Appendix 2 - Artificial Ice Shapes

• ED Decision 2015/008/R found in: CS-25 Amdt 27 - Large Aeroplanes (Jan 2023)

Appendix 2 – Artificial Ice Shapes ED Decision 2015/008/R A2.1 General. A2.1.1 The artificial ice shapes used for flight testing should be those which have the most adverse effects on handling characteristics. If analytical data show that other reasonably expected ice shapes could be generated which could produce higher performance decrements, then the ice shape having the most adverse effect on handling characteristics may be used for performance tests provided that any difference in performance can be conservatively taken into account. A2.1.2 The artificial shapes should be representative of natural icing conditions in terms of location, general shape, thickness and texture. Following determination of the form and surface texture of the ice shape under paragraph A2.2, a surface roughness for the shape should be agreed with the Agency as being representative of natural ice accretion. A2.1.3 "Sandpaper Ice" is addressed in paragraph A2.3. A2.2 Shape and Texture of Artificial Ice. A2.2.1 The shape and texture of the artificial ice should be established and substantiated by agreed methods. Common practices include: — use of computer codes, — flight in measured natural icing conditions, — icing wind tunnel tests, and — flight in a controlled simulated icing cloud (e.g. from an icing tanker). A2.2.2 In absence of another agreed definition of texture the following may be used: — roughness height: 3 mm — particle density: 8 to 10/cm² A2.3 "Sandpaper Ice." A2.3.1 "Sandpaper Ice" is the most critical thin, rough layer of ice. Any representation of "Sandpaper Ice" (e.g. carborundum paper no. 40) should be agreed by the Agency. A2.3.2 Because sandpaper ice must be considered in the basic icing certification within the Appendix C environmental icing envelope, it does not need to be considered for certification of flight in Appendix O icing conditions. A2.3.3 The spanwise and chordwise coverage should be consistent with the areas of ice accretion determined for the conditions of CS-25, [Appendix C](#_DxCrossRefBm1709820681) except that, for the zero g pushover manoeuvre of paragraph 6.9.4 of this AMC, the "Sandpaper Ice" may be restricted to the horizontal stabiliser if this can be shown to be conservative. [Amdt 25/3] [Amdt 25/16]