{"id":"F2006B05127","name":"AD/CESSNA 185/36 - Aileron Balance Weight Installation","slug":"ad-cessna-185-36-aileron-balance-weight-installation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45163,"registerId":"commonwealth-F2006B05127-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 185/36 - Aileron Balance Weight Installation","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nCessna 185 Series Aeroplanes\n\nAD/CESSNA 185/36 Aileron Balance Weight Installation 1/84\n\nApplicability: All models 185, 185A thru 185E, A185E and A185F aircraft modified in accordance with Robertson STC SA 1441WE.\n\nRequirement: 1. Determine if the aircraft has been modified in accordance with the applicable STC at Robertson Aircraft Corporation Repair Station No 415-23 prior to 1 August 1983, and if so proceed with the inspection requirement.\n\n    2. Measure the height of all aileron balance weights. If the measured height of all weights is approximately 3/4 inch, the weights are correctly installed and no further action is necessary.\n\n    3. Any weight with a measured height of approximately 1/2 inch, requires replacement before further flight with balance weights of the appropriate part number in accordance with the applicable STC data or Robertson S.B. No. 20. Rebalance the ailerons within the limits specified by the Cessna Aircraft Company Service Manual for the aircraft involved.\n\nCompliance: Within 50 hours time in service after 31 January 1983.\n\nBackground: Failure to comply with the intent of this Directive could result in destructive aileron flutter.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a limited population of modified aircraft. It has not expanded beyond its original purpose of preventing aileron flutter in Robertson-modified Cessna 185s."},"complexity_factors":["Single, narrow applicability (one aircraft series, one specific modification)","Straightforward conditional logic (if-then measurement with only two outcomes)","Minimal cross-referencing (only references external STC data and Cessna manual for rebalancing procedure)","No defined terms section — uses common aviation terminology","Single compliance deadline with clear trigger (50 hours after fixed date)","Background provides clear safety rationale"],"plain_english_summary":"Owners/operators of certain Cessna 185-series aeroplanes modified with the Robertson STC (installed before 1 Aug 1983) must inspect aileron balance weights and replace undersized (~1/2\" tall) weights before the next flight; ~3/4\" is acceptable. Compliance was required within 50 flight hours after 31 Jan 1983.\n\nThe AD prevents aileron flutter from incorrect balance weights, which can cause catastrophic structural failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No change of scope from the instrument's stated purpose: the AD sets a narrowly targeted inspection and corrective requirement for Cessna 185-series aeroplanes modified under the named STC at Robertson Repair Station No. 415-23, with a 50‑hour compliance window to mitigate aileron flutter (Applicability; Requirements; Compliance; Background)."},"complexity_factors":["Targeted applicability to specific models and a specific STC performed at a named repair station before a set date — requires historical maintenance verification (Applicability; Requirement 1).","Identification burden: operators must determine whether the aircraft was modified at Robertson Repair Station No. 415-23 prior to 1 August 1983, which may require tracing records (Requirement 1).","Measurement ambiguity: pass/fail thresholds use approximate heights (≈3/4 inch vs ≈1/2 inch), which can create borderline determinations and require judgment or tooling (Requirement 2).","Corrective action depends on external documents: replacement must follow the applicable STC data or Robertson S.B. No. 20, and rebalancing must meet Cessna Service Manual limits — multiple reference documents add procedural complexity (Requirement 3).","Compliance timing is short and prescriptive: work must be done within 50 hours time in service after 31 January 1983, imposing scheduling and operational constraints on owners/operators (Compliance).","Safety consequence is explicit (risk of destructive aileron flutter) which supports strict compliance but places full compliance cost and operational responsibility on the aircraft owner/operator (Background; Requirement 3)."],"plain_english_summary":"Mandates that owners/operators of Cessna 185-series aeroplanes modified under `Robertson STC SA 1441WE` (where the modification was done at Robertson Repair Station No. 415‑23 before 1 August 1983) inspect aileron balance weights, measure their height, and replace any weight measuring about 1/2 inch with the correct part and rebalance the ailerons. Work must be completed within 50 hours' time in service after 31 January 1983. The directive is issued to address the risk of destructive aileron flutter."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation","history":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation/history","analysis":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation/analysis","conflicts":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation/conflicts","importantCases":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation/important-cases","documents":"/api/acts/ad-cessna-185-36-aileron-balance-weight-installation/documents"}}