{"id":"F2011L01782","name":"AD/B737/52 Amdt 3 - Corrosion Prevention and Control Program (CPCP)","slug":"ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":87077,"registerId":"commonwealth-F2011L01782-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/52 Amdt 3 | Corrosion Prevention andControl Program (CPCP) | 18/2011 |\n| ----------------- | ---------------------------------------------- | ------- |\n\n| Applicability: | All Model 737 series aeroplanes; unless the system of maintenance includes an alternative method of compliance approved by CASA.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 90-25-01 Amdt39-6789.Corrosion classified as level 1 need not be reported. Level 2 corrosion may be consolidated with a sixty day report of corrective action, and submitted to CASA under cover of a single SDR. Level 3 corrosion shall be reported by SDR.Note 1: Boeing document No. D6-38528 at latest revision is associated with FAA AD 90-25-01.Note 2: Boeing 737-300/400/500 Maintenance Planning Data Document No D6-38278 Section 10 at latest revision is an approved Alternative Method Of Compliance (AMOC) to this AD.Note3: FAA Letter 120S-09-687, dated February 04, 2010 is associated with FAA AD 90-25-01.Note 4: Boeing 737-600/-700/-700C/-800/-900/-900ER CPCP program is included in the Maintenance Review Board Report and the Maintenance Planning Data Documents. As such an AMOC to FAA AD 90-25-01 has been approved under the conditions of FAA Letter 120S-09-687, and is approved as an AMOC to this AD.Note 5 : References made in the FAA AD text to the following:Administrator,FAA,FAA Principal Inspector (PI), orManager Seattle Certification Office (ACO)shall be read as Civil Aviation Safety Authority Office. |\n| Compliance:    | As specified in the Requirement Document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n\n|             | This Amendment becomes effective on 5 September 2011.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Background: | The Country of Origin Airworthiness Authority requires implementation of a corrosion prevention and control program to prevent the degradation of the structural capabilities of the affected aircraft.Amendment 1 was raised to specify the reporting requirements when corrosion is found as a result of the CPCP.Amendment 2 was issued to introduce a method of compliance other than the Country of Origin AD, to address current \"in production\" aircraft.Amendment 3 is issued to introduce a method of compliance for 737-600/-700/-700C/-800/-900/-900ER aircraft. |\n\n![](image.001.png)  \nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n26 August 2011","sortOrder":0},{"sectionNumber":"AD/B737/52 Amdt 3","sectionType":"part","heading":"AD/B737/52 Amdt 3","content":"## AD/B737/52 Amdt 3","sortOrder":1},{"sectionNumber":"Corrosion Prevention andControl Program ","sectionType":"part","heading":"Corrosion Prevention andControl Program (CPCP)","content":"## Corrosion Prevention and  \nControl Program (CPCP)","sortOrder":2},{"sectionNumber":"18/2011","sectionType":"part","heading":"18/2011","content":"## 18/2011","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"The AD's scope has been broadened through successive amendments. Amendment 1 specified corrosion reporting requirements; Amendment 2 introduced an approved alternative method of compliance for in‑production aircraft; Amendment 3 added an AMOC pathway for 737-600/-700/-700C/-800/-900/-900ER aircraft by accepting MRB/MPD material. These changes expand acceptable compliance methods and explicitly include additional 737 variants (Background; Requirement Notes 2–4)."},"complexity_factors":["Applicability covers all Model 737 series aeroplanes but allows alternatives only if approved by CASA, creating a fleet-wide requirement with case-by-case exemptions (Applicability).","Requirement cross‑references FAA AD 90-25-01 and associated Boeing documents, meaning compliance depends on external, technical documents not reproduced in the AD (Requirement; Note 1).","Corrosion reporting is tiered: Level 1 need not be reported; Level 2 may be consolidated with a 60‑day corrective-action report; Level 3 must be reported by a Service Difficulty Report (SDR) — this creates distinct inspection and administrative workflows (Requirement).","Multiple AMOCs are explicitly accepted (Boeing D6-38278 MPD, Boeing D6-38528, FAA Letter 120S-09-687, and MRB/MPD for 737-600/-700/-800/-900 series), so operators must determine which external document applies and ensure its latest revision is used (Requirement Notes 1–4).","The AD remaps FAA authority references to CASA, concentrating approval and interpretation discretion with CASA (Note 5).","Compliance is stated as 'As specified in the Requirement Document', which delegates substantive procedural detail and timing to the referenced materials and increases reliance on up‑to‑date external documents (Compliance / Requirement).","Amendment history (Amendments 1–3) expanded reporting rules and acceptable AMOCs and extended explicit coverage to later 737 variants, adding historical complexity for operators tracking applicable versions (Background).","Operational and administrative burden falls on aircraft operators: performing CPCP actions, maintaining records, and submitting SDRs where required (Applicability; Requirement)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737 series aeroplanes to follow a corrosion prevention and control program (CPCP) and to report corrosion findings according to set levels. It binds operators to the technical requirements of FAA AD 90-25-01 unless CASA has approved an alternative method of compliance (AMOC).\n\nIt matters because operators must carry out inspections, corrective work and specified reporting to CASA, and certain Boeing maintenance documents and FAA letters are accepted as approved alternatives."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original directive (implied by Amendment 1 and 2 references) appears to have covered older 737 models (-300/-400/-500 series). Amendment 3 significantly expanded scope to include the newer 'Next Generation' variants (-600/-700/-800/-900 series and the -700C/-900ER sub-variants). The Background section explicitly states Amendment 3 was issued specifically to introduce compliance methods for these additional aircraft types, effectively doubling the covered fleet."},"complexity_factors":["Multiple nested document references (FAA AD 90-25-01, Boeing D6-38528, D6-38278, FAA Letter 120S-09-687) requiring cross-referencing to understand full requirements","Conditional logic for three-tier corrosion reporting system (Level 1/2/3) with different timeframes and consolidation rules","Multiple applicability exceptions based on aircraft model variants (737-300/400/500 vs 737-600/-700/-700C/-800/-900/-900ER) with different compliance pathways","Substitution of US regulatory terms for Australian context (Administrator/FAA/Principal Inspector → CASA Office)","Incorporation by reference of external technical documents rather than spelling out requirements in the text itself"],"plain_english_summary":"This AD requires all Boeing 737 operators in Australia to implement a Corrosion Prevention and Control Program so corrosion is proactively monitored and fixed rather than discovered by failure. It classifies corrosion into three reporting tiers (minor, moderate, serious) with escalating reporting duties, affects airlines and maintenance organisations, and allows CASA‑approved alternative compliance methods. Corrosion control protects structural integrity and safety."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp","history":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp/history","analysis":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp/analysis","conflicts":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp/conflicts","importantCases":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp/important-cases","documents":"/api/acts/ad-b737-52-amdt-3-corrosion-prevention-and-control-program-cpcp/documents"}}