{"id":"F2006B03273","name":"AD/B747/95 - Wing Leading Edge Duct","slug":"ad-b747-95-wing-leading-edge-duct","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42698,"registerId":"commonwealth-F2006B03273-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/95 - Wing Leading Edge Duct","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/B747/95 Wing Leading Edge Duct 6/91\n\nApplicability: Model 747 series, line positions 2 through 707; except model 747-400 series. Requirement: Action in accordance with the Technical Requirements of FAA AD 91-06-08 Amdt\n\n39-6928.\n\nCompliance: As specified in the Requirement document with a revised effective date of 13 June 1991 for Australian registered aircraft.\n\nBackground: This Directive is raised to reflect the above FAA AD amendment which is prompted, in part, by the discovery that the existing AD (88-17-07), incorrectly states that the stress relieving procedure constitutes terminating action for titanium T-ducts.\n\nAdditionally, the FAA has determined that, in the interest of continuing airworthiness, the terminating action must be mandatory and that a proof pressure test must be required. Cracked or ruptured ducts, if not corrected, could lead to damage to wing leading edge panels and associated problems. Effective date required by the FAA is extended by two months.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific technical defect in specific Boeing 747 models. It does not expand beyond the original safety purpose of ensuring wing leading edge duct integrity."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined term implicitly referenced (line positions)","Single cross-reference to FAA AD 91-06-08 Amdt 39-6928","No nested conditional logic or exceptions — straightforward applicability statement with one exclusion (747-400 series)","Clear compliance date specified","Technical content is incorporated by reference rather than spelled out in the text itself"],"plain_english_summary":"This CASA Airworthiness Directive mandates that Australian-registered, early-production Boeing 747s (line positions 2–707; excludes 747‑400) follow the FAA’s technical fix for cracked titanium T‑ducts in wing leading edges — but corrects the original to require a proof pressure test, not just stress‑relieving, to verify the repair. It matters because failing ducts can damage leading‑edge panels and threaten structural safety."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment changes the prior scope by removing reliance on a stress‑relieving procedure as terminating action and instead making a specified terminating action mandatory and adding a proof pressure test. CASA adopts the FAA amendment for Australian‑registered aircraft with a revised effective date (13 June 1991). Operators (aircraft owners/operators) are responsible for carrying out and funding inspections, tests and repairs; the FAA issued the technical mandate and CASA adopted it for domestic compliance."},"complexity_factors":["Cross-reference to external FAA AD (91‑06‑08 Amdt 39‑6928) — requires operators to follow another regulator's technical requirements","Technical content: distinguishes between stress‑relieving procedure and a mandatory terminating repair for titanium T‑ducts","Adds a required proof pressure test (additional inspection/test step beyond previous AD)","Narrow applicability (specific Boeing 747 line positions; excludes 747‑400) but affects multiple operators","Amendment corrects an earlier incorrect statement in AD 88‑17‑07, creating a compliance change rather than a new design requirement","Compliance timing: revised effective date for Australian registered aircraft and an FAA‑driven effective date extension"],"plain_english_summary":"This directive requires operators of Boeing 747 series aeroplanes (line positions 2–707, excluding the 747‑400) to follow FAA AD 91‑06‑08 (amendment 39‑6928) as adopted by CASA, making the terminating repair for titanium wing leading‑edge T‑ducts mandatory and adding a required proof‑pressure test. CASA sets the Australian effective date at 13 June 1991. Aircraft operators bear the cost of inspections, tests and repairs; regulators (FAA, adopted by CASA) set the required actions and operators must carry them out to remain airworthy."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-95-wing-leading-edge-duct","history":"/api/acts/ad-b747-95-wing-leading-edge-duct/history","analysis":"/api/acts/ad-b747-95-wing-leading-edge-duct/analysis","conflicts":"/api/acts/ad-b747-95-wing-leading-edge-duct/conflicts","importantCases":"/api/acts/ad-b747-95-wing-leading-edge-duct/important-cases","documents":"/api/acts/ad-b747-95-wing-leading-edge-duct/documents"}}