{"id":"F2006B02322","name":"AD/ALF/8 Amdt 1 - Introduction of Turbine Spacers P/N 2-121-071-31/35","slug":"ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41552,"registerId":"commonwealth-F2006B02322-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ALF/8 Amdt 1 - Introduction of Turbine Spacers P/N 2-121-071-31/35","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)  \nAlliedSignal (Lycoming) Turbine Engines \\- ALF502 and LF507 Series\n\nAD/ALF/8\n\nAmdt 1\n\n  \nIntroduction of Turbine Spacers P/N 2-121-071-31/35 4/88\n\nApplicability: ALF 502R series engines prior to S/N LF05424. Requirement: Install improved turbine spacers P/N 2-121-071-31/35.\n\nCompliance: Unless already accomplished in accordance with the schedule and procedure detailed in Lycoming SB ALF 502R-72-0163 dated 8 June 1987 or a schedule acceptable to the Secretary.\n\nNote 1: FAA AD 87-15-03 Amdt 39-5660 refers.\n\nNote 2: Installation of other P/N improved spacers, for these engines, which are listed in Lycoming S.B. ALF 502-72-0002 Rev 17 (or later) and whose cyclic lives are greater than those of P/Ns 2-121-071-31/35, renders compliance with this Directive unnecessary - AD/ALF/2 Amdt 3 refers.\n\nBackground: This Directive is amended to note and reference LYC SB ALF 502-72-0002 Rev 17, (and AD/ALF/2 Amdt 3) which lists other acceptable P/N spacers which when fitted makes compliance with this Directive unnecessary.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment adds and references Lycoming SB ALF 502-72-0002 Rev 17 and AD/ALF/2 Amdt 3 (see Note 2 and Background). That change creates an alternative compliance route: if an engine is fitted with other improved spacers listed in that SB with cyclic lives greater than P/N 2-121-071-31/35, the mandatory requirement to install P/N 2-121-071-31/35 no longer applies. The amendment therefore narrows the set of engines that must fit the specified P/N, without extending applicability beyond the original serial-number cut-off or altering the installation procedures referenced."},"complexity_factors":["Targeted applicability: applies only to ALF502R engines with serial numbers prior to LF05424 (straightforward but narrow scope).","Single technical action: mandate to install a specific P/N spacer (clear mechanical remedy).","Alternative compliance path: permits fitting other spacers listed in Lycoming SB ALF 502-72-0002 Rev 17 (or later) with greater cyclic life, which removes the need to fit the specified P/N (adds conditional logic).","Dependence on external technical documents: compliance references Lycoming SB ALF 502R-72-0163 and SB ALF 502-72-0002 Rev 17, requiring operators to obtain and follow those documents.","Regulatory discretion: a schedule 'acceptable to the Secretary' allows the regulator to approve different timing or methods (administrative discretion).","Cross-references: notes refer to FAA AD 87-15-03 and AD/ALF/2 Amdt 3, creating interlocking obligations to check related directives."],"plain_english_summary":"This Airworthiness Directive requires operators of AlliedSignal (Lycoming) ALF502R engines (serial numbers before LF05424) to fit improved turbine spacers P/N 2-121-071-31/35, following Lycoming service bulletin ALF 502R-72-0163 (8 June 1987) or a schedule acceptable to the Secretary. It allows an alternative: fitting other improved spacers listed in Lycoming SB ALF 502-72-0002 Rev 17 (or later) with greater cyclic life, in which case this AD need not be complied with. Operators pay for parts and labour; the regulator may accept alternative compliance schedules."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 1 to an existing directive. The amendment simply adds a cross-reference to an alternative compliance method (other part numbers listed in a later service bulletin). The core scope — requiring improved turbine spacers for specific engines — remains unchanged. The amendment makes compliance easier by recognizing equivalent or superior alternatives, but does not expand the safety issue or add new requirements."},"complexity_factors":["Single, specific technical requirement (install specific part numbers)","Limited applicability (only ALF 502R series engines before serial number LF05424)","Two alternative compliance paths (original SB or Secretary-approved schedule)","Cross-reference to another Australian AD (AD/ALF/2 Amdt 3) for alternative parts","Reference to US FAA AD for international alignment","No defined terms section or extensive interpretation provisions","Short, single-purpose instrument (approximately 200 words)"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires operators of AlliedSignal (Lycoming) ALF 502R engines (serial numbers before LF05424) to fit improved turbine spacers (part numbers 2-121-071-31 or 2-121-071-35) to address a spacer safety/failure risk.  \n\nIt matters because installing the stronger spacers (or approved equivalents) prevents potential engine failure and keeps affected aircraft airworthy."}},"importantCases":[],"_links":{"self":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35","history":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35/history","analysis":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35/analysis","conflicts":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35/conflicts","importantCases":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35/important-cases","documents":"/api/acts/ad-alf-8-amdt-1-introduction-of-turbine-spacers-p-n-2-121-071-31-35/documents"}}