There is a ventilation system which is installed in the landing gear bays in order to eliminate ozone and to cool the brakes and wheels. The nose landing gear ventilation system differs from that of the main gear ventilation system.
Nose Gear Bay Ventilation
The nose gear bay ventilation is associated with the operation of pressure regulating and safety valves. The ventilating air is bled from regulating and safety valve discharge nozzles by a duct at the end of which a venturi and a non-return valve are mounted. The venturi limits the airflow; the non-return valve prevents the air ventilating the nose gear bay from returning to the regulating and safety valve discharge nozzle.
The air is discharged from the nose gear bay by two discharge orifices Located on the landing gear bay longitudinal door (one orifice on each door).
A safety valve is installed on each forward regulating and safety valve discharge nozzle. In the event of a malfunction with the ground pressure relief valve, the air is discharged through safety valves. If overpressure occurs inside the nose gear bay, both safety valve flaps open and the excess air is discharged overboard.
Main Gear Bay Ventilation
The main gear bay is ventilated by air bled under cabin floor at a level of FR53. The air flows through a strainer to a Y duct. Each branch ducts the air respectively to the LH and RH main gear bays. In each gear bay the ventilation airflow is controlled by a venturi which is located at the air duct outlet. A non-return valve in each venturi prevents the air from the gear bays returning to the pressurized area.