AVIONICS COOLING, EXTRACTION AND SMOKE PATHS
Cabin comfort and avionics cooling are related environmental services but distinct control problems. Avionics equipment produces heat even when the cabin feels comfortable. The historical Airbus architecture uses an avionics ventilation controller, blower and extract fans, valves and an aircraft-skin heat exchanger. The selected path changes with the operating condition. This explains why an apparently quiet cockpit can still require a functioning cooling path for electronics and why a temperature problem may be associated with ventilation configuration rather than the cabin selector alone. [87, PDF p. 163]
The briefing distinguishes open, closed and intermediate arrangements. In an open arrangement outside air provides cooling; a closed arrangement uses a heat-exchange path through the aircraft skin; another condition changes the extraction/bypass arrangement. These are architecture descriptions from an identified historical source, not a current Fenix valve-timing specification. The crew-facing task is to recognise a ventilation warning, relevant configuration and affected equipment. Do not infer the exact position of every cooling valve merely from fan noise or cockpit temperature. [87, PDF p. 163]
Ventilation also affects where smoke is detected and how it is distributed. A smoke indication in the avionics path identifies detection in that path; it does not automatically identify the first failed component or establish a cargo-compartment fire. The aircraft’s smoke/fumes procedure exists because source identification, breathing protection and ventilation changes interact. Retain the distinction between detection, isolation and extraction. A maintenance test or arbitrary fan-switch experiment can change evidence and air routing without establishing that the initiating condition has been removed. [78, PDF p. 2] [88, ECAM philosophy; identification, actions and resulting status]
The briefing separately describes battery ventilation and lavatory/galley extraction. Their purposes differ from conditioned-air delivery to occupants. A failed extraction fan can therefore belong to a local ventilation function even though pack temperature control remains available. For a Fenix scenario, establish the implemented failure and displayed consequence before extending this real-aircraft dependency into a claim about every cabin fan. The coverage matrix deliberately leaves detailed cooling-valve failure behaviour unverified where the public implementation documentation does not define it. [87, PDF p. 163] [86, Failure-management documentation; implemented-scenario scope]