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Navigate / EASA / INITIAL AIRWORTHINESS AND ENVIRONMENTAL PROTECTION NOV 2025 / Annex I / SECTION A -- TECHNICAL REQUIREMENTS / SUBPART O -- EUROPEAN TECHNICAL STANDARD ORDER AUTHORISATIONS /

21.A.604 ETSO authorisation for an auxiliary power unit (APU)

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21.A.604 ETSO authorisation for an auxiliary power unit (APU)

Regulation (EU) 2022/201

With regard to an ETSO authorisation for an APU:

(a) by way of derogation from points 21.A.9, 21.A.603, 21.A.610 and 21.A.621, the following points shall apply: points 21.A.15, 21.A.20, 21.A.21, 21.A.31, 21.A.33, 21.A.44, 21.A.47, 21.B.75 and 21.B.80. However, an ETSO authorisation shall be issued in accordance with point 21.A.606 instead of the type-certificate;

(b) by way of derogation from point 21.A.611, the requirements of Subpart D shall apply to the approval of design changes by the APU ETSO authorisation holder and design changes from other applicants classified as a minor change, and the requirements of Subpart E shall apply to the approval of design changes by other applicants classified as a major change. Where the requirements of Subpart E apply, a separate ETSO authorisation shall be issued instead of a supplemental type certificate; and

(c) the requirements of Subpart M shall apply to the approval of repair designs.

Frequently Asked Questions

Regulation (EU) 2022/201.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

Points 21.A.15, 21.A.20, 21.A.21, 21.A.31, 21.A.33, 21.A.44, 21.A.47, 21.B.75, and 21.B.80.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

An ETSO authorisation is issued in accordance with point 21.A.606 instead of the type-certificate.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

The requirements of Subpart D apply to the approval of design changes by the APU ETSO authorisation holder and design changes from other applicants classified as a minor change.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

The requirements of Subpart E apply to the approval of design changes by other applicants classified as a major change. A separate ETSO authorisation is issued instead of a supplemental type certificate.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

The requirements of Subpart M apply to the approval of repair designs.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

No, by way of derogation from point 21.A.611, the requirements of Subpart D and Subpart E apply instead, depending on the classification of the change.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

The requirements of Subpart D apply to design changes from other applicants classified as a minor change.

* Aviation.Bot's Suggestion - Always consult the original regulation for confirmation

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