{"id":"F2006B08528","name":"AD/CFM56/3 Amdt 1 - Number Three Bearing","slug":"ad-cfm56-3-amdt-1-number-three-bearing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51284,"registerId":"commonwealth-F2006B08528-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CFM56/3 Amdt 1 - Number Three Bearing","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/CFM56/3\n\nAmdt 1\n\n  \n\nNumber Three Bearing 3/90 DM\n\nApplicability: CFM56-3, \\-3B, \\-3C, \\-5 series engines.\n\nRequirement: 1. Inspect the forward sump magnetic plug chip detector, for evidence of contamination, and\n\n    2. If contamination is evident on the forward sump magnetic plug chip detector, determine magnitude, source of contamination, and action in accordance with;\n\n    (a) Boeing CFM 737-300/400 Maintenance Manual D6-37588-388 Chapter 79- 00-00, Para 5, or\n\n    (b) Airbus A320 Aircraft Maintenance Manual Rev. 8 Chapter 79-21-10, or\n\n    (c) As agreed by the Authority.\n\nCompliance:\n\n  \n\n    Effective 7 February 1990, inspect at intervals not to exceed;\n\n    (a) CFM56-3, 3B, 3C series engines equipped with Number 3B bearings, part number 9732M1OP12 serial number series FAFDxxxx or FAFExxxx with less than 6000 hours bearing TSN; 50 hours time in service.\n\nNote: P/N 9732M1OP12 bearings which have achieved 6000 hours TSN or greater are exempt from the inspection requirements of this Directive.\n\n    (b) CFM56-3, 3B, 3C series engines equipped with Number 3B bearings, part numbers 9732M1OP18 or 1362M76P02; 50 hours time in service.\n\n    (c) CFM56-3, 3B, 3C series engines equipped with Number 3B bearings, part numbers 9732M10P10; 9732M10P17; and 9732M10P12 serial number series other than FAFDxxxx or FAFExxxx, with less than 6000 hours bearing TSN; 75 hours time in service.\n\nNote: P/N 9732M10P10, 9732M10P17 and 9732M10P12 bearings which have achieved 6000 hours TSN or greater are exempt from the inspection requirements of this Directive.\n\n    (d) CFM56-5 series engines equipped with Number 3B bearings, part number 9542M60P01; 50 hours time in service.\n\nFor the purpose of this Directive, a planning tolerance of 5 hours is permitted for inspection intervals listed in 1(a), 1(b), 1(c), 1(d) provided operator inspection schedules reflect the listed inspection intervals of this Directive.\n\n    2. Before further flight.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: This Directive has been amended to;\n\n    Increase the applicability requirements of this Directive to include all CFM 56-3, 3B, 3C series engines regardless of bearing part number or bearing serial number.\n\n    2. Include the CFM56-5 series.\n\n    3. Delete the requirement to replace certain bearings by part number or serial number.\n\n    4. Reflect advice received from the manufacturer of in-service data which supports an alleviation of the inspection requirement for certain bearings by part number upon achieving 6000 hours time in service.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. Compared with the earlier version, this amendment broadened scope and altered obligations: (1) it expanded applicability to include all CFM56-3 series engines irrespective of bearing part or serial number, (2) it added CFM56-5 series engines, (3) it removed a prior mandatory replacement requirement for certain bearings, and (4) it introduced an exemption from inspections for specified bearing part numbers once those bearings reach 6,000 hours TSN — the exemption based on manufacturer in-service data. These changes both widen the population of engines/bearings subject to inspection and carve out a time-based exemption for some bearings."},"complexity_factors":["Multiple engine models covered (CFM56-3, -3B, -3C, and -5) increasing applicability","Several distinct bearing part numbers grouped differently in compliance paragraphs (4 distinct groupings)","Conditional exemptions based on bearing TSN (>= 6,000 hours) for certain part-number groups","Two different inspection intervals (50 hours and 75 hours) plus a 5-hour planning tolerance","Immediate mandatory action clause (“Before further flight”) creating a zero-tolerance operational trigger","Cross-references to external documents (Boeing and Airbus maintenance manuals) for corrective procedures","Ability to substitute procedures with CASA agreement introduces regulatory discretion","Background amendment history changes scope (see scope_assessment)"],"plain_english_summary":"**What this Directive does (mechanical change)**\n\n- Requires operators of aircraft with CFM International CFM56 engines (CFM56-3, -3B, -3C and -5 series) to inspect the forward sump magnetic plug (a magnetic chip detector in the oil sump) for contamination at regular, short intervals. (Requirement 1)\n- If contamination is found, operators must determine how much contamination there is, where it came from, and take the corrective action set out in the aircraft manufacturer maintenance manual (Boeing or Airbus), or in an alternative procedure agreed with the Civil Aviation Safety Authority (CASA). (Requirement 2 and subparagraphs (a)–(c))\n- If contamination is detected that creates an unsafe condition, the engine must not fly until appropriate corrective action has been taken (“Before further flight”). (Requirement 2)\n\n**Exactly who inspects, when, and which engines/bearings are covered**\n\n- Applies to CFM56-3/-3B/-3C engines and CFM56-5 engines fitted with certain Number 3 (3B) bearings. The directive lists specific bearing part numbers and, for some serial number series, applies only while the bearing has less than 6,000 hours time-since-new (TSN). (Compliance paragraphs (a)–(d))\n- Inspection intervals depend on the bearing part number/serial group:\n  - 50 hours time in service for most listed bearings (see 1(a), 1(b), 1(d)).\n  - 75 hours time in service for one set of part-numbered bearings listed in 1(c).\n- A planning tolerance of 5 hours is allowed when scheduling these inspections.\n- Bearings that have reached 6,000 hours TSN (for the part numbers so identified) are exempt from the inspection requirement. (Notes under 1(a) and 1(c))\n\n**Where to find corrective procedures**\n\n- If contamination is found, the directive refers operators to the Boeing or Airbus maintenance manual chapters cited (or to procedures agreed by CASA) for how to assess magnitude and effect and what corrective steps to take. (Requirement 2(a)–(c))\n\n**Official rationale supplied in the text**\n\n- The amendment broadens the group of engines/bearings covered (to include all CFM56-3 variants regardless of bearing PN/serial and to add CFM56-5), removes earlier mandatory replacement requirements for specific bearings, and introduces an exemption from inspections for certain bearings once they reach 6,000 hours TSN — based on manufacturer in-service data. (Background points 1–4)\n\nAnalysis: costs, incentives, trade-offs, and implementation mechanics\n\n- Who pays: aircraft operators/owners pay for the inspections (labour, possible downtime) and any follow-up maintenance or part replacement if contamination is found.\n- Who decides: operators must follow the Boeing/Airbus maintenance manual procedures cited or obtain CASA agreement for an alternative. CASA retains discretion to accept alternative actions. (Requirement 2 and subparagraphs)\n- Behaviour change required: operators must increase the frequency of sump magnetic plug inspections (every 50–75 flight hours depending on the bearing fitted) and track bearing part numbers and TSN to determine whether an engine/bearing is in scope or exempt.\n- Compliance burden: frequent, recurring inspections at short flight-hour intervals will increase maintenance activity and recordkeeping. Tracking TSN for specific part-number/serial groups is necessary to apply the 6,000-hour exemption correctly. If contamination is found, operators must follow potentially complex diagnostic and corrective procedures from the airframe/engine manufacturer.\n- Trade-offs and incentives: the rule prioritises early detection of bearing wear/contamination through frequent inspections. The 6,000-hour exemption (for some bearing types) reduces long-term inspection burden for those bearings; that exemption is based on manufacturer in‑service data as noted in the Background. That creates an incentive to monitor TSN accurately; it may also influence fleet maintenance choices (how long a bearing is kept in service) because inspection burden changes at the 6,000‑hour mark.\n- Implementation risk and ambiguity: the directive requires operators to determine the “magnitude” and “source” of contamination — that judgment relies on manufacturer manual procedures or CASA agreement and may allow variation between operators. Cross-references to Boeing and Airbus manuals mean the exact corrective steps are not contained in this directive and rely on the accessibility and interpretation of those manuals.\n\nPractical takeaway\n\n- If you operate aircraft with CFM56-3/-3B/-3C or CFM56-5 engines, check which Number 3 bearing part number and serial range you have, track its TSN, and schedule sump magnetic plug inspections every 50–75 flight hours as specified. If contamination appears, follow the cited aircraft maintenance manual procedures or get an agreed alternative from CASA, and do not continue flying until the defect is addressed."},"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":4,"scope_assessment":{"changed":true,"description":"The amendment significantly expanded the original directive's scope. Originally focused on specific bearing part numbers and serial numbers requiring replacement, the amended version: (1) broadened applicability to cover ALL CFM56-3/3B/3C engines regardless of bearing specifications, (2) added an entirely new engine series (CFM56-5), and (3) removed mandatory replacement requirements in favour of inspection-based compliance. However, it simultaneously narrowed operational burden by introducing exemptions for high-time bearings (6,000+ hours) based on manufacturer service data."},"complexity_factors":["Multiple conditional inspection intervals based on four different bearing part number categories (1a-1d)","Nested exemption criteria (6,000 hours TSN threshold varies by part number and serial number series)","Cross-references to external technical documents (Boeing and Airbus maintenance manuals)","Specific serial number ranges (FAFDxxxx/FAFExxxx) creating additional categorisation","Technical aviation terminology requiring domain knowledge (TSN = Time Since New, magnetic plug chip detector, forward sump)","Planning tolerance exception (5-hour buffer) adding a conditional modifier to all intervals"],"plain_english_summary":"This CASA safety directive requires airlines and maintenance crews operating CFM56-3/-3B/-3C/-5 engines (Boeing 737 and Airbus A320 families) to inspect forward-sump magnetic chip detectors for metal contamination that can signal Number Three Bearing failure. \n\nInspections must follow manufacturer guidance with intervals varying by bearing type and hours flown (some bearings inspected more frequently; bearings with 6,000+ hours are exempt). The goal is early detection of bearing wear to prevent catastrophic engine failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing","history":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing/history","analysis":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing/analysis","conflicts":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing/conflicts","importantCases":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing/important-cases","documents":"/api/acts/ad-cfm56-3-amdt-1-number-three-bearing/documents"}}