technical applicability: specific PA‑24 serial ranges and one Facet part number (P/N 638873) with manufacture dates Jan 1997–Sept 1998.","Identification requirement based on external branding (\"FACET 638873\" in 0.250\" white characters) and absence of a date code.","Recurrent inspection scheduling: initial inspection at next filter check or within 25 hours, then every 25 hours.","Different treatment for spares (inspection before installation) and installed units (recurring inspections).","Procedural dependence on external service bulletins (Piper SB No. 1022 and Purolator SB No. 090298.01) for inspection method.","Regulatory cross‑references and exceptions: CAR 42ZC(4)(d) permits pilot replacement; FAA AD 99‑05‑09 is referenced for context."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Piper PA‑24 aeroplanes to inspect certain Facet engine air inlet filters (P/N 638873, manufactured Jan 1997–Sept 1998) to prevent pieces of a deteriorating filter being ingested by the engine. Inspections must occur at the next filter check or within 25 hours and repeat every 25 hours; spare filters must be inspected before installation.\n\nThe compliance cost and operational burden fall on aircraft owners/operators and pilots; CAR 42ZC(4)(d) allows non‑student pilots to replace the filter, shifting labour responsibility away from maintenance organisations."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-24-45-engine-air-filter","history":"/api/acts/ad-pa-24-45-engine-air-filter/history","analysis":"/api/acts/ad-pa-24-45-engine-air-filter/analysis","conflicts":"/api/acts/ad-pa-24-45-engine-air-filter/conflicts","importantCases":"/api/acts/ad-pa-24-45-engine-air-filter/important-cases","documents":"/api/acts/ad-pa-24-45-engine-air-filter/documents"}}