"Skin Air Inlet Valve Replacement"

After T/S was necessary do a replacement of the skin air valve.

Ventilation of the avionics is primarily provided by two fans, one acting as a blower, the other as an extractor.

Control is provided by the Avionics Equipment Ventilation Computer (AEVC).

The system's normal modes are:

1.Close-circuit: Used when skin temperature is low. Air being drawn from the avionics bay and exhausted into the underfloor of the cargo bay, with a return loop via the skin heat exchanger.

2.Intermediate: Used in flight when skin temperature is high. This is similar to close-circuit except the skin air extract valve is partially opened to allow some air to exhaust overboard.

3.Open-circuit: Used for ground operations with a high skin temperature. Air from outside the aircraft is moved across the avionics equipment and then exhausted externally.

The skin temperature thresholds are different for flight and ground cases and incorporate a dead band to prevent rapid mode switching.

The bands are 9°C to 12°C on the ground and 32°C to 35°C in flight.

✈️ Airbus A320 | Engine CFM56-5B

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