---
title: "CS 26.307(a)(iii) and (c) Damage tolerance data for existing changes to the FCS — ADDITIONAL AIRWORTHINESS SPECIFICATIONS FOR OPERATIONS, Part-26 · Avioverse"
description: "Compliance with the fatigue and damage tolerance evaluation required by point 26.307 (a)(iii) and (c) of Part-26 is demonstrated by complying with CS…"
url: "https://avioverse.aero/regulations/easa/additional-airworthiness/additional-airworthiness-specifications-for/subpart-b/cs-26-307-a-iii"
---

# CS 26.307(a)(iii) and (c) Damage tolerance data for existing changes to the FCS

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

IR Implementing rule

## CS 26.307(a)(iii) and (c) Damage tolerance data for existing changes to the FCS

Compliance with the fatigue and [damage tolerance evaluation](https://avioverse.aero/glossary/easa/damage-tolerance-evaluation) required by point 26.307 (a)(iii) and (c) of Part-26 is demonstrated by complying with CS 25.571 Amendment 19 or subsequent amendment, or with the following:

(a) The fatigue and damage tolerance evaluation is in accordance with the damage tolerance requirements of the applicable certification basis, except as provided in point (b) of this CS.

(b) For aeroplanes certified on the basis of JAR-25 Change 6 or 14 CFR §25.571 Amendment 44 or equivalent, or earlier amendments, the fatigue and damage tolerance evaluation of the change is in accordance with JAR-25 Change 7 or 14 CFR §25.571 Amendment 45, or equivalent, or later amendments, except that residual strength loads may be based upon the fail-safe load cases of the original certification basis.

\[Issue: 26/3]

IR · CS 26.307(a)(iii) — 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.