{"id":"F2006B02438","name":"AD/APU/5 Amdt 2 - Cooling Fan Assembly","slug":"ad-apu-5-amdt-2-cooling-fan-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41694,"registerId":"commonwealth-F2006B02438-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/APU/5 Amdt 2 - Cooling Fan Assembly","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAuxiliary Power Units\n\nAD/APU/5\n\nAmdt 2\n\n  \nCooling Fan Assembly 5/89\n\nApplicability: All GTEC models GTCP 331-200A, \\-200AC, \\-200C, \\-200ER, \\-250F, \\-250H, and \\- 200P APUs with fan assembly PN 3862160-3, -4 and 5.\n\nRequirement: Part 1: Garrett Turbine Engine company Service Bulltetin GTCP 331-49-5546 Rev 2.\n\nNote: FAA AD 85-14-02 R2 Part A Refers.\n\nPart 2: Garrett Service Bulletin 3862160-49-5716 Revision 1.\n\nNote: FAA AD 85-14-02 R2 Part B Refers.\n\nCompliance: Part 1: Within 100 aircraft flight hours after 30 September 1985 but not later than 31 October 1985.\n\nPart 2: At the next removal of modified cooling fan assy PN 3862160-5 for any reason or within 6 months after 18 May 1989 whichever is the sooner.\n\nBackground: Part 1 of this Directive incorporates a new fan assembly with an improved fan containment housing. Following 3 instances of uncontained failures of the modified fan assembly, changes to the fan housing and containment ring assembly attachment have been made. This Directive is amended to reflect FAA AD 85-14-02 R.2 Part B dated 22 February 1989 and Garrett Service bulletin 3862160-49-5716 which further modifies the APU with cooling fan P/N 3862160-5 fitted.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment expands and clarifies required modifications to include further changes to APUs fitted with cooling fan PN 3862160‑5, aligning the Directive with FAA AD 85‑14‑02 R.2 Part B and Garrett Service Bulletin 3862160‑49‑5716 (Background; Requirement Part 2)."},"complexity_factors":["Technical specificity: applies only to listed GTCP 331 APU models and particular fan assembly part numbers (Applicability).","Dual mandated actions: two separate service-bulletin requirements (Requirement: Part 1 and Part 2) with different triggers.","Mixed compliance triggers: a fixed flight‑hour deadline for one action and a time‑or‑removal trigger for the other (Compliance).","External references: incorporates manufacturer service bulletins and cross‑references FAA AD 85‑14‑02 R2, requiring implementers to consult external documents (Requirement, Note).","Operational scheduling burden: maintenance planners must track hours, removal events, and a calendar deadline to determine when to modify units (Compliance).","Safety‑critical engineering change: modifications affect fan containment and attachment design, raising parts availability and technical installation considerations (Background)."],"plain_english_summary":"This airworthiness directive requires owners/operators of GTEC GTCP 331-series APUs fitted with cooling fan assemblies PN 3862160-3, -4 or -5 to carry out mandated Garrett service-bulletin modifications to the fan housing and containment ring to address uncontained fan failures. Compliance is either time‑based or triggered at next removal, so operators pay for parts and maintenance; the Civil Aviation Safety Authority enforces the two service bulletins referenced (see Requirement, Compliance, Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays tightly within the original scope of AD/APU/5. It adds Part 2 to address a specific failure mode discovered after Part 1 was implemented, but does not expand to new APU models, new failure types, or broader operational requirements. The amendment is a targeted response to new safety data rather than scope creep."},"complexity_factors":["Short, single-purpose document (2 pages)","Only 7 defined model variants and 3 part numbers in scope","Simple two-part compliance structure with clear deadlines","Minimal cross-referencing (only to FAA AD 85-14-02 R2 and two manufacturer service bulletins)","No nested exceptions or conditional logic beyond standard 'whichever is sooner' timing clause","Straightforward background explanation linking failures to required action"],"plain_english_summary":"This CASA Airworthiness Directive orders urgent safety modifications to certain GTEC APUs (GTCP 331‑200A/‑200AC/‑200C/‑200ER and GTCP 250F/‑250H/‑200P) fitted with the specified cooling fan part to prevent uncontained fan failures. An earlier containment-housing fix (due Oct 1985) proved insufficient; this amendment mandates further housing and containment‑ring modifications after fan removal or within six months of May 1989. It applies to aircraft operators and maintenance organisations responsible for those APUs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly","history":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly/history","analysis":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly/analysis","conflicts":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly/conflicts","importantCases":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly/important-cases","documents":"/api/acts/ad-apu-5-amdt-2-cooling-fan-assembly/documents"}}