{"id":"F2006B02685","name":"AD/B727/162 - Vertical Beam Web and Forward Flange of the Aft Pressure Bulkhead","slug":"ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42001,"registerId":"commonwealth-F2006B02685-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/162 - Vertical Beam Web and Forward Flange of the Aft Pressure Bulkhead","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Boeing 727 Series Aeroplanes\n\n \n\n# AD/B727/162 Vertical Beam Web and Forward Flange\n\nof the Aft Pressure Bulkhead\n\nApplicability: All Model 727 aircraft.\n\n# 13/99\n\n \n\nRequirement: Action in accordance with the technical requirements of FAA AD 99-18-05 Amdt 39- 11271.\n\n \n\nNote: Boeing Service Bulletins 727-53-0210 and 727-53-0055 refer.\n\n \n\nCompliance: As specified in the Requirement document for the initial and repetitive inspections, with a revised effective date of 30 December 1999.\n\n \n\nThis Airworthiness Directive becomes effective on 30 December 1999.\n\n \n\nBackground: The FAA received reports of fatigue cracks in the vertical beam web and forward flange of the aft pressure bulkhead. Such fatigue cracking could result in the inability of subject vertical beam to withstand the fail-safe loads, and consequent loss of cabin pressurisation.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused, narrow scope addressing a specific structural fatigue issue on a specific aircraft type. The scope remains tightly constrained to the identified safety risk without expansion into broader operational or maintenance requirements."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined elements: 'Applicability' and 'Requirement' with clear scope","Single cross-reference to external FAA document (AD 99-18-05) — no internal cross-referencing","No conditional logic or nested exceptions","Straightforward compliance structure with single effective date","Technical content is incorporated by reference rather than included in text"],"plain_english_summary":"This CASA Airworthiness Directive orders Australian owners, operators and maintainers of Boeing 727s to inspect and maintain the vertical beam web and forward flange of the aft pressure bulkhead, following the FAA’s AD 99-18-05 and Boeing service bulletins. It responds to discovered fatigue cracking that could lead to structural failure and sudden cabin depressurisation, and requires inspections and repairs per the FAA schedule (effective 30 December 1999)."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The directive maintains its original scope: mandating inspections and corrective action for the vertical beam web and forward flange of the aft pressure bulkhead on all Model 727 aircraft. The instrument adopts FAA AD 99-18-05 and references Boeing service bulletins; the only explicit procedural change in this text is a revised effective date of 30 December 1999."},"complexity_factors":["Cross-references external FAA AD 99-18-05 (Amdt 39-11271) rather than setting standalone technical detail, requiring operators to consult another regulatory instrument.","Refers to multiple Boeing service bulletins (727-53-0210 and 727-53-0055) for technical procedures, adding document-management burden.","Safety-critical inspections of structural parts (vertical beam web and forward flange of aft pressure bulkhead) require specialist maintenance skills and possible repair actions.","Compliance requires initial and repetitive inspection scheduling and record-keeping, increasing operational planning complexity.","Applicability to all Model 727 aircraft creates wide coverage and potentially disparate fleet conditions to assess.","Effective-date revision creates a compliance-timing constraint (effective 30 December 1999) that operators must track."],"plain_english_summary":"Requires all Model 727 operators to carry out the initial and repetitive inspections and any corrective actions set out in FAA AD 99‑18‑05 (Amdt 39‑11271) and the Boeing service bulletins referenced. The rule targets fatigue cracking in the vertical beam web and forward flange of the aft pressure bulkhead because such cracking can stop the beam from carrying fail‑safe loads and cause loss of cabin pressurisation; operators are responsible for inspections and repairs and must comply by 30 December 1999."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead","history":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead/history","analysis":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead/analysis","conflicts":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead/conflicts","importantCases":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead/important-cases","documents":"/api/acts/ad-b727-162-vertical-beam-web-and-forward-flange-of-the-aft-pressure-bulkhead/documents"}}