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To ensure that takeoff is performed with a clean aircraft, an external inspection has to be carried-out, bearing in mind that such phenomenon as clear-ice cannot be visually detected. Strict procedures and checks apply. In addition, responsibilities in accepting the aircraft status are clearly defined.
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If the aircraft is not clean prior to takeoff it has to be de-iced. De-icing procedures ensure that all the contaminants are removed from aircraft surfaces.
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If the outside conditions are likely to lead to an accumulation of precipitation before takeoff, the aircraft must be anti-iced. Anti-icing procedures provide protection against the accumulation of contaminants during a limited timeframe, referred to as holdover time.
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The most important aspect of anti-icing procedures is the associated holdover-time. This describes the protected time period. The holdover time depends on the weather conditions (precipitation and OAT) and the type of fluids used to anti-ice the aircraft.
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Different types of fluids are available (Type I, II, III and IV). They differ by their chemical composition, viscosity (capacity to adhere to the aircraft skin) and their thickness (capacity to absorb higher quantities of contaminants) thus providing variable holdover times.
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Published Holdover tables should be used for guidance only, as many parameters may influence their efficiency -like severe weather conditions, high wind velocity, jet blast etc and considerably effect protection time in unpredictable ways.
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There are a variety of ways in which aircraft on the ground can be de-iced; using de-icing fluids, hot air, manual methods. Approved methods need to be used for de-icing on the ground.
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Anti-icing is carried out using approved fluids.
DE-ICING OPERATIONS MANAGEMENT PLAN
6.1 AIR INDIA shall enter into an agreement with an authorized agency to de-ice/anti-ice its aircraft whenever required. The Exec. Director Operations Air India shall ensure that the contracted agency is able to provide de-icing in accordance with the Air India De-ice/Anti-Ice Operations Manual
6.2 System organization
Issue II 02.07.2009 Rev. 0
RESPONSIBILITY: THE DE-ICING/ANTI-ICING DECISION
7.1 Maintenance responsibility:
The information report (de-icing/anti-icing code) given to the cockpit is a part of the technical airworthiness of the aircraft. The person releasing the aircraft is responsible for the performance and verification of the results of the de/anti-icing treatment. The responsibility of accepting the performed treatment lies, however, with the Commander.
7.2 Operational responsibility:
7.2.1 The general transfer of operational responsibility takes place at the moment the aircraft starts moving by its own power.
7.3 Maintenance / ground crew decision 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：Cold Weather Deicing/Anti-icing Manual 寒冷天气除防冰手册 Operations Manual Training 运行手册培训(7)
