ETSO-C117b

• ED Decision 2020/011/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

#### ETSO-C117b *ED Decision 2020/011/R* ##### **Airborne Wind shear Warning and Escape Guidance Systems (Reactive Type) for Transport Aeroplanes** **1 Applicability** This ETSO provides the requirements that airborne wind shear warning and escape guidance systems (reactive type) for transport aeroplanes that are designed and manufactured on or after the date of this ETSO, must meet in order to be identified with the applicable ETSO marking. It is not applicable to systems that look ahead to sense wind shear conditions before the phenomenon is encountered, nor to systems that use atmospheric and/or other data to predict the likelihood of a wind shear alert. [Appendix 1](#_DxCrossRefBm920220830) to this ETSO describes the MPS for the airborne wind shear warning and escape guidance systems for transport category aeroplanes. [Appendix 2](#_DxCrossRefBm920220829) to this ETSO describes the wind field models used to evaluate the performance of a wind shear warning and escape guidance system. [Appendix 3](#_DxCrossRefBm920220828) to this ETSO describes the conversion of the velocity equations in Appendix 2 to rectangular coordinates. [Appendix 4](#_DxCrossRefBm920220827) to this ETSO contains data that defines the Dryden turbulence model and the discrete gust model used in conducting the required wind shear alert tests. [Appendix 5](#_DxCrossRefBm920220826) to this ETSO describes shear intensity. [Appendix 6](#_DxCrossRefBm920220825) to this ETSO provides a sample computer listing for a simplified aeroplane simulation model for evaluating the effectiveness of various guidance schemes. **2 Procedures** 2.1 General The applicable procedures are detailed in CS-ETSO, [Subpart A](#_DxCrossRefBm920220672) 2.2 Specific None. **3 Technical Conditions** 3.1 General 3.1.1 Minimum Performance Standard The applicable standards are provided in the attached Appendix 1. 3.1.2 Environmental Standard See CS-ETSO, Subpart A, paragraph 2.1 3.1.3 Computer Software See CS-ETSO, Subpart A, paragraph 2.2. 3.1.4 Airborne Electronic Hardware See CS-ETSO, Subpart A, paragraph 2.3. 3.2 Specific 3.2.1 Failure Condition Classification See CS-ETSO, Subpart A, paragraph 2.4. A failure of the function defined in 3.1.1 above that results in an unannunciated malfunction or a missed wind shear detection is a major failure condition. A loss of the function defined in 3.1.1 above is a minor failure condition. **4 Marking** 4.1 General See CS-ETSO, Subpart A, paragraph 1.2. 4.2 Specific None. **5 Availability of Referenced Documents** See CS-ETSO, Subpart A, paragraph 3. [Amdt ETSO/16]