{"id":"F2006B04905","name":"AD/CESSNA 120/5 - Fuselage Rear Bulkhead","slug":"ad-cessna-120-5-fuselage-rear-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44749,"registerId":"commonwealth-F2006B04905-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nCessna 120 and 140 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CESSNA 120/5 Fuselage Rear Bulkhead 5","sectionType":"part","heading":"AD/CESSNA 120/5 Fuselage Rear Bulkhead 5/2003","content":"# AD/CESSNA 120/5 Fuselage Rear Bulkhead 5/2003\n\nApplicability: Model 120 and 140 aircraft, with serial numbers up to and including 14289.\n\nRequirement: Inspect the lower right hand corner of the cut-out in the fuselage rear bulkhead for cracks, which usually extend down to the rivet holes at the nearest anchor nut.\n\nIf cracks are found, before further flight, install the new type bulkhead with reinforcement channel added in accordance with Cessna Drawing No. 0412169.\n\nNote: FAA AD 47-50-02 and Cessna Service Letter No. 46 refer.\n\nCompliance: Within 100 hours time in service or 12 months after 15 May 2003, whichever occurs first, and thereafter at intervals not to exceed 100 hours time in service; until the fuselage rear bulkhead (tail post) has been reinforced.\n\nThis Airworthiness Directive becomes effective on 15 May 2003.\n\nBackground: The FAA requires inspection of the fuselage rear bulkhead until modified.\n\n![](image.002.jpeg)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 4 April 2003\n\n![](image.001.png)","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted airworthiness directive addressing a specific structural defect in specific aircraft models. The scope remains precisely limited to the identified safety issue (fuselage rear bulkhead cracks) and has not expanded beyond this original technical purpose."},"complexity_factors":["Single, clearly defined applicability (two specific aircraft models with serial number cutoff)","One primary requirement with a single conditional branch (if cracks found → mandatory repair)","Straightforward compliance timeline (100 hours/12 months, then recurring 100 hours)","Only one cross-reference to external technical document (Cessna Drawing No. 0412169)","No defined terms section, no nested exceptions, no complex conditional logic","Total length: approximately 250 words"],"plain_english_summary":"Owners/operators of Cessna 120 and 140 aeroplanes (serials up to 14289) must inspect the lower‑right corner of the rear bulkhead cut‑out for cracking and, if cracks are found, ground the aircraft until a reinforced replacement bulkhead is fitted per Cessna drawing No. 0412169.\n\nInitial inspection is within 100 flight hours or 12 months of 15 May 2003, then every 100 flight hours until the new bulkhead is installed. The order responds to an FAA‑identified structural safety risk."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies exactly to the aircraft population and measures described: inspections of the rear bulkhead on Cessna 120/140 aircraft up to serial 14289, recurring until the new reinforced bulkhead per Cessna drawing is installed. It mirrors the FAA requirement noted in the background and does not broaden the affected fleet or extend obligations beyond the stated inspection/replacement regime."},"complexity_factors":["Targeted applicability limited to Cessna 120/140 with serial numbers ≤14289 (clear scope but requires serial verification).","Single, clearly identified inspection location (lower right corner of fuselage rear bulkhead cut-out) reduces diagnostic ambiguity.","Remedy requires installation to a specific manufacturer drawing (Cessna Drawing No. 0412169), creating dependence on drawing availability and technical maintenance capability.","Recurring compliance interval (100 hours or 12 months, then every 100 hours) imposes ongoing inspection burden on operators until modification.","References external documents (FAA AD 47-50-02 and Cessna Service Letter No. 46) which operators may need to consult for background or technique.","Compliance deadline tied to an effective date (15 May 2003) and enforced by CASA, creating administrative and record-keeping obligations."],"plain_english_summary":"Requires owners/operators of Cessna 120 and 140 aeroplanes (serial numbers up to and including 14289) to inspect the lower right corner of the fuselage rear bulkhead cut‑out for cracks and, if cracks are found, to install a new-type bulkhead with a reinforcement channel per Cessna Drawing No. 0412169. Inspections must occur within 100 flight hours or 12 months after 15 May 2003, then every 100 hours until the bulkhead is reinforced; owners/operators bear inspection and replacement costs and must comply with CASA’s directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead","history":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead/history","analysis":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead/analysis","conflicts":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead/conflicts","importantCases":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead/important-cases","documents":"/api/acts/ad-cessna-120-5-fuselage-rear-bulkhead/documents"}}