ETSO-C137a

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

IRImplementing rule

ETSO-C137a

Aircraft Portable Megaphones

1 Applicability

This ETSO provides the requirements that portable aircraft megaphones 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 standard is that provided in SAE International’s Aerospace Standard (AS) 4950B, ‘Design and Performance Criteria for Transport Aircraft Portable Megaphones’, dated March 2007, as modified by Appendix 1 to this ETSO.

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.

3.2.2 Embedded Batteries

See CS-ETSO, Subpart A, paragraph 2.8.

4 Marking

4.1 General

See CS-ETSO, Subpart A, paragraph 1.2.

4.2 Specific

None.

5 Availability of Referenced Documents

See CS-ETSO, Subpart A, paragraph 3.

[Amdt ETSO/17]

IR · ETSO-C137a — CS-ETSO · ED Decision 2022/018/R · CS-ETSO Easy Access Rules · EAR revision 1 Oct 2026

AppendixAppendix

Appendix 1 to ETSO-C137aMPS for Aircraft Portable Megaphones

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SAE International’s Aerospace Standard (AS) AS4950B, ‘Design and Performance Criteria for Transport Aircraft Portable Megaphones’, dated March 2007, is modified as per Table 1 below.

Table 1 — Modification of AS4950B, ‘Design and Performance Criteria for Transport Aircraft Portable Megaphones’

Location in AS4950B	Initial AS4950B text	Amending text
3.4.1	All materials used except small parts (knobs, triggers, fasteners, seals, and small electrical parts) that would not contribute significantly to the propagation of a fire shall be self-extinguishing when tested in accordance with the applicable requirements of 14 CFR 25.853.	Compliance shall be shown with the flammability test specified in EUROCAE ED-14G / RTCA DO-160G, Section 26 for Category C: Flammability. If ignition occurs inside or outside the equipment, the equipment shall not propagate the flame.

[Amdt ETSO/17]

APPENDIX · Appendix 1 to ETSO-C137a — CS-ETSO · ED Decision 2022/018/R · CS-ETSO Easy Access Rules · EAR revision 1 Oct 2026

All rules in SUBPART B – LIST OF ETSOs

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.

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