{"id":"F2006B02312","name":"AD/ALF/16 Amdt 1 - Fan Core Inlet Anti-Ice System","slug":"ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41542,"registerId":"commonwealth-F2006B02312-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ALF/16 Amdt 1 - Fan Core Inlet Anti-Ice System","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)  \n![](image.002.png)  \nAlliedSignal (Lycoming) Turbine Engines \\- ALF502 and LF507 Series\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.003.png)For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ALF/16 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nApplicability: ALF502R series engines.\n\n![](image.004.png)Requirement: Incorporate fan core inlet anti-ice system modifications in accordance with AlliedSignal Service Bulletin ALF/LF 72-1020, Revision 3, dated 19 January 2001.\n\nNote 1: Compliance with SB ALF/LF 72-1020, Revision 2, dated 30 September 1998, satisfies the intent of this amendment to the AD.\n\nNote 2: FAA AD 99-15-06 refers.\n\nNote 3: AD/BAe146/75 addresses the requirements when installing modified engines on BAe 146 series aircraft.\n\nCompliance: During any shop visit for scheduled hot section inspection, not to exceed 10,000 cycles in service after the effective date of this airworthiness directive, but no later than 31 December 2003.\n\nThis Amendment becomes effective on 12 July 2001.\n\nBackground: ALF502 engines installed on BAe146 aircraft are prone to a phenomenon known as “rollback” which is an uncommanded power reduction condition and loss of thrust control in certain icing conditions. There have been instances where simultaneous rollback occurred on multiple engines on the same aircraft.\n\n![](image.005.png)This amendment references Revision 3 of SB ALF/LF 72-1020 that updates procedures and parts in universal Installation Kit, Part No. 2-203-930-05, detail part numbers.\n\nThe original issue of this Airworthiness Directive became effective on 4 November 1999.\n\n![](image.006.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority\n\n1 June 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 13 June 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment updates the referenced Service Bulletin to Revision 3 and clarifies procedures and part numbers for the fan core inlet anti‑ice modification but keeps the applicability limited to ALF502R series engines. Note 1 explicitly states that compliance with Revision 2 also satisfies the AD, so the safety requirement and affected population are not expanded beyond the original AD."},"complexity_factors":["Single, targeted technical requirement tied to a manufacturer Service Bulletin (ALF/LF 72-1020 Revision 3).","Conditional compliance timing: during next scheduled hot-section inspection, not to exceed 10,000 cycles after the AD effective date, or by a fixed calendar date (31 December 2003).","Cross-references to other regulatory instruments (FAA AD 99-15-06 and AD/BAe146/75) that affect installation context on specific airframes.","Revocation and replacement of an earlier AD, plus a note that compliance with an earlier SB revision (Revision 2) also satisfies intent — requires attention to which SB revision was used.","Update to parts list and universal installation kit detail part numbers in the referenced SB (affects procurement/maintenance planning)."],"plain_english_summary":"This Airworthiness Directive (AD) requires operators of AlliedSignal (Lycoming) ALF502R turbofan engines to install a fan-core inlet anti‑ice system modification by following AlliedSignal Service Bulletin ALF/LF 72‑1020 Revision 3. CASA issued the AD to address ‘‘rollback’’ — an uncommanded power reduction and loss of thrust control in certain icing conditions. Operators must carry out the modification at the next scheduled hot‑section inspection (within 10,000 cycles or by 31 December 2003). Engine owners pay for parts and installation; CASA enforces compliance by mandating the SB procedures."},"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 amendment maintains the original scope of AD/ALF/16 (first issued 4 November 1999). It updates the technical implementation details to reference a revised service bulletin (Revision 3 instead of Revision 2) but does not expand the applicability to new engine types, introduce new safety concerns, or alter the fundamental purpose of the directive. The amendment is a technical refinement within the original safety intent."},"complexity_factors":["Single, clearly defined applicability (ALF502R series engines only)","Straightforward compliance trigger (shop visit for hot section inspection OR hard deadline)","Minimal cross-referencing (3 notes referencing related documents, but not creating conditional obligations)","No nested exceptions or conditional logic — requirement applies uniformly to all affected engines","Short, single-purpose document (approximately 300 words of substantive text)","Technical content is specific but not legally convoluted (references to service bulletins and part numbers are standard aviation practice)"],"plain_english_summary":"This CASA safety order mandates installation of an upgraded fan-core inlet anti-ice system on AlliedSignal/Lycoming ALF502R engines (used mainly on BAe 146) to prevent ice-induced \"rollback\" power loss. It affects aircraft operators and maintenance organisations performing overhauls.\n\nThe modification must be done per AlliedSignal SB ALF/LF 72-1020 Rev 3 at the next hot-section inspection or by 10,000 flight cycles / 31 Dec 2003, whichever is earlier. Effective 12 July 2001; this replaces the earlier AD/ALF/16."}},"importantCases":[],"_links":{"self":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system","history":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system/history","analysis":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system/analysis","conflicts":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system/conflicts","importantCases":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system/important-cases","documents":"/api/acts/ad-alf-16-amdt-1-fan-core-inlet-anti-ice-system/documents"}}