{"id":"F2006B08131","name":"AD/CESSNA 303/4 Amdt 2 - Prohibition of Flight in Known Icing Conditions","slug":"ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115265,"registerId":"commonwealth-F2006B08131-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 303/4 Amdt 2 - Prohibition of Flight in Known Icing Conditions","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 T303 Series Aeroplanes\n\nAD/CESSNA 303/4\n\nAmdt 2\n\n  \n\nProhibition of Flight in Known Icing Conditions\n\n  \n10/87\n\nApplicability: Cessna model T303 aeroplanes (all serial numbers).\n\nRequirement: 1. For aircraft not modified with the installation of Cessna Modification as detailed in 2 below;\n\n    (a) Fabricate and install on the instrument panel in clear view of the pilot the following placard using letters of a minimum of 2.5mm in height:\n\n“FLIGHT INTO KNOWN ICING PROHIBITED”.\n\n    (b) Cover the airplane operating placard statement, “This airplane is approved for flight into icing conditions if the proper optional equipment is installed and operational” with opaque tape.\n\n2. For aircraft fitted with Cessna Horizontal/Vertical Stabilizer Kit SK 303-39 or SK 303-39A in accordance with Cessna Service Bulletin MEB 86-18.\n\nRemove any placard fitted in accordance with any issue of this Directive.\n\nNote: Appropriate Flight Manual amendment will be required for aircraft in either category.\n\nCompliance: Before further flight after 20 February 1986.\n\nBackground: A small amount (3mm to 6mm thickness) of ice on the unprotected junctures of the horizontal and vertical tail may disturb the airflow in such a way as to cause rudder/rudder pedal oscillations, pitch oscillations and possibly an uncommanded nose down pitch change requiring a higher than normal pull force to counteract. This phenomenon varies with certain combinations of airspeed, power setting, flap deflections, sideslips and type of icing conditions.\n\nThis AD addresses an aerodynamic problem (buffeting and pitch- over) and results from issue of FAA AD 86-01-01 R2 Amendment 39-5316 as amended by 39-5639. It is therefore independent of AD/CESSNA 303/2 Amdt 1 (originating from FAA AD 85-11-05 R1) which addresses a structural problem (flutter).\n\nThis amendment removes the restriction on flight in known icing conditions after incorporation of the modification kits as detailed above.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"Originally this AD banned all Cessna T303 aircraft from flying in icing conditions. Amendment 2 expands the scope to allow an exception: aircraft fitted with specific Cessna stabilizer modification kits (SK 303-39 or SK 303-39A) are now exempt from the prohibition. The legislation has evolved from a blanket ban to a conditional permission system based on hardware modifications."},"complexity_factors":["Very short document (under 400 words)","Only 2 defined modification kits referenced","Simple binary logic: modified vs. unmodified aircraft","No nested exceptions or cross-references to other legislation","Single compliance deadline with no conditional extensions","Plain language background explanation included"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of all Cessna T303 Crusaders to address a hazard where small ice buildup at the tail/fuselage joint can cause severe shaking, nose-down pitching, and violent rudder movements. Unmodified aircraft must display “FLIGHT INTO KNOWN ICING PROHIBITED” and remove any contrary placards; aircraft fitted with modification kit SK 303-39 or SK 303-39A may remove the restriction. All affected aircraft must also have their Flight Manual updated."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment narrows the original blanket restriction by making the prohibition conditional: unmodified T303s must carry a ‘no flight into known icing’ placard and obscure the existing icing‑approval placard, while aircraft fitted with kits SK 303‑39 or SK 303‑39A may remove the prohibition placard. In practical terms, the rule’s scope is reduced for modified aircraft but retained for unmodified ones."},"complexity_factors":["Conditional rule: different obligations depending on whether specific modification kits (SK 303‑39 / SK 303‑39A) are installed","Physical compliance detail: placard text and minimum letter size (≥2.5 mm)","Administrative requirement: must amend Flight Manual and obscure existing operating placard where applicable","Applicability to all serial numbers increases administrative reach but not technical variety","Interaction with other ADs noted (addresses aerodynamic vs structural issues), creating compliance cross-checks","Compliance deadline ('before further flight after 20 February 1986') creates immediate operational effect and enforcement window"],"plain_english_summary":"This directive requires Cessna T303 owners/operators without stabilizer kit SK 303‑39 or SK 303‑39A to fit a visible instrument panel placard reading “FLIGHT INTO KNOWN ICING PROHIBITED” and to cover any existing “approved for flight into icing” placard; aircraft with those kits must remove the prohibition placard. A flight manual amendment is required.\n\nIt affects aircraft owners/operators, who bear placard or modification costs, and responds to a stated safety risk that small tail ice can cause control oscillations and uncommanded pitch; compliance was required before further flight after 20 February 1986."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions","history":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions/history","analysis":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions/analysis","conflicts":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions/conflicts","importantCases":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions/important-cases","documents":"/api/acts/ad-cessna-303-4-amdt-2-prohibition-of-flight-in-known-icing-conditions/documents"}}