---
title: "ETSO-C56b A1 — CS-ETSO · Avioverse"
description: "Engine-driven Direct Current Generators/Starter-generators 1 Applicability This ETSO gives the requirements which engine-driven direct current…"
url: "https://avioverse.aero/regulations/easa/cs-etso/subpart-b/etso-c56b"
---

# ETSO-C56b A1

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

IR Implementing rule

## ETSO-C56b A1

Engine-driven Direct Current Generators/Starter-generators

1 Applicability

This ETSO gives the requirements which engine-driven direct current generators/starter-generators 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

Standards set forth in the SAE Aerospace Standard (AS) document: AS8020, "Engine Driven D.C. Generators/Starter-Generators and Associated Voltage Regulators", dated January 1980 (and reaffirmed by SAE in August 1991).

3.1.2 Environmental standard

See CS-ETSO, Subpart A, paragraph 2.1.

3.1.3 Software

If the Engine Driven Direct Current Generator / Starter Generator and the associated voltage regulators include a digital computer, see CS-ETSO, Subpart A, Paragraph 2.2, for software development.

3.1.4 Airborne electronic hardware

See CS-ETSO, Subpart A, paragraph 2.3.

3.2 Specific

None.

4 Marking

4.1 General

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

4.2 Specific

In addition to the information specified in §4.1, the following information is required:

(1) Means of indicating if the article is a D.C. generator or a D.C. starter-generator;

(2) Nominal power output (electrical voltage and watts);

(3) Mechanical power input requirements (pad requirements).

5 Availability of referenced document

See CS-ETSO, Subpart A, paragraph 3.

\[Amdt ETSO/3]

\[Amdt ETSO/8]

IR · ETSO-C56b — CS-ETSO · ED Decision 2013/012/R · 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.