{"id":"F2006B04960","name":"AD/CESSNA 170/29 Amdt 1 - Aft Fuselage Bulkhead Assembly","slug":"ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44833,"registerId":"commonwealth-F2006B04960-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 170/29 Amdt 1 - Aft Fuselage Bulkhead Assembly","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)  Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes\n\n \n\nAD/CESSNA 170/29\n\nAmdt 1\n\n\nAft Fuselage Bulkhead Assembly 2/74\n\n \n\nApplicability: All models 172 with S/Nos. 17260759 to 17261495, F17200905 to F17201034, FR17200351 to FR17200440.\n\n \n\nRequirement: Action in accordance with Cessna SL SE73-37. Compliance:  Within 100 hours time in service after 28 February 1974.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied text contains no comparison to an earlier or original instrument, and it does not state any change in applicability or substantive scope within the document. Based solely on the supplied text, there is no basis to conclude the scope has changed from an earlier intent."},"complexity_factors":["Narrow and specific applicability defined by precise serial number ranges","Short, explicit compliance window (100 hours after 28 February 1974)","Mandates compliance with an external technical document (Cessna SL SE73-37)","No detailed procedural or enforcement provisions in the AD text itself","Technical subject-matter (airframe assembly) implies specialized work though not detailed here"],"plain_english_summary":"This AD from CASA mandates owners/operators of specified Cessna 172 serial-number ranges to perform the work described in Cessna Service Letter SE73‑37 on the aft fuselage bulkhead assembly, to be completed within 100 hours time‑in‑service after 28 February 1974. Compliance is mandatory and costs fall to operators; the AD delegates technical detail to the manufacturer’s Service Letter and does not itself state the technical steps or the safety rationale."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a straightforward amendment (Amdt 1) to an existing Airworthiness Directive. The scope remains tightly focused on the specific structural defect in the identified Cessna models. No evidence of scope creep beyond original safety purpose."},"complexity_factors":["Extremely short document (under 200 words)","Only 3 defined applicability criteria (serial number ranges)","Single, unambiguous compliance requirement referencing external technical document","No nested conditions, exceptions, or cross-references to other legislation","Clear deadline structure (100 hours time in service after fixed date)"],"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). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it does:** It requires owners and operators of specific Cessna aeroplanes to inspect and potentially fix a problem with the **aft (rear) fuselage bulkhead assembly** — that's a structural wall at the back of the passenger cabin that helps hold the plane together.\n\n**Who it affects:** Specific Cessna 172 models with serial numbers between:\n- 17260759 to 17261495\n- F17200905 to F17201034  \n- FR17200351 to FR17200440\n\n**What must be done:** Follow the instructions in **Cessna Service Letter SE73-37** (a technical bulletin from the manufacturer).\n\n**When:** Within 100 hours of flying time after 28 February 1974.\n\n**Why it matters:** Structural failures in flight can be catastrophic. This AD ensures a known weakness in the rear fuselage structure is identified and fixed before it causes an accident."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly","history":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly/history","analysis":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly/analysis","conflicts":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly/conflicts","importantCases":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly/important-cases","documents":"/api/acts/ad-cessna-170-29-amdt-1-aft-fuselage-bulkhead-assembly/documents"}}