Originally Posted by jcjeant
Will be not astonished if one day EASA publish a notice about the "discovery" of the wheel ...
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Following the ATR 72 accident, the National Transportation Safety Board in the USA (NTSB) recommended updating aeroplanes icing conditions specifications. Although some knowledge existed at this date about severe icing conditions, including SLD, it was not possible to immediately update the icing environment in the Certification Specifications, because there was a need to identify in detail the parameters of the relevant environmental envelopes applicable to aircraft operations and to accurately assess the associated safety risk; in addition, the methods of compliance by aircraft manufacturers with potential new icing environment requirements had to be investigated (capabilities in terms of engineering tools, ground test facilities, flight tests). This was recognised as a very complex task requiring various expertises. Therefore, an Aviation Rulemaking Advisory Committee (ARAC) was tasked by the Federal Aviation Administration (FAA) in December 1997, through its Ice Protection Harmonization Working Group (IPHWG), to perform the following actions:
Define an icing environment that includes SLDs;
Consider the need to define a mixed phase icing environment (supercooled liquid and ice crystals);
Devise requirements to assess the ability of an aeroplane to either safely operate without restrictions in these conditions or safely operate until it can exit these conditions;
Study the effects icing requirement changes could have on FAR/JAR 25.773 Pilot compartment view, 25.1323 Airspeed indicating system, and 25.1325 Static pressure systems.
Consider the need for a regulation on ice protection for angle of attack probes.
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The proposed rule is based on the recommendations of the ARAC group. The ARAC IPHWG task 2 report rev A along with the task 2 phase IV review (submitted on 29 June 2009) are available on the FAA website under Regulations & Policies\Advisory and Rulemaking Committees\Advisory Committees\Aviation Rulemaking Advisory Committee\Transport Airplane and Engine\Active Working Groups\Ice Protection Harmonization.
Regards,
HN39