ETSO-C178a

• ED Decision 2022/018/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

#### ETSO-C178a *ED Decision 2022/018/R* ##### Aircraft Circuit Breakers **1 Applicability** This ETSO provides the requirements that aircraft circuit breakers 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 Table 1 for the intended equipment class: ***Table 1 — Equipment class standards*** <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <col/> <thead> <tr valign="top"> <td bgcolor="#808080"><p align="center"> <b>Equipment Class</b></p> </td> <td bgcolor="#808080"><p align="center"> <b>Equipment Type</b></p> </td> <td bgcolor="#808080"><p align="center"> <b>Minimum Performance Standards</b></p> </td> </tr> </thead> <tbody> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 1</p> </td> <td bgcolor="#d9d9d9"><p align="left"> Alternating Current (AC) Arc Fault Circuit Breakers</p> </td> <td bgcolor="#d9d9d9"><p align="left"> SAE Aerospace Standard (AS) AS5692A, ‘ARC Fault Circuit Breaker (AFCB), Aircraft, Trip-Free Single Phase and Three Phase 115 VAC, 400 Hz - Constant Frequency’, dated December 2009</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 2</p> </td> <td bgcolor="#d9d9d9"><p align="left"> Direct Current (DC) Arc Fault Circuit Breakers</p> </td> <td bgcolor="#d9d9d9"><p align="left"> SAE Aerospace Standard (AS) AS6019, ‘ARC Fault Circuit Breaker (AFCB), Aircraft, Trip-Free 28 VDC’, dated June 2012</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 3</p> </td> <td bgcolor="#d9d9d9"><p align="left"> AC or DC Thermal Circuit Breakers</p> </td> <td bgcolor="#d9d9d9"><p align="left"> SAE Aerospace Standard (AS) AS58091A, ‘Circuit Breakers, <br/> Trip-Free, Aircraft General Specification For’, dated May 2012</p> </td> </tr> </tbody> </table> 3.1.2 Environmental Standard See CS-ETSO, Subpart A, paragraph 2.1. 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 See CS-ETSO, Subpart A, paragraph 2.4. **4 Marking** 4.1 General See CS-ETSO, Subpart A, paragraph 1.2. 4.2 Specific The class of the equipment shall be legibly and permanently marked. **5 Availability of referenced documents** See CS-ETSO, Subpart A, paragraph 3. [Amdt ETSO/8] [Amdt ETSO/17]