AMC 25.773(b)(1)(ii) Pilot compartment view in icing conditions

• ED Decision 2016/010/R found in: CS-25 Amdt 27 - Large Aeroplanes (Jan 2023)

AMC 25.773(b)(1)(ii) Pilot compartment view in icing conditions ED Decision 2016/010/R [CS 25.773(b)(1)(ii)](#_DxCrossRefBm1709821185) requires that the aeroplane have a means of maintaining a clear portion of windshield in the icing conditions defined in [Appendix C](#_DxCrossRefBm1709820681) and in certain [Appendix O](#_DxCrossRefBm1709820665) icing conditions (corresponding to the [CS 25.1420](#_DxCrossRefBm1709820673) certification option selected). The effectiveness of all cockpit windows and windshield ice and precipitation protective systems should be established within relevant icing environment. Sufficient tests, including flight test in natural or simulated Appendix C icing conditions, should be performed to validate the performance prediction done by analysis. When thermal ice protection systems are used (e.g. electrical heating system), a thermal analysis should be conducted to substantiate the selected nominal heated capacity. Past certification experience has shown that a nominal heating capacity of 70 W/dm2 provide adequate protection in icing conditions; such value, if selected, should anyway be substantiated by the thermal analysis. The applicant should conduct dry air flight tests to verify the thermal analysis. Measurements of both the inner and outer surface temperature of the protected windshield area may be needed to verify the thermal analysis. The thermal analysis should show that the windshield surface temperature is sufficient to maintain anti-icing capability without causing structural damage to the windshield. When anti-icing fluid systems are used, tests shall be performed to demonstrate that the fluid does not become opaque at low temperatures. The AFM should include information advising the flight crew how long it will take to deplete the amount of fluid remaining in the reservoir. An evaluation of visibility, including distortion effects through the protected area, should be made for both day and night operations. In addition, the size and location of the protected area should be reviewed to confirm that it provides adequate visibility for the flight crew, especially during the approach and landing phases of flight. For showing compliance with the CS-25 certification specifications relative to SLD icing conditions represented by Appendix O, the applicant may use a comparative analysis. AMC 25.1420(f) provides guidance for comparative analysis. [Amdt 25/16] [Amdt 25/18]