---
title: "ETSO-2C503a — CS-ETSO · Avioverse"
description: "ROTORCRAFT IMMERSION SUITS FOR OPERATIONS TO OR FROM HELIDECKS LOCATED IN A HOSTILE SEA AREA 1 Applicability This ETSO gives the requirements which…"
url: "https://avioverse.aero/regulations/easa/cs-etso/subpart-b/etso-2c503a"
---

# ETSO-2C503a

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

IR Implementing rule

## ETSO-2C503a

ROTORCRAFT IMMERSION SUITS FOR OPERATIONS TO OR FROM HELIDECKS LOCATED IN A

HOSTILE SEA AREA

1 Applicability

This ETSO gives the requirements which immersion suits for use on rotorcraft operating to or from helidecks located in a hostile sea area (as defined in Annex I (‘Definitions for terms used in Annexes II to V’) to Commission Regulation (EU) No 965/2012) that are 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

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 ASD-STAN document prEN4863, edition P1, dated May 2022.

3.1.2 Environmental Standard

None.

3.2 Specific

None.

4 Marking

4.1 General

Marking is detailed in CS-ETSO Subpart A paragraph 1.2.

4.2 Specific

The specific marking requirements are detailed in ASD-STAN document prEN4863, edition P1, dated May 2022.

5 Availability of Referenced Document

See CS-ETSO Subpart A paragraph 3.

\[Amdt ETSO/1]

\[Amdt ETSO/18]

IR · ETSO-2C503a — 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.