{"id":"F2006B03271","name":"AD/B747/93 - Section 42 Fuselage Frame Web","slug":"ad-b747-93-section-42-fuselage-frame-web","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42695,"registerId":"commonwealth-F2006B03271-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/93 - Section 42 Fuselage Frame Web","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Boeing 747 Series Aeroplanes\n\n \n\nAD/B747/93 Section 42 Fuselage Frame Web 6/91\n\nApplicability: Model 747 series with line numbers 001 through 045.\n\n \n\nRequirement: Action in accordance with the technical requirements of FAA AD 91-06-03 Amdt 39- 6923.\n\n \n\nCompliance: As specified in the Requirement Document with a revised effective date of 13 June 1991 for Australian registered aircraft.\n\n \n\nBackground: The FAA has received reports of multiple cracks in the Section 42 frames. This condition, if not corrected, could result in rapid depressurisation of the aircraft.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive focused specifically on fuselage frame cracking in early Boeing 747s. It has not expanded beyond its original purpose of addressing this specific airworthiness concern."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 operative sections: Applicability, Requirement, Compliance, and Background","No defined terms section — relies entirely on external FAA document for technical specifications","Single, clear applicability criterion (line numbers 001–045)","No nested conditions, exceptions, or cross-references to other Australian legislation","Incorporates by reference only one external document (FAA AD 91-06-03)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Boeing 747 aircraft.\n\n**What it does:**\n- Requires owners/operators of early-model Boeing 747s (serial numbers 001 through 045) to inspect and fix a structural problem in the fuselage (the main body of the aircraft).\n- The problem is cracks in \"Section 42 frames\" — these are metal supports in the aircraft's body that help maintain cabin pressure at high altitude.\n\n**Why it matters:**\n- Cracks in these frames could cause **rapid depressurisation** — meaning the cabin could suddenly lose pressure, which is extremely dangerous for everyone on board.\n- The directive makes compliance **legally mandatory** for Australian-registered aircraft. You cannot legally fly these specific planes without doing the required work.\n\n**Who it affects:**\n- Airlines or operators flying the very first Boeing 747s ever built (line numbers 1–45, produced in the late 1960s/early 1970s).\n- These aircraft must follow the technical instructions from the US Federal Aviation Administration (FAA) document AD 91-06-03, but with an Australian compliance deadline of **13 June 1991**.\n\n**In short:** If you own one of the oldest 747s in Australia, you must get these frame cracks checked and fixed by mid-1991 or ground the aircraft."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument adopts the technical requirements of FAA AD 91-06-03 for Boeing 747s with line numbers 001–045 and sets an Australian effective date (13 June 1991). The text does not expand or narrow the FAA directive's technical scope in this instrument; the only explicit adjustment is the revised effective date for Australian-registered aircraft. (Requirement; Compliance; Applicability)"},"complexity_factors":["Cross-reference to an external technical document (FAA AD 91-06-03) rather than containing technical detail in the text","Narrow applicability limited to specific aircraft line numbers (001–045), requiring operator identification","Regulatory dependency: Australian effect achieved by adopting a foreign regulator's AD and setting an Australian effective date","Potential operational complexity for implementers (inspection/repair logistics, parts, downtime) though not described here","Low legislative text length and few provisions reduce statutory complexity"],"plain_english_summary":"This instrument requires owners/operators of Australian‑registered Boeing 747s (line numbers 001–045) to carry out the inspections and corrective actions set out in FAA AD 91‑06‑03 Amdt 39‑6923, adopted with an Australian effective date of 13 June 1991. It responds to FAA reports of cracks in Section 42 fuselage frames that could cause rapid depressurisation; compliance costs and disruption fall to the aircraft owners/operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-93-section-42-fuselage-frame-web","history":"/api/acts/ad-b747-93-section-42-fuselage-frame-web/history","analysis":"/api/acts/ad-b747-93-section-42-fuselage-frame-web/analysis","conflicts":"/api/acts/ad-b747-93-section-42-fuselage-frame-web/conflicts","importantCases":"/api/acts/ad-b747-93-section-42-fuselage-frame-web/important-cases","documents":"/api/acts/ad-b747-93-section-42-fuselage-frame-web/documents"}}