Text in force at CS27-10: from CS27-0, effective 14 Nov 2003.
Each part of the structure, controls, rotor mechanism, and other parts essential to a controlled landing that would be affected by powerplant fires must be fireproof or protected so they can perform their essential functions for at least 5 minutes under any foreseeable powerplant fire conditions.
ED Decision 2003/015/RM · Source