ETSO-C20a

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

#### ETSO-C20a *ED Decision 2020/011/R* ##### **Combustion Heaters and Accessories** **1 Abpplicability** This ETSO provides the requirements which combustion heaters and accessories 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. **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 Basic 3.1.1 Minimum Performance Standard The applicable standards are those provided in SAE International’s Aerospace Standard AS8040B, Heater, Aircraft, Internal Combustion Heat Exchanger Type, dated 14 February 2013, as amended by Appendices [1](#_DxCrossRefBm920220703) and [2](#_DxCrossRefBm920220702) to this ETSO. 3.1.1.1 Functionality This standard in this ETSO applies to equipment that is intended to provide heated air for civil aircraft. Note: For combustion heaters and accessories, the maintenance and inspection items contained in the instructions for continued airworthiness play an important role in preventing failures that result in combustion by-products entering the cabin/flight deck. 3.1.2 Environmental Standard The required performance under the test procedures in SAE AS8040B, Heater, Aircraft, Internal Combustion Heat Exchanger Type, dated 14 February 2013, as amended by Appendix 1 to this ETSO, using standard environmental conditions and test procedures that are appropriate for airborne equipment, shall be demonstrated. 3.1.3 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 (1) A failure of the function defined in paragraph 3.1.1.1 of this ETSO is a major failure condition. (2) A loss of the function defined in paragraph 3.1.1.1 of this ETSO is a minor failure condition. (3) Design the system to at least fulfil these failure conditions above. **4 Marking** 4.1 General See CS-ETSO, Subpart A, paragraph 1.2. 4.2 Specific If the article includes software and/or airborne electronic hardware, then the part numbering scheme for the article must identify the configuration of both the software and the airborne electronic hardware. The part numbering scheme can use separate, unique part numbers for the software, the hardware, and the airborne electronic hardware. If the combustion heater includes a deviation from this ETSO, the marking must include a means to indicate that a deviation was granted. **5 Availability of Referenced Document** See CS-ETSO, Subpart A, paragraph 3. [Amdt ETSO/16]