---
title: "CS 26.425 Provision of substantiated sea conditions — ADDITIONAL AIRWORTHINESS SPECIFICATIONS FOR OPERATIONS, Part-26 · Avioverse"
description: "Compliance with point 26.425 of Part-26 is demonstrated by complying with CS 27.1587(b)(3) of CS27 at Amendment 5 or later, or the equivalent, or CS…"
url: "https://avioverse.aero/regulations/easa/additional-airworthiness/additional-airworthiness-specifications-for/subpart-c/cs-26-425"
---

# CS 26.425 Provision of substantiated sea conditions

ADDITIONAL AIRWORTHINESS SPECIFICATIONS FOR OPERATIONS · Regulation (EU) 2015/640 · EAR revision 20 Mar 2026

IR Implementing rule

## CS 26.425 Provision of substantiated sea conditions

Compliance with point 26.425 of Part-26 is demonstrated by complying with CS 27.1587(b)(3) of CS27 at Amendment 5 or later, or the equivalent, or CS 29.1587(c) of CS-29 at Amendment 5 or later or the equivalent respectively.

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IR · CS 26.425 — Regulation (EU) 2015/640 · ED Decision 2022/019/R · Part-26 Easy Access Rules · EAR revision 20 Mar 2026

[All rules in SUBPART C — HELICOPTERS](https://avioverse.aero/regulations/easa/additional-airworthiness/additional-airworthiness-specifications-for/subpart-c)

Consolidated from the EASA Easy Access Rules (revision 20 Mar 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.