26.156 Thermal or acoustic insulation materials

• Regulation (EU) 2019/133 found in: CS-26 Additional Airworthiness Specifications for Operations (No 2015/640) Part-26 (Mar 2023)
• Regulation (EU) 2024/2954 found in: CS-26 Additional Airworthiness Specifications for Operations (Part-26) (Oct 2025)

26.156 Thermal or acoustic insulation materials Regulation (EU) 2019/133 Operators of large aeroplanes used in commercial air transport, type certified on or after 1 January 1958, shall ensure that: (a) for aeroplanes for which the first individual certificate of airworthiness is issued before 18 February 2021, when new thermal or acoustic insulation materials are installed as replacements on or after 18 February 2021, those new materials have flame propagation resistance characteristics which prevent or reduce the risk of flame propagation in the aeroplane; (b) for aeroplanes for which the first individual certificate of airworthiness is issued on or after 18 February 2021, thermal and acoustic insulation materials have flame propagation resistance characteristics which prevent or reduce the risk of flame propagation in the aeroplane; (c) for aeroplanes for which the first individual certificate of airworthiness is issued on or after 18 February 2021 and with a passenger capacity of 20 or more, thermal and acoustic insulation materials (including the means of fastening the materials to the fuselage) installed in the lower half of the aeroplane have flame penetration resistance characteristics which prevent or reduce the risk of flame penetration into the aeroplane after an accident and which ensure survivable conditions in the cabin for a time needed to evacuate the aeroplane. #### 26.156 Thermal or acoustic insulation materials *Regulation (EU) 2024/2954* Operators of large aeroplanes that are used in commercial air transport, and that were type certified on or after 1 January 1958, shall ensure that: (a) for large aeroplanes for which the first individual certificate of airworthiness was issued before 18 February 2021, when new thermal or acoustic insulation materials are installed as replacements on or after 18 February 2021, those new materials have flame propagation resistance characteristics which prevent or reduce the risk of flame propagation in the aeroplane; (b) for large aeroplanes for which the first individual certificate of airworthiness was issued on or after 18 February 2021, thermal and acoustic insulation materials have flame propagation resistance characteristics which prevent or reduce the risk of flame propagation in the aeroplane; (c) for large aeroplanes for which the first individual certificate of airworthiness was issued on or after 18 February 2021 and with a passenger capacity of 20 or more, thermal and acoustic insulation materials (including the means of fastening the materials to the fuselage) installed in the lower half of the aeroplane have flame penetration resistance characteristics which prevent or reduce the risk of flame penetration into the aeroplane after an accident and which ensure survivable conditions in the cabin for the time needed to evacuate the aeroplane.