{"id":"F2006B02872","name":"AD/B737/169 - Aft Pressure Bulkhead BS 1016 and Vertical Fin Forward Attachment Body Section 48","slug":"ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42214,"registerId":"commonwealth-F2006B02872-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/169 - Aft Pressure Bulkhead BS 1016 and Vertical Fin Forward Attachment Body Section 48","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n![](image.002.png)  \nBoeing 737 Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.003.png)![](image.002.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\nAD/B737/169 Aft Pressure Bulkhead BS 1016 and Vertical Fin\n\nForward Attachment Body Section 48\n\n  \n12/2001\n\nApplicability: Model 737-600, \\-700, and \\-800 aircraft, with line numbers 1 through 405, and line\n\nnumbers 466, 585, 590, and 793.\n\nRequirement: Action in accordance with the technical requirements of FAA Emergency AD 2001- 21-51.\n\nIf any damage is found during the inspection required by this Directive, before further flight, perform a detailed visual inspection of the vertical beam web installation for damage, in accordance with Boeing Telegraphic Service Bulletin 737-53A1238. If damage is found, before further flight, repair all damage per data meeting the type certification basis of the aircraft approved by a Boeing Company Designated Engineering Representative (DER), who has been authorised by the Manager, Seattle Aircraft Certification Office (ACO), to make such findings.\n\nNote: Boeing Telegraphic Service Bulletin 737-53A1238, dated 11 October 2001, refers.\n\nCompliance: As specified in the Requirement document.\n\nThis Airworthiness Directive becomes effective on 29 November 2001.\n\nBackground: The FAA received a report of an operator finding damage to the web of the aft pressure bulkhead at body station (BS) 1016 on a Model 737-700 series aircraft. During replacement of the damaged web sections of the bulkhead, additional damage to the vertical shear beam web and to the skin adjacent to the attachment fittings of the vertical fin at BS 1016 was found. A shimmy event of the main landing gear (MLG) on that aircraft was also reported, and was so severe that it damaged the MLG and resulted in replacement of the right MLG. Subsequent similar reports of damage were received from other operators.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nAD/B737/169 (Continued)\n\n![](image.004.png)Such damage at BS 1016, if not found and corrected, could result in structural failure of the aft pressure bulkhead and consequent uncontrolled decompression, or loss of structural integrity of the forward support of the vertical fin, loss of the vertical fin, and consequent loss of control of the aircraft.\n\n![Signature of Neville Probert, Delegate of the Civil Aviation Safety Authority.](image.005.png)  \n\nNeville Probert\n\nDelegate of the Civil Aviation Safety Authority 18 October 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 7 November 2001.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD adopts the FAA Emergency AD technical actions and applies them to a defined subset of 737-600/ -700/ -800 line numbers (Applicability; Requirement). The instrument narrows application to listed aircraft and does not expand the FAA's corrective scope; there is no text in the document indicating an enlargement or departure from the FAA action (Requirement/Background)."},"complexity_factors":["Cross-reference to FAA Emergency AD 2001-21-51 for technical requirements (Requirement) creates dependency on an external document.","Applicability limited to precise models and specific line numbers, requiring operators to determine if individual aircraft are in scope (Applicability).","Repairs must be per data meeting the type certification basis and approved by a Boeing DER authorised by the Seattle ACO Manager, adding an approval gate and reliance on manufacturer-designated engineering authority (Requirement).","\"Before further flight\" remediation imposes immediate grounding risk and operational disruption for affected aircraft (Requirement/Compliance).","Reference to Boeing Telegraphic Service Bulletin 737-53A1238 for inspection detail requires access to manufacturer service information (Note/Requirement).","Ambiguity in what constitutes reportable \"damage\" requires judgment in inspections and may produce inspection variance between operators (Requirement/Background)."],"plain_english_summary":"This directive requires listed Boeing 737-600/-700/-800 aircraft to follow FAA Emergency AD 2001-21-51: inspect the aft pressure bulkhead at body station 1016 and the vertical-fin forward attachment. Operators must perform detailed inspections and, if damage is found, repair per Boeing-approved data authorised by a Boeing Designated Engineering Representative before further flight (Requirement). The rule aims to prevent uncontrolled decompression or loss of the vertical fin (Background); inspection, repair and grounding costs fall to operators and compliance timing follows the FAA document."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It addresses a specific safety-critical structural defect identified in early-production Boeing 737 Next Generation aircraft. The instrument does not expand beyond its original purpose of mandating inspection and repair of the aft pressure bulkhead and vertical fin attachment area."},"complexity_factors":["Short, single-purpose directive (approximately 500 words)","Only 4 defined/model-specific applicability criteria (line numbers)","Heavy reliance on external technical documents (FAA Emergency AD 2001-21-51 and Boeing Service Bulletin 737-53A1238) — the actual technical requirements are not reproduced in the text","Simple conditional structure: if damage found → inspect further → if more damage found → repair before flight","No nested exceptions or complex cross-referencing within the instrument itself","Single compliance pathway with no alternative methods stated"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and, if needed, Boeing‑approved repairs of the aft pressure bulkhead and vertical‑fin attachment on certain early‑production Boeing 737‑600/700/800 aircraft after cracks and structural wear were found. Operators of the affected line‑numbered planes must follow FAA Emergency AD 2001‑21‑51; non‑compliant aircraft may be grounded. Effective 29 Nov 2001."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48","history":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48/history","analysis":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48/analysis","conflicts":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48/conflicts","importantCases":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48/important-cases","documents":"/api/acts/ad-b737-169-aft-pressure-bulkhead-bs-1016-and-vertical-fin-forward-attachment-body-section-48/documents"}}