Appendix 1 to ETSO-C87a - Modifications and Additions to EUROCAE ED-30 for Minumum Performance Standards for Low-Range Radio Altimeters

• ED Decision 2013/012/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

###### Appendix 1 to ETSO-C87a – Modifications and Additions to EUROCAE ED-30 for Minumum Performance Standards for Low-Range Radio Altimeters *ED Decision 2013/012/R* **1.0. ED-30 REQUIREMENT MODIFICATIONS** 1.1. **ED-30 Paragraph 1.3 (Radio Altimeters with Auto-Surveillance).** [ETSO-C87a](#_DxCrossRefBm920220786) does not include a separate category for monitoring. Design the radio altimeter to support the failure condition classification of the intended installation. 1.2. **ED-30 Paragraph 2.2 (Transmitter Operating Frequency).** Add the following requirement to ED-30, paragraph 2.2: The radio altimeter shall meet the International Telecommunication Union (ITU) regulations, if applicable. 1.3. **ED-30 Paragraph 2.5 (Failure Warning).** Add the following sentence to the beginning of ED-30, paragraph 2.5, to clarify that a failure detection system is required: ‘A failure detection system must be incorporated in the equipment to indicate to the pilot, and to any systems utilizing the radio altimeter data, of a failure of the radio altimeter to accomplish its intended function because of the following conditions: (1) Loss of power, and (2) Loss of signal or altitude sensing capability when within the manufacturer’s stated operating altitude range.’ 1.4. **ED-30 Paragraph 3.2.2 (Category A2).** [ETSO-C87a](#_DxCrossRefBm920220786) does not include Category A2. If alternate accuracy requirements not meeting the requirements of paragraph 3.2.1 are desired, the applicant should apply for a deviation in accordance with paragraph 3.g. of this ETSO. 1.5. **ED-30 Paragraph 3.2.4 (Category C).** [ETSO-C87a](#_DxCrossRefBm920220786) does not include Category C. If the radio altimeter has been designed and tested to tighter accuracy requirements, include the design information, test results, and limitations with the application for ETSO and document the performance in the installation manual. 1.6. **ED-30 (Appendix).** The ED-30 appendix references TSO-C87 and RTCA/DO-123 for external loop loss standards. As TSO-C87 and DO-123 are no longer current, reference RTCA/DO-155, Minimum Performance Standards Airborne Low-Range Radar Altimeters, Appendix B, for external loop loss standards instead. **2.0. REQUIREMENT ADDITIONS to ED-30: Rate Data.** The equipment need not provide a rate data output as a condition of compliance with this minimum performance standard. Altimeters with rate outputs must meet the following accuracy requirements for at least 95 percent of all observations for heights from the terrain to the antenna: <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <col/> <thead> <tr> <td bgcolor="#808080" colspan="3" valign="top"><p align="center"> <b>RATE DATA </b> </p> </td> </tr> <tr valign="top"> <td bgcolor="#808080"><p align="center"> <b>Height (ft) </b> </p> </td> <td bgcolor="#808080"><p align="center"> <b>Range (ft/sec) </b> </p> </td> <td bgcolor="#808080"><p align="center"> <b>Accuracy (ft/sec) </b> </p> </td> </tr> </thead> <tbody> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 3–100 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> 0–15 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> ± (1.5 ft.+ 0.01 h + 0.1 /r/) </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 100–200 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> 0–20 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> ± (2.0 ft.+ 0.01 h + 0.1 /r/) </p> </td> </tr> </tbody> </table> Where: h = altitude in feet; and /r/ = absolute value of rate (feet/sec.) [Amdt ETSO/8]