{"id":"F2006B08515","name":"AD/CFM56/10 Amdt 1 - Stage 1-2 Spool HPC and No.3 Bearing Aft Stationary Air/Oil Seal","slug":"ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51249,"registerId":"commonwealth-F2006B08515-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CFM56/10 Amdt 1 - Stage 1-2 Spool HPC and No.3 Bearing Aft Stationary Air/Oil Seal","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)  \nCFM International Turbine Engines \\- CFM56 Series\n\nAD/CFM56/10\n\nAmdt 1\n\n  \n\nStage 1-2 Spool HPC and No.3 Bearing Aft Stationary Air/Oil Seal\n\n  \n10/98\n\nApplicability: CFM International (CFMI) CFM56-2 and CFM56-3, \\-3B and \\-3C model turbofan engines.\n\nRequirement: 1. CFM 56-2: Remove from service HPC stage 1-2 spool, part number 9992M60G07 having rubbing marks and with serial numbers as listed in manufacturers' Service Bulletin CFM56-2 No. 72-825, dated 23 January 1998 in accordance with the provisions of Service Bulletin CFM56-2, 72-825, and replace with a serviceable part.\n\n    2. CFM56-3, -3B, -3C: Remove from service HPC stage 1-2 spool part number 1589M66G02 with serial numbers listed in Service Bulletin CFM56-3/-3B/-3C 72- 856 dated 23 January 1998, in accordance with the provisions of Service Bulletin CFM56-3/3B/3C 72-856, and replace with a serviceable part.\n\n3. CFM56-3,-3B, \\-3C: Engines with serial numbers 856692, 856709, 856713,\n\n856799, 856673, 856691, 856694, 856696, 856697, 856746, 856780, 857669,\n\n857685, 857686, 857704 and 859115 carry out the following actions:\n\n    Remove from service the No. 3 bearing aft stationary oil seal part number 1663M91G03 and replace with a serviceable part, and\n\n    b. Install a No.3 bearing aft air/oil serial retention bushing in accordance with Service Bulletin CFM56-3/3B/3C No. 72-855 dated 23 June 1997.\n\nNote: For the purposes of this Airworthiness Directive, the following definitions apply:\n\n    (1) A serviceable spool is defined as a HPC1-2 spool without a rub or scratch indication.\n\n    (2) A serviceable seal is defined as a new No. 3 bearing aft stationary air/oil seal part number 1663M91G03 without one of the following serial numbers:\n\nCTD81631, CTD81907, CTD81908, CTD81998, CTD82004, CTD82132, CTD82208, CTD82210, CTD82212, CTD82213, CTD82271, CTD82295, CTD82297, CTD82298, CTD82300, CTD82304, CTD82457, CTD82759, CTD82766, CTD82767, CTD82788, CTD82817, CTD82822, CTD82854, CTD82855, CTD82856, CTD82857, CTD82859, CTD82962, CTD83232, CTD83474, CTD83837, CTD83839, CTD84100, CTD84138, CTD84140, CTD84141, CTD84143, CTD84144, CTD84145, CTD84148, CTD84203, CTD84206, CTD84207, CTD84258, CTD84262, CTD84360, CTD84363, CTD84604, CTD84712, CTD84741, CTD85147, CTD85148, CTD85149, CTD85161, CTD85162, CTD85166, CTD85168, CTD85169, CTD85170, CTD85172, CTD85348, CTD85349, CTD85351, CTD85352, CTD85353, CTD85354, CTD85355.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nCompliance: 1. At the next exposure of the spool after the effective date of this directive, but prior to accumulating 2000 cycles since the last shop visit associated with the rub event.\n\n    2. As per 1 above.\n\n    3. Prior to 1 May 1998.\n\nNote: DGAC AD 98-080(B)R1 dated 17 June 1998 refers.\n\nThis amendment does not effect the compliance requirements of the initial issue. This amendment becomes effective on 10 September 1998.\n\nBackground: Several separations of No. 3 bearing aft stationary air/oil seal have been experienced in service, resulting in rubbing on the disk of high pressure compressor spool stage 1-\n\n2. To prevent the effects due to seal separation and rubbing, this directive mandates the removal and replacement of certain spools and seals. This revision is to correct some typing errors in Requirement paragraph 3b, note (2).\n\nThe original issue of this airworthiness directive became effective on 1 April 1998.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The amendment corrects typographical errors in the original directive (paragraph 3b, Note (2)) and explicitly states it does not affect the original compliance requirements; therefore the scope of affected engines, parts and required actions remains unchanged."},"complexity_factors":["Multiple engine models covered (CFM56-2, -3, -3B, -3C) increasing applicability scope (Applicability).","Action tied to specific part numbers and a long list of serial numbers for seals and spools (Requirement; Note (2)).","Work must follow manufacturer Service Bulletins which prescribe inspection/replace procedures (Requirement references to SB CFM56-2 72-825, CFM56-3/3B/3C 72-856 and 72-855).","Staged compliance windows (next exposure of spool, prior to 2000 cycles since last shop visit, or by 1 May 1998) create conditional timing obligations (Compliance).","Definitions of “serviceable” parts narrow acceptable replacements and create a parts-tracking burden (Note (1) and Note (2)).","Some requirements apply only to engines with specific serial numbers, producing asymmetric burden across operators (Requirement 3).","Cross-reference to foreign AD (DGAC AD 98-080(B)R1) and prior ADs adds regulatory tracing for operators and regulators (Note).","Amendment states it only corrects typographical errors and does not change compliance requirements, reducing substantive legal change but requiring attention to text corrections (Background)."],"plain_english_summary":"This Airworthiness Directive obliges operators of CFM56-2 and CFM56-3/-3B/-3C engines to remove and replace specified HPC stage 1‑2 spools and certain No.3 bearing aft stationary air/oil seals (identified by part and serial numbers) and to install a retention bushing on listed engines, following the manufacturer's service bulletins. The stated aim is to prevent seal separations and rubbing that can damage the compressor spool; compliance is required at the next exposure or by 1 May 1998. The amendment corrects typographical errors and does not change compliance obligations."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a minor amendment (Amendment 1) that explicitly states it 'does not effect the compliance requirements of the initial issue.' The scope remains limited to the specific safety issue of No. 3 bearing seal separations and resulting HPC spool rubbing. The amendment only corrects typing errors in Requirement paragraph 3b and note (2)."},"complexity_factors":["Multiple overlapping applicability rules (different engine models trigger different requirements)","Extensive serial number lists (16 engine serials in Requirement 3, 67 seal serials in Note 2)","Cross-references to manufacturer Service Bulletins (CFM56-2 SB 72-825, CFM56-3 SB 72-856, SB 72-855)","Conditional compliance deadlines ('next exposure' vs fixed calendar date)","Nested definitions ('serviceable' defined negatively by exclusion of specific serial numbers)","Technical aviation terminology requiring specialised knowledge (HPC spool, air/oil seal, retention bushing, shop visit, cycles)"],"plain_english_summary":"This CASA Airworthiness Directive mandates removal/replacement of certain damaged high-pressure-compressor spools and defective No. 3 bearing seals on CFM56-2/-3/-3B/-3C engines. It affects airlines, operators and maintenance organisations using these engines and aims to prevent spool rubbing and possible engine damage or loss of power. Amendment 1 corrects typos from the April 1998 AD but does not change the required corrective actions."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal","history":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal/history","analysis":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal/analysis","conflicts":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal/conflicts","importantCases":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal/important-cases","documents":"/api/acts/ad-cfm56-10-amdt-1-stage-1-2-spool-hpc-and-no-3-bearing-aft-stationary-air-oil-seal/documents"}}