{"id":"F2006B03246","name":"AD/B747/66 Amdt 2 - Lower Lobe Cargo Door Locking System","slug":"ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42670,"registerId":"commonwealth-F2006B03246-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/66 Amdt 2 - Lower Lobe Cargo Door Locking System","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)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/66\n\nAmdt 2\n\n  \nLower Lobe Cargo Door Locking System 3/91\n\nApplicability: Model 747 series line number 001 and subsequent.\n\nRequirement: Unless already accomplished; action in accordance with the technical requirements of FAA AD 90-09-06 Amdt 39-6581.\n\nNote: Boeing SB’s 747-52A2206 and 747-52A2209 refer.\n\nCompliance: As specified in the Requirement Document.\n\nBackground: A lower lobe forward cargo door partially opened in flight due to damaged lock sectors. Amendment 1 was raised in response to the FAA decision, following a second occurrence, to accelerate the compliance time previously required by AD 88- 12-04, and for installation of certain modifications as well as additional inspections and tests in the interim.\n\nThis amendment is raised to reflect an additional requirement of FAA Amdt 39-6581, AD 90-09-02; which supersedes Amdt 39-6166, AD 89-05-54.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: preventing cargo door failures on Boeing 747 aircraft. Amendment 2 simply updates the Australian directive to match a revised American FAA directive (superseding earlier amendments), without expanding to other aircraft types, other door systems, or unrelated safety issues."},"complexity_factors":["Single, specific technical requirement (follow the FAA directive)","Only 1 defined term implicitly used ('line number' referring to manufacturing sequence)","No nested conditional logic — straightforward applicability rule (all 747s from line 001 onwards)","Minimal cross-referencing (only to external FAA AD and Boeing Service Bulletins)","Short document (approximately 150 words of substantive text)","Clear compliance pathway specified (follow the Requirement Document)"],"plain_english_summary":"This is a **safety directive for Boeing 747 aircraft** that mandates specific maintenance actions to prevent cargo doors from opening mid-flight.\n\n**What it does:**\n- Requires airlines and aircraft operators to inspect and modify the **lower lobe (bottom section) cargo door locking system** on all Boeing 747 planes starting from the very first one built (line number 001 onwards)\n- Operators must follow the technical instructions set out in an American aviation safety directive (FAA AD 90-09-06)\n\n**Why it matters:**\n- A cargo door partially opened during flight because locking components (called \"lock sectors\") were damaged\n- This created a serious safety risk — rapid decompression or structural damage could occur if a door opens at altitude\n- The directive was strengthened after a **second incident** occurred, prompting faster compliance deadlines and extra inspections\n\n**Who must comply:**\n- Anyone operating Boeing 747 aircraft in Australia\n- Maintenance organisations servicing these aircraft\n\n**Key documents referenced:**\n- Boeing Service Bulletins 747-52A2206 and 747-52A2209 (technical instructions from the manufacturer)\n- FAA Airworthiness Directive 90-09-06 (the US safety rule this Australian directive adopts)"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment expands the Australian AD's obligations to reflect an additional FAA requirement (FAA Amdt 39-6581, AD 90-09-02) that supersedes an earlier FAA AD. The instrument therefore increases or updates the mandated actions for the applicable Boeing 747 fleet by incorporating the later FAA directive and its associated requirements (Background; Requirement)."},"complexity_factors":["Direct cross-reference to an external FAA AD (FAA AD 90-09-06 Amdt 39-6581) rather than restating technical requirements (Requirement)","Reliance on manufacturer service bulletins for technical detail (Boeing SB 747-52A2206 and 747-52A2209) (Note)","Applicability limited to a defined subset of aircraft (Model 747 series line number 001 and subsequent) which narrows but precisely defines scope (Applicability)","Several prior amendments and supersessions referenced, creating a short chain of historical ADs to track (Background)","Operational effects (modifications, inspections, tests) are described at high level but technical and scheduling specifics are deferred to the referenced documents (Requirement; Compliance)"],"plain_english_summary":"This AD makes compliance with a specific FAA airworthiness directive (FAA AD 90-09-06/Amdt 39-6581) mandatory for Boeing 747 aeroplanes line number 001 and subsequent, requiring operators and maintenance organisations to carry out the referenced Boeing service bulletin work and inspections. It responds to incidents of lower-lobe forward cargo door lock damage to prevent in‑flight openings, and will impose maintenance, parts and downtime costs on affected operators to meet the FAA-mandated fixes."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system","history":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system/history","analysis":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system/analysis","conflicts":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system/conflicts","importantCases":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system/important-cases","documents":"/api/acts/ad-b747-66-amdt-2-lower-lobe-cargo-door-locking-system/documents"}}