AIRWORTHINESS DIRECTIVE For 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 CAR 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. Harbin Y12 Series Aeroplanes AD/Y12/8 Aircraft Flight Manual, Flight into Icing Conditions 3/2003 Applicability: All Y12II aeroplanes. Requirement: 1. Revise the CAAC and FAA approved Airplane Flight Manual (AFM) by incorporating the following into the Limitations Section of the AFM: "Except for certain phases of flight where the AFM specifies that de-icing boots should not be used (e.g. take-off, final approach, and landing), compliance with the following is required. 1. Wing and Tail Leading Edge Pneumatic De-icing Boot System, if installed, must be activated: 1. At the first sign of ice formation anywhere on the aircraft, or upon annunciation from an ice detector system, whichever occurs first; and ii. The system must either be continued to be operated in the automatic cycling mode, if available; or the system must be manually cycled as needed to minimize the ice accretion on the airframe. b. The wing and tail leading edge pneumatic de-icing boot system may be deactivated only after leaving icing conditions and after the airplane is determined to be clear of ice." 2. Revise the CAAC and FAA approved Airplane Flight Manual (AFM) by incorporating the following into the Limitations Section of the AFM: "WARNING Severe icing may result from environmental conditions outside of those for which the airplane is certificated. Flight in freezing drizzle, or mixed icing conditions (supercooled liquid water and ice crystals) may result in ice build-up on protected surfaces exceeding the capability of the ice protection system, or may result in ice forming aft of the protected surfaces. This ice may not be shed using the ice protection systems, and may seriously degrade the performance and controllability of the airplane. Harbin Y12 Series Aeroplanes AD/Y12/8 (Continued) During flight, severe icing conditions that exceed those for which the airplane is certificated shall be determined by the following visual cues. If one or more of these visual cues exists, immediately request priority handling from Air Traffic Control (ATC) to facilitate a route or an altitude change to exit the icing conditions: 1. Unusually extensive ice accumulation on the airframe and windshield in areas not normally observed to collect ice. b. Accumulation of ice on the lower surface of the wing aft of the protected area. c. Accumulation of ice on the engine nacelles and propeller spinners farther aft than normally observed. Since the autopilot, when installed and operating, may mask tactile cues that indicate adverse changes in handling characteristics, use of the autopilot is prohibited when any of the visual cues specified above exist, or when unusual lateral trim requirements or autopilot trim warnings are encountered while the airplane is in icing conditions. All wing icing inspection lights must be operative prior to flight into known or forecast icing conditions at night. (NOTE: This supersedes any relief provided by the Master Minimum Equipment List)." 3. Revise the CAAC and FAA-approved AFM by incorporating the following into the Normal Procedures Section of the AFM: "THE FOLLOWING WEATHER CONDITIONS MAY BE CONDUCIVE TO SEVERE IN FLIGHT ICING 1. Visible rain at temperatures below 0 degrees Celsius ambient air temperature. b. Droplets that splash or splatter on impact at temperature below 0 degrees Celsius ambient air temperature. PROCEDURES FOR EXITING THE SEVERE ICING ENVIRONMENT: These procedures are applicable to all flight phases from takeoff to landing. Harbin Y12 Series Aeroplanes AD/Y12/8 (Continued) Monitor the ambient air temperature. While severe icing may form at temperature as cold as -18 degrees Celsius, increased vigilance is warranted at temperatures around freezing with visible moisture present. If the visual cues specified in the Limitations Section of the AFM for identifying severe icing conditions are observed, accomplish the following: 1. Immediately request priority handling from Air Traffic Control to facilitate a route or altitude change to exit the severe icing conditions in order to avoid extended exposure to flight conditions more severe than those for which this airplane has been certificated. b. Avoid abrupt and excessive manoeuvring that may exacerbate control difficulties. c. Do not engage the autopilot. d. If the autopilot is engaged, hold the control wheel firmly and disengage the autopilot. e. If an unusual roll response or uncommanded roll control movement is observed, reduce the angle-of-attack. f. Do not extend flaps when holding in icing conditions. Operation with flaps extended can result in a reduced wing angle-of-attack, with the possibility of ice forming on the lower surface further aft on the wing than normal, possibly aft of the protected area. g. If the flaps are extended, do not retract them until the airframe is clear of ice. h. Report these weather conditions to Air Traffic Control." Note 1: China AD CAD2000-Y012-02 Amdt 39-2824 refers. Note 2: Operators should initiate action to notify and ensure that flight crew members are aware of the change. Note 3: A copy of this Directive maybe inserted in the AFM to accomplish the amendment to the AFM. Compliance: Unless previously accomplished, within 20 days of the effective date of this Directive. This Airworthiness Directive becomes effective on 20 March 2003. Harbin Y12 Series Aeroplanes AD/Y12/8 (Continued) Background: This Directive is issued to minimise the potential hazards associated with operating the aircraft in severe icing conditions by providing more clearly defined procedures and limitations associated with such conditions. James Coyne Delegate of the Civil Aviation Safety Authority 3 February 2003 The above AD is notified in the Commonwealth of Australia Gazette on 26 February 2003.