{"id":"F2008L00704","name":"AD/B737/317 - Section 48 cavity","slug":"ad-b737-317-section-48-cavity","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":72742,"registerId":"commonwealth-F2008L00704-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/B737/317 | Section 48 cavity | 5/2008 DM |\n| ----------- | ----------------- | --------- |\n\n| Applicability: | Boeing Model 737-600, 737-700, 737-700C, 737-800 and 737-900 series aircraft as identified in Boeing Service Bulletin 737-53A1242, Revision 2, dated 23 April 2007.                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2008-05-05 Amdt 39-15399.Note: Boeing Service Bulletin 737-53A1242, Revision 2, dated 23 April 2007 or later revision approved by the FAA refers.                                                                                                                        |\n| Compliance:    | Within 2,500 flight cycles or 18 months after the effective date of this AD, whichever occurs first.                                                                                                                                                                                                                                    |\n|                | This Airworthiness Directive becomes effective on 8 April 2008.                                                                                                                                                                                                                                                                         |\n| Background:    | This AD is raised due to reports that moisture was found within the Section 48 cavity. This AD requires inspection of various locations in Section 48 for the correct application of sealant and also for signs of corrosion on the flight control cables, fittings, pulleys, horizontal stabiliser jackscrew, ballnut and gimbal pins. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n6 March 2008","sortOrder":0},{"sectionNumber":"AD/B737/317","sectionType":"part","heading":"AD/B737/317","content":"## AD/B737/317","sortOrder":1},{"sectionNumber":"48","sectionType":"part","heading":"cavity","content":"## Section 48 cavity","sortOrder":2},{"sectionNumber":"5/2008 DM","sectionType":"part","heading":"5/2008 DM","content":"## 5/2008 DM","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrowly-targeted Airworthiness Directive addressing a specific safety issue (moisture ingress in Section 48 cavity) on specific aircraft models. The scope remains tightly focused on the original safety concern without expansion into unrelated areas."},"complexity_factors":["Very short document (approximately 200 words of substantive content)","Only 1 defined term implicitly referenced (Section 48 cavity — location on aircraft)","No nested conditional logic or exceptions","Single compliance pathway with clear deadline calculation","Cross-reference to one external technical document (FAA AD 2008-05-05 and Boeing Service Bulletin 737-53A1242 Rev 2)","Simple binary applicability test (aircraft model identification)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections on Boeing 737-600/700/700C/800/900 Next Generation aircraft. It affects owners/operators of those models and adopts the FAA’s technical requirements.\n\nOperators must inspect Section 48 for correct sealant application and corrosion on flight control cables, fittings/pulleys, the horizontal stabiliser jackscrew/ballnut and gimbal pins to prevent moisture-induced control failures. Compliance was required within 2,500 flight cycles or 18 months after 8 April 2008."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The AD sets out inspections and corrective actions for the specific Boeing 737 models identified in the referenced Boeing service bulletin and requires compliance per the referenced FAA AD within the stated timeframe. The instrument itself does not indicate any expansion or reduction of that applicability beyond the listed models and referenced documents."},"complexity_factors":["Incorporation by reference of FAA AD 2008-05-05 and Boeing Service Bulletin 737-53A1242 (Revision 2) — requires operators to follow external documents for technical detail (Requirement).","Multiple aircraft types covered (737-600, -700, -700C, -800, -900) as identified by the service bulletin — affects a broad operator base (Applicability).","Inspection required of multiple locations and components within Section 48 (sealant, flight control cables, fittings, pulleys, horizontal stabiliser jackscrew, ballnut, gimbal pins) — varied technical checks increase maintenance complexity (Background / Requirement).","Fixed compliance window of 2,500 flight cycles or 18 months — creates scheduling and tracking burdens for operators (Compliance).","Corrective work is specified by the referenced FAA AD and service bulletin rather than set out in full in the AD — operators must obtain and apply those external technical procedures (Requirement).","Legal force and an effective date (becomes effective 8 April 2008) — establishes an enforceable timeline for action (Compliance / Effective date).","Potential regulatory uncertainty from later revisions of the Boeing service bulletin that are only effective if FAA-approved — dependency on external approvals (Requirement note)."],"plain_english_summary":"This Airworthiness Directive requires operators of certain Boeing 737-600/700/700C/800/900 series aircraft (as identified in Boeing Service Bulletin 737-53A1242) to inspect Section 48 for correct sealant application and for corrosion on flight‑control components, and to carry out the technical work specified in FAA AD 2008-05-05. Compliance is mandatory within 2,500 flight cycles or 18 months; the measure responds to reports of moisture ingress into the Section 48 cavity."},"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-b737-317-section-48-cavity","history":"/api/acts/ad-b737-317-section-48-cavity/history","analysis":"/api/acts/ad-b737-317-section-48-cavity/analysis","conflicts":"/api/acts/ad-b737-317-section-48-cavity/conflicts","importantCases":"/api/acts/ad-b737-317-section-48-cavity/important-cases","documents":"/api/acts/ad-b737-317-section-48-cavity/documents"}}