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CS 25.856 Thermal/acoustic insulation materials

Large Aeroplanes (CS-25) · CS-25 · EAR revision 26 Jan 2023

IRImplementing rule

CS 25.856Thermal/acoustic insulation materials

(See AMC 25.856(a))

(a)Thermal/acoustic insulation material installed in the fuselage must meet the flame propagation test requirements of Part VI of Appendix F to CS-25, or other approved equivalent test requirements. This requirement does not apply to “small parts”, as defined in Part I of Appendix F to CS-25. (See AMC 25.856(a))

(b)For aeroplanes with a passenger capacity of 20 or greater, thermal/acoustic insulation materials (including the means of fastening the materials to the fuselage) installed in the lower half of the aeroplane fuselage must meet the flame penetration resistance test requirements of Part VII of Appendix F to CS-25, or other approved equivalent test requirements. This requirement does not apply to thermal/acoustic insulation installations that the Agency finds would not contribute to fire penetration resistance. (See AMC 25.856(b))

[Amdt 25/6]

[Amdt 25/18]

IR · CS 25.856 — CS-25 · ED Decision 2016/010/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

AMCAcceptable means of compliance

AMC 25.856(a)Thermal/acoustic insulation materials: Flame propagation resistance

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FAA Advisory Circular 25.856-1 Thermal/Acoustic Insulation Flame Propagation Test Method Details, dated 24/06/2005, is accepted by the Agency as providing acceptable means of compliance with CS 25.856(a) and Part VI of Appendix F to CS-25.

[Amdt 25/6]

AMC · AMC 25.856(a) — CS-25 · ED Decision 2009/010/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

AMCAcceptable means of compliance

AMC 25.856(b)Thermal/acoustic insulation materials: Flame penetration (Burnthrough) resistance

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FAA Advisory Circular 25.856-2A Installation of Thermal/Acoustic Insulation for Burnthrough Protection, dated 29/07/2008, is accepted by the Agency as providing acceptable means of compliance with CS 25.856(b) and Part VII of Appendix F to CS-25.

[Amdt 25/6]

AMC · AMC 25.856(b) — CS-25 · ED Decision 2009/010/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

All rules in SUBPART D – DESIGN AND CONSTRUCTION

Consolidated from the EASA Easy Access Rules (revision 26 Jan 2023, extracted 17 Aug 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.

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