{"id":"F2012L01160","name":"AD/B737/270 Amdt 1 - Aft Pressure Bulkhead Web - 2","slug":"ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":163143,"registerId":"commonwealth-F2012L01160-current","compilationNumber":null,"startDate":"2026-04-04","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/B737/270 Amdt 1 | Aft Pressure Bulkhead Web - 2 | 12/2012 |\n| ------------------ | ----------------------------- | ------- |\n\n| Applicability: | All Model 737-600, -700, -700C, -800, and -900 series aircraft.                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2005-21-06 Amdt 39-14344.Note: Boeing Service Bulletin 737-53A1248 original issue, or later FAA approved revision refers.The inspections required by paragraph (f) of referenced FAA AD 2005-21-06 are not required for production line number 1756 and subsequent line numbers. Refer FAA AMOC letter 120S-05-566 dated Nov 18, 2005. |\n| Compliance:    | As specified in the requirement document.                                                                                                                                                                                                                                                                                                                                                             |\n|                | This Amendment becomes effective on 8 June 2012.                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | The FAA received reports of fatigue cracks in the aft pressure bulkhead web. The actions specified by this Directive are intended to detect and correct such fatigue cracks, which could result in a rapid decompression of the aircraft.                                                                                                                                                             |\n|                | Boeing production changes have resulted in a thicker gauge web material for the rear pressure bulkhead web, with the result that the inspections required by paragraph (f) of FAA AD 2005-21-06 are no longer required for production line number 1756 and subsequent line numbers.                                                                                                                   |\n|                | The original issue of this Airworthiness Directive became effective on19 January 2006.                                                                                                                                                                                                                                                                                                                |\n\n![](image.001.png)  \nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n4 June 2012","sortOrder":0},{"sectionNumber":"AD/B737/270 Amdt 1","sectionType":"part","heading":"AD/B737/270 Amdt 1","content":"## AD/B737/270 Amdt 1","sortOrder":1},{"sectionNumber":"Aft Pressure Bulkhead Web - 2","sectionType":"part","heading":"Aft Pressure Bulkhead Web - 2","content":"## Aft Pressure Bulkhead Web - 2","sortOrder":2},{"sectionNumber":"12/2012","sectionType":"part","heading":"12/2012","content":"## 12/2012","sortOrder":3}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the Airworthiness Directive. It adds a targeted exemption for newer aircraft based on improved manufacturing, which is a standard refinement rather than scope expansion. The core purpose — ensuring structural integrity of the aft pressure bulkhead — remains unchanged."},"complexity_factors":["Short, single-purpose instrument (approximately 250 words)","Only 2 defined applicability criteria (aircraft models and production line numbers)","Single cross-reference to FAA AD 2005-21-06 Amdt 39-14344","One conditional exemption (production line 1756+)","No nested exceptions or recursive definitions","Technical aviation terminology requires domain knowledge but is standard for the field"],"plain_english_summary":"This AD mandates inspections of the aft pressure bulkhead on certain Boeing 737-600/-700/-700C/-800/-900 series airplanes to detect fatigue cracks that could cause rapid cabin decompression. It affects operators of those models, though airplanes built from production line number 1756 onward are exempt from some inspections because Boeing began using a thicker, approved material. The rule targets older builds to prevent decompression risks while recognizing newer airframes need less scrutiny."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment narrows the inspection scope for later-production aircraft: paragraph (f) inspections required by FAA AD 2005-21-06 are not required for Boeing production line number 1756 and subsequent line numbers because Boeing introduced a thicker gauge rear pressure bulkhead web (Requirement; Background). The amendment thus removes a specific inspection obligation for that subset of aircraft."},"complexity_factors":["Cross-reference to external FAA AD 2005-21-06 and Boeing Service Bulletin 737-53A1248 (requires reading multiple documents)","An exemption for production line numbers 1756 and later (distinguishing by serial/line number increases compliance tracking burden)","Reference to FAA AMOC letter 120S-05-566 for the exemption (requires review of an additional approval document)","Limited technical subject-matter (fatigue inspection/repair) but no novel regulatory mechanism or discretionary carve-outs by CASA"],"plain_english_summary":"This directive requires operators of Boeing 737‑600/700/700C/800/900 series to carry out inspections and corrective actions on the aft pressure‑bulkhead web in accordance with FAA AD 2005‑21‑06 and Boeing Service Bulletin 737‑53A1248 (Requirement). It targets fatigue cracks that could lead to rapid decompression (Background).\n\nOperators pay for inspections and any repairs and must follow the FAA‑referenced procedures; CASA enforces compliance from 8 June 2012. Aircraft with production line number 1756 and later are exempt from paragraph (f) inspections because Boeing changed to a thicker web (Requirement/Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2","history":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2/history","analysis":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2/analysis","conflicts":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2/conflicts","importantCases":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2/important-cases","documents":"/api/acts/ad-b737-270-amdt-1-aft-pressure-bulkhead-web-2/documents"}}