{"id":"F2006B04909","name":"AD/CESSNA 120/9 - Wing Drag Wire System","slug":"ad-cessna-120-9-wing-drag-wire-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44753,"registerId":"commonwealth-F2006B04909-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 120/9 Wing Drag Wire System 5/","sectionType":"part","heading":"AD/CESSNA 120/9 Wing Drag Wire System 5/2003","content":"# AD/CESSNA 120/9 Wing Drag Wire System 5/2003\n\nApplicability: All Model 120 and 140 aircraft.\n\nRequirement: Inspect wing drag wire system for loose or broken drag wires and inspect ribs for damage. Install inspection openings aft of the rear spar just inboard of Rib 5 and just outboard of Rib 10, if not already installed.\n\nFollowing inspection, before further flight; re-rig loose drag wires, replace broken drag wires, and repair or replace buckled drag ribs as necessary. Replace broken No. 6 drag wires in the outer wing panel with No. 8 drag wires.\n\nBuckling of the intermediate rib flanges at the spar cutouts does not render the wing unserviceable, however, reinforcement with Cessna part number 10004-58 is recommended. If the flanges are cracked, before further flight, install the above specified reinforcement.\n\nNote: FAA AD 48-25-03 and Cessna Service Letters 27 and 39 refer.\n\nCompliance: Within 100 hours time in service or 12 months after 15 May 2003, whichever occurs first. Thereafter at intervals not to exceed 100 hours time in service.\n\n![](image.002.jpeg)  \nThis Airworthiness Directive becomes effective on 15 May 2003. Background: The FAA requires regular inspection of the wing drag wire system.\n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 4 April 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 23 April 2003.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with narrow, targeted scope. It addresses a specific mechanical defect in a specific aircraft model series. There is no evidence of scope creep; the directive remains focused on its original safety purpose."},"complexity_factors":["Single, specific aircraft type (Cessna 120/140 series)","Clear, sequential instructions with minimal conditional language","Only 3 defined elements: applicability, requirement, and compliance timeframe","No cross-references to other legislation (only advisory references to FAA AD and Cessna Service Letters)","Simple temporal trigger (100 hours/12 months, then recurring 100 hours)","One minor technical exception noted (buckling without cracking does not ground aircraft, but reinforcement recommended)"],"plain_english_summary":"CASA has issued a mandatory safety order for all Cessna Model 120 and 140 aeroplanes requiring inspection and remediation of wing drag wire systems and wing ribs to prevent in‑flight structural failure.  \n\nOwners must provide inspection access and, within 100 flight hours or 12 months (and every 100 hours thereafter), inspect and tighten, replace, upgrade or reinforce wires and repair or replace damaged ribs before further flight."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety purpose of regular inspection and repair of the wing drag wire system for Cessna 120/140 aircraft. It does not materially expand scope beyond addressing that unsafe condition: it prescribes inspection intervals, specific corrective actions, and the installation of inspection openings where absent, and cross‑references FAA and manufacturer guidance. There is no substantive enlargement of regulated items or affected classes beyond the stated applicability (all Model 120 and 140 aircraft)."},"complexity_factors":["Short, self‑contained instrument (single AD)","Limited number of concrete actions (inspect, install openings, re‑rig/replace/repair, replace specific wires, install reinforcement if cracked)","One worked example of conditionality: buckling permitted vs cracking mandatory repair","Single recurring compliance interval (100 hours) with initial grace period (100 hours or 12 months after 15 May 2003)","References to external documents (FAA AD 48‑25‑03 and Cessna Service Letters 27 and 39) introduce moderate cross‑reference complexity","Specific part numbers required (No. 8 drag wires; reinforcement P/N 10004‑58)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998. It makes specific inspection and repair requirements mandatory for Cessna Model 120 and 140 aircraft.\n- It requires: (Requirement section)\n  - Inspect the wing drag wire system for loose or broken drag wires and inspect wing ribs for damage.\n  - Install inspection openings aft of the rear spar just inboard of Rib 5 and just outboard of Rib 10 if those openings are not already present.\n  - Before further flight after inspection, re‑rig any loose drag wires, replace any broken drag wires, and repair or replace buckled drag ribs as necessary.\n  - Replace any broken No. 6 drag wires in the outer wing panel with stronger No. 8 drag wires.\n  - If the intermediate rib flanges at the spar cutouts are buckled, the wing may still be used, but Cessna part number 10004‑58 reinforcement is recommended. If those flanges are cracked, the reinforcement (part 10004‑58) must be installed before further flight.\n- The AD cross‑references FAA AD 48‑25‑03 and Cessna Service Letters 27 and 39 for background and technical detail (Note).\n\n**Who must comply and who pays**\n\n- Owners and operators of all Cessna 120 and 140 aircraft must comply. Compliance is mandatory under the AD; an aircraft may not be legally flown in Australia unless the AD’s requirements are met.\n- The aircraft owner/operator pays for inspections, any structural modifications (installation of inspection openings), parts (replacement drag wires, reinforcement parts), and labour. Maintenance organisations with appropriate approvals will generally perform the work.\n\n**When and how often**\n\n- Initial compliance: within 100 hours time in service (TIS) or within 12 months after 15 May 2003, whichever comes first (Compliance section).\n- Ongoing: after the initial action, inspections are required at intervals not exceeding 100 hours TIS.\n\n**Why the rule exists (stated purpose) and how that translates to obligations**\n\n- The Background section states the FAA requires regular inspection of the wing drag wire system. The AD’s stated purpose is to correct an unsafe condition relating to loose or broken wing drag wires and damaged ribs.\n- Mechanically, that means operators must inspect at specified intervals, fix any faults before further flight, and upgrade/repair particular components (for example replace No. 6 with No. 8 drag wires in the outer wing panel and fit reinforcement where flanges are cracked).\n\n**Practical effects, incentives and trade‑offs**\n\n- Behaviour change required: regular (100‑hour) inspections and corrective maintenance become routine for affected aircraft; some aircraft will require structural access modification (cutting/installing inspection openings) if they do not already have them.\n- Direct costs: inspection labour, potential downtime while parked until repairs are done, parts cost (drag wires, reinforcement P/N 10004‑58), and possibly additional maintenance if ribs are cracked or buckled.\n- Distribution of costs and benefits: the cost burden falls on Cessna 120/140 owners/operators (a concentrated group). The safety benefits accrue to the operator, pilot, passengers and third parties (also concentrated to users) and to the regulator’s safety objectives (diffuse public interest).\n- Effects on private enterprise: maintenance providers and parts suppliers will receive repeat business; operators face a compliance cost that may be proportionally larger for privately‑owned vintage aircraft compared with commercial fleets.\n- Implementation risks and practical issues: availability of the specified parts (No. 8 wires, reinforcement P/N 10004‑58) could delay repairs; installing inspection openings is a structural alteration that requires approved procedures and competent maintenance staff; inconsistent interpretation of “buckled versus cracked” flanges could affect whether reinforcement is mandatory or only recommended.\n- Compliance burden and enforcement: the AD is mandatory. Failure to comply would render an aircraft unairworthy under CASR. The AD sets clear pass/fail triggers (broken wire, cracked flange) and a firm repetitive inspection interval (100 hours), which simplifies enforcement but creates ongoing compliance obligations.\n\n**Specific conditional rules to note**\n\n- Buckled intermediate rib flanges alone do not make the wing unserviceable; reinforcement is only recommended in that case. But if flanges are cracked, installing reinforcement part number 10004‑58 is mandatory before further flight (Requirement section).\n- Replacement of broken No. 6 drag wires in the outer wing panel with No. 8 drag wires is a mandatory corrective action (Requirement section).\n\n**Sources cited by the AD**\n\n- The AD explicitly refers users to FAA AD 48‑25‑03 and Cessna Service Letters 27 and 39 for the technical background and repair/inspection details (Note/Background).\n\n**Net mechanical effect**\n\n- Routine 100‑hour inspections of the wing drag wire system become compulsory for all Cessna 120 and 140 aircraft, with mandatory repair/parts upgrade actions where specified. Installation of inspection openings and reinforcement in certain cracked cases are required. The AD turns a recommended safety practice (regular inspection) into an enforceable legal obligation with recurring intervals and specified corrective steps.\n\n(Referenced sections: Applicability; Requirement; Compliance; Note; Background.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-120-9-wing-drag-wire-system","history":"/api/acts/ad-cessna-120-9-wing-drag-wire-system/history","analysis":"/api/acts/ad-cessna-120-9-wing-drag-wire-system/analysis","conflicts":"/api/acts/ad-cessna-120-9-wing-drag-wire-system/conflicts","importantCases":"/api/acts/ad-cessna-120-9-wing-drag-wire-system/important-cases","documents":"/api/acts/ad-cessna-120-9-wing-drag-wire-system/documents"}}