---
title: "ETSO-2C519a — CS-ETSO · Avioverse"
description: "EMERGENCY BREATHING SYSTEMS (EBSs) 1 Applicability This ETSO provides the requirements which emergency breathing systems (EBSs) for operations to or from…"
url: "https://avioverse.aero/regulations/easa/cs-etso/subpart-b/etso-2c519a"
---

# ETSO-2C519a

European Technical Standard Orders (CS-ETSO) · CS-ETSO · EAR revision 1 Oct 2026

IR Implementing rule

## ETSO-2C519a

EMERGENCY BREATHING SYSTEMS (EBSs)

1 Applicability

This ETSO provides the requirements which emergency breathing systems (EBSs) for operations to or from helidecks that are located in hostile sea areas (as defined in Annex I (‘Definitions for terms used in Annexes II to V’) to Commission Regulation (EU) No 965/2012) 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.

2.2 Specific

None.

3 Technical Conditions

3.1 Basic

3.1.1 Minimum Performance Standard

The applicable standards are those provided in AeroSpace and Defence Industries Association of Europe — Standardization (ASD-STAN) document prEN4856, edition P2, dated June 2022.

3.1.2 Environmental Standard

See CS-ETSO, Subpart A, paragraph 2.1.

3.1.3 Software

None.

3.1.4 Airborne Electronic Hardware

None.

3.2 Specific

3.2.1 Failure Condition Classification

None.

4 Marking

4.1 General

See CS-ETSO, Subpart A, paragraph 1.2.

4.2 Specific

The specific marking requirements are detailed in ASD-STAN document prEN4856, edition P2, dated June 2022.

5 Availability of Referenced Documents

See CS-ETSO, Subpart A, paragraph 3.

\[Amdt ETSO/16]

\[Amdt ETSO/18]

IR · ETSO-2C519a — CS-ETSO · CS-ETSO Easy Access Rules · EAR revision 1 Oct 2026

[All rules in SUBPART B – LIST OF ETSOs](https://avioverse.aero/regulations/easa/cs-etso/subpart-b)

Consolidated from the EASA Easy Access Rules (revision 1 Oct 2026, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.