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CS 25.1103 Air intake system ducts and air duct systems

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

IRImplementing rule

CS 25.1103Air intake system ducts and air duct systems

(See AMC 25.1103)

(a)Reserved.

(b)Each air intake system must be –

(1)Strong enough to prevent structural failure resulting from engine surging; and

(2)Fire-resistant if it is in any fire zone for which a fire extinguishing system is required.

(c)Each duct connected to components between which relative motion could exist must have means for flexibility.

(d)For bleed air systems no hazard may result if a duct rupture or failure occurs at any point between the engine port and the aeroplane unit served by the bleed air. (See AMC 25.1103(d).)

[Amdt 25/18]

IR · CS 25.1103 — CS-25 · ED Decision 2016/010/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

AMCAcceptable means of compliance

AMC 25.1103(d)Air intake system ducts

Show the text

For a single failure case leading to a fire and air duct rupture, consideration should be given to the possibility of fire aggravation due to air flowing into a designated fire zone of an engine from the remaining engine(s), or another source outside the affected fire zone.

AMC · AMC 25.1103(d) — CS-25 · ED Decision 2003/2/RM · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

All rules in SUBPART E – POWERPLANT

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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