COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna T303 Series Aeroplanes AD/CESSNA 303/4 Amdt 2 Prohibition of Flight in Known Icing Conditions 10/87 Applicability: Cessna model T303 aeroplanes (all serial numbers). Requirement: 1. For aircraft not modified with the installation of Cessna Modification as detailed in 2 below; (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: "FLIGHT INTO KNOWN ICING PROHIBITED". (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. 2. 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. Remove any placard fitted in accordance with any issue of this Directive. Note: Appropriate Flight Manual amendment will be required for aircraft in either category. Compliance: Before further flight after 20 February 1986. Background: 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. This 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). This amendment removes the restriction on flight in known icing conditions after incorporation of the modification kits as detailed above.