{"id":"F2006B02970","name":"AD/B737/7 - Fuselage Frames Adjacent to Forward Airstair","slug":"ad-b737-7-fuselage-frames-adjacent-to-forward-airstair","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42312,"registerId":"commonwealth-F2006B02970-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/7 - Fuselage Frames Adjacent to Forward Airstair","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 737 Series Aeroplanes\n\n \n\nAD/B737/7 Fuselage Frames Adjacent to Forward Airstair 8/85\n\nApplicability: All model 737 aircraft, Line Numbers 1 to 880.\n\n \n\nRequirement: 1. FAA AD 85-01-06, Amendment 39-4982, up to and including Section F, but excluding Section E.\n\n \n\n2. Boeing SB 737-53A1064, Revision 3. Compliance: As detailed in Requirement Document No 1.\n\nBackground: There have been numerous reports of cracking in the fuselage frames adjacent to the forward airstair doorway cut-out. Cracking of the frames and door cut-out internal doubler could result in a sudden loss of cabin pressure, and possibly blowout of the airstair door.\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":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"This AD adopts the FAA Airworthiness Directive 85-01-06 but modifies its scope by expressly excluding Section E while adopting up to and including Section F (Requirement 1). It also specifically mandates Boeing Service Bulletin 737-53A1064 Revision 3 as the manufacturer action (Requirement 2). Compared with a verbatim adoption of the FAA AD, this AD narrows the adopted FAA requirements (the exclusion of Section E) and adds a direct reference to a particular revision of the Boeing service bulletin, so the operative scope differs from an unmodified adoption of the FAA instrument."},"complexity_factors":["Cross-reference to external FAA AD (85-01-06) with partial adoption (up to Section F but excluding Section E) — requires reading and applying another instrument in part (Requirement 1).","Mandate to follow a manufacturer service bulletin (Boeing SB 737-53A1064 Revision 3) rather than embedding procedures — technical dependence on a separate, potentially lengthy document (Requirement 2).","Technical subject matter: structural inspections and repairs of fuselage frames and internal doubler at a door cut-out are specialist tasks requiring maintenance engineering skills.","Applicability limited to a specific fleet subset (Line Numbers 1–880) — requires accurate fleet record checks and possible trace/ownership queries (Applicability).","Safety-critical consequences (risk of sudden decompression or door blowout) increase procedural conservatism and verification demands (Background).","The exclusion of a single section (Section E) from the FAA AD creates a non-uniform adoption that increases interpretive complexity.","Compliance likely involves logistical coordination (access to door cut-out area, removal of structures, shop or field repairs), increasing operational disruption risk.","Enforcement depends on demonstrating conformance to referenced documents, which may require additional records and proof of correct application."],"plain_english_summary":"This AD requires owners/operators of early Boeing 737s (Line Nos. 1–880) to inspect—and repair if needed—the fuselage frames adjacent to the forward airstair door, by following FAA AD 85‑01‑06 (excluding Section E) and Boeing Service Bulletin 737‑53A1064 Rev. 3. It responds to reported cracking that can risk sudden cabin depressurisation or airstair blowout. Operators bear inspection/repair costs and must obtain and apply the referenced documents to comply."},"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 at the forward airstair. It has not expanded beyond its original technical purpose."},"complexity_factors":["Very short document (under 300 words)","Only 2 substantive requirements, both incorporated by reference to external documents","Simple applicability test (Line Numbers 1-880)","No defined terms section","No nested conditional logic or exceptions within the text itself","Complexity is externalised — the actual technical work is in the referenced FAA AD and Boeing Service Bulletin, not in this instrument"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific repairs or inspections on certain aircraft.\n\n**What it does:** It orders operators of early-model Boeing 737 aircraft (specifically those built as Line Numbers 1 through 880) to inspect and fix a known structural problem. The problem is **cracking in the metal frames around the forward airstair door** (the built-in staircase at the front of the plane).\n\n**Why it matters:** Cracks in these frames aren't just maintenance headaches — they can cause:\n- **Sudden loss of cabin pressure** (decompression), which is dangerous for passengers and crew\n- **Possible blowout of the airstair door** in flight, which could be catastrophic\n\n**What must be done:** Aircraft operators must follow:\n- A specific **FAA Airworthiness Directive** (85-01-06, Amendment 39-4982) — but only Sections A through F, *excluding* Section E\n- **Boeing Service Bulletin 737-53A1064, Revision 3** — the manufacturer's official repair instructions\n\n**When:** Compliance timing follows the schedule set out in that FAA directive.\n\n**Who it affects:** Airlines and operators flying early Boeing 737s (roughly the first 880 aircraft built), plus the maintenance crews who work on them."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair","history":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair/history","analysis":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair/analysis","conflicts":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair/conflicts","importantCases":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair/important-cases","documents":"/api/acts/ad-b737-7-fuselage-frames-adjacent-to-forward-airstair/documents"}}