{"id":"F2006B05225","name":"AD/CESSNA 206/20 - Wing Flap Actuator Ball Nut Assemblies","slug":"ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45493,"registerId":"commonwealth-F2006B05225-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 206/20 - Wing Flap Actuator Ball Nut Assemblies","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 206 Series Aeroplanes\n\nAD/CESSNA 206/20 Wing Flap Actuator Ball Nut Assemblies 3/77\n\nApplicability: Model U206 with S/Nos. as detailed in Cessna SL SE76-25.\n\nRequirement: 1. Inspect P/N C301002-0101 or P/N C301002-0102 wing flap actuator for date stamp code as detailed in Cessna SL SE76-25.\n\n    2. If the date stamp code on the actuator is OH, HH, WH or ZH, install a placard near the flap control which reads:\n\n“FLAP EXTENSION PROHIBITED”\n\nNote: This placard may be removed when the Paragraph 3 requirement is satisfied.\n\n    3. Replace affected wing flap actuator ball nut assemblies in accordance with Cessna SL SE76-25.\n\nCompliance: Paragraphs 1 and 2 \\- Before further flight after 28 January 1977.\n\nParagraph 3 \\- Within 100 hours time in service after 28 January 1977.","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 specific aircraft model. It has not expanded beyond its original purpose of addressing the wing flap actuator ball nut assembly issue identified in 1976-1977."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined part numbers (P/N C301002-0101 and P/N C301002-0102)","Simple conditional logic: if date stamp matches specific codes → apply placard → replace part","Single cross-reference to external document (Cessna Service Letter SE76-25 for serial numbers)","Clear, unambiguous compliance deadlines (immediate vs. 100 hours)","No nested exceptions or complex definitional sections"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for **Cessna 206 series aircraft**.\n\n**What it does:**\n- Requires owners/operators to inspect the wing flap actuator (a mechanical part that controls the wing flaps) on specific Cessna U206 model aircraft\n- Identifies certain date stamp codes (OH, HH, WH, or ZH) that indicate potentially faulty ball nut assemblies\n- If those codes are found, operators must:\n  - **Immediately** install a warning placard prohibiting flap extension (before flying again after 28 January 1977)\n  - **Within 100 flight hours**, replace the faulty ball nut assemblies entirely\n\n**Who it affects:**\n- Owners and operators of Cessna U206 aircraft with specific serial numbers listed in Cessna Service Letter SE76-25\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nWing flaps are critical for safe takeoff and landing. Faulty ball nut assemblies in the flap actuator could cause flap failure — potentially leading to loss of control during landing or takeoff. This directive forces immediate grounding (via the placard) until permanent repair, preventing accidents while allowing limited operation to reach a maintenance facility."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive sets out a targeted corrective requirement for specific actuators on specified U206 serial numbers and prescribes inspection, placarding if certain date codes are present, and replacement within a defined time. Nothing in the text indicates an expansion or narrowing of scope from what it declares; the scope is explicit (Applicability) and matched by the specified requirements and compliance timings (Requirements 1–3; Compliance)."},"complexity_factors":["Narrow applicability tied to specific model and serial numbers (Applicability)","Action sequence: inspection -> potential placard installation -> replacement (Requirements 1–3)","Identification depends on interpreter reading specific date-stamp codes (Requirement 1)","Dependency on an external document (Cessna SL SE76-25) for replacement procedure (Requirement 3)","Two-tiered compliance timing (immediate before next flight for inspection/placard; 100 service hours for replacement) (Compliance)","Operational constraint (placard prohibiting flap extension) until replacement is completed (Requirement 2; Note)"],"plain_english_summary":"Applies to Cessna 206 U206 aeroplanes (serials listed in Cessna SL SE76-25): operators must inspect wing flap actuators for date-stamp codes and, if codes OH/HH/WH/ZH are found, install a “FLAP EXTENSION PROHIBITED” placard before next flight and replace the actuator ball‑nut assemblies per Cessna SL SE76-25 within 100 flight hours.\n\nThis affects aircraft owners/operators (who pay and choose the maintenance provider), imposes an immediate operational flap restriction until fixed, and creates parts, labour and scheduling costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies","history":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies/history","analysis":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies/analysis","conflicts":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies/conflicts","importantCases":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies/important-cases","documents":"/api/acts/ad-cessna-206-20-wing-flap-actuator-ball-nut-assemblies/documents"}}