{"id":"F2006B02868","name":"AD/B737/165 - Aft Pressure Bulkhead-to-Fuselage Attachment","slug":"ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42210,"registerId":"commonwealth-F2006B02868-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nBoeing 737 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B737/165 Aft Pressure Bulkhead-to-Fus","sectionType":"part","heading":"AD/B737/165 Aft Pressure Bulkhead-to-Fuselage Attachment 10/2001","content":"# AD/B737/165 Aft Pressure Bulkhead-to-Fuselage Attachment 10/2001\n\nApplicability: Model 737-700 and –800 series aircraft; line numbers 4, 6, 9 through 20, 29, and 31\n\nthrough 46.\n\nRequirement: Inspect in accordance with the technical requirements of FAA AD 2001-13-23 Amdt 39-12305.\n\nNote: Boeing Service Bulletin 737-53-1212, including Appendix A, refers.\n\nCompliance: Before the accumulation of 3,000 total flight cycles, or within 90 days after 4 October 2001, whichever occurs later.\n\nThis Airworthiness Directive becomes effective on 4 October 2001.\n\nBackground: This Directive requires inspection of certain tension bolts at the attachment of the aft pressure bulkhead to the fuselage at body station 1016 to determine if the correct parts are installed. This action is intended to prevent fatigue cracking along the bulkhead- to-fuselage attachment.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 27 August 2001\n\n![](image.001.png)","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific unsafe condition identified in particular Boeing 737 production batches regarding aft pressure bulkhead attachment bolts. There is no evidence of scope creep; the directive remains tightly focused on the original safety issue without expanding to unrelated systems or aircraft types."},"complexity_factors":["Very short document (approximately 250 words)","Only 3 substantive operative sections: Applicability, Requirement, and Compliance","Single cross-reference to FAA AD 2001-13-23 and Boeing Service Bulletin 737-53-1212","No defined terms section — technical terms are used in their ordinary aviation engineering sense","Simple temporal compliance condition ('whichever occurs later') with no nested exceptions","No conditional logic beyond the applicability criteria (specific model and line numbers)"],"plain_english_summary":"This safety order requires owners and operators of specified Boeing 737‑700/800 line numbers (and their maintenance personnel) to inspect the tension bolts where the aft pressure bulkhead attaches at body station 1016, following FAA AD 2001‑13‑23 and Boeing Service Bulletin 737‑53‑1212. Inspections must occur before 3,000 total flight cycles or within 90 days after 4 October 2001. It prevents fatigue cracking of the bulkhead joint that could cause rapid decompression or structural failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No change to scope is evident in the source text. The directive applies to specified 737‑700/‑800 line numbers and mandates inspections of aft pressure bulkhead‑to‑fuselage tension bolts in accordance with FAA AD 2001‑13‑23 and Boeing Service Bulletin 737‑53‑1212, with the compliance timing set as stated."},"complexity_factors":["Narrow applicability: specific to Model 737‑700/‑800 and listed line numbers (Applicability)","Technical inspection requirement relies on external documents: FAA AD 2001‑13‑23 and Boeing Service Bulletin 737‑53‑1212 (Requirement/Note)","Clear compliance trigger combining flight cycles and calendar time: before 3,000 total flight cycles or within 90 days after 4 Oct 2001 (Compliance)","Single technical focus (tension bolts at body station 1016) reduces breadth but requires parts identification and inspection skills (Background/Requirement)","Regulatory enforcement by CASA delegate under CAR 1998 subreg 39.1(1) introduces administrative oversight","Operators must absorb direct inspection costs and logistical scheduling to meet the deadline (Compliance/Requirement)"],"plain_english_summary":"**This Airworthiness Directive requires operators of certain Boeing 737‑700 and 737‑800 aircraft to inspect the aft pressure bulkhead‑to‑fuselage tension bolts per FAA AD 2001‑13‑23 and Boeing Service Bulletin 737‑53‑1212 to verify correct parts and prevent fatigue cracking.**\n\nOperators must complete inspections before 3,000 total flight cycles or within 90 days after 4 October 2001, whichever is later. The CASA delegate issues the requirement; operators bear the inspection costs and must follow the referenced technical instructions."},"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-b737-165-aft-pressure-bulkhead-to-fuselage-attachment","history":"/api/acts/ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment/history","analysis":"/api/acts/ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment/analysis","conflicts":"/api/acts/ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment/conflicts","importantCases":"/api/acts/ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment/important-cases","documents":"/api/acts/ad-b737-165-aft-pressure-bulkhead-to-fuselage-attachment/documents"}}