---
title: "CS 26.307(a)(i),(ii) and (b) List of fatigue-critical modified structure — ADDITIONAL AIRWORTHINESS SPECIFICATIONS FOR OPERATIONS, Part-26 · Avioverse"
description: "Compliance with points 26.307(a)(i) and (ii) and 26.307(b) of Part-26 is demonstrated when a list of the fatigue-critical modified structures (FCMSs)…"
url: "https://avioverse.aero/regulations/easa/additional-airworthiness/additional-airworthiness-specifications-for/subpart-b/cs-26-307-a-i-ii-and-b-list-of-fatigue-critical-modified-structure"
---

# CS 26.307(a)(i),(ii) and (b) List of fatigue-critical modified structure

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

IR Implementing rule

## CS 26.307(a)(i),(ii) and (b) List of fatigue-critical modified structure

Compliance with points 26.307(a)(i) and (ii) and 26.307(b) of Part-26 is demonstrated when a list of the fatigue-critical modified structures (FCMSs) exists that has been identified in compliance with AMC 20-20A Appendix 3 paragraph 4, and which clearly describes the location and the extent of the FCMS.

\[Issue: 26/3]

IR — Regulation (EU) 2015/640 · ED Decision 2020/023/R · Part-26 Easy Access Rules · EAR revision 20 Mar 2026

[All rules in SUBPART B — AEROPLANES](https://avioverse.aero/regulations/easa/additional-airworthiness/additional-airworthiness-specifications-for/subpart-b)

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.