Recirculation Fan (Contd.)
In flight, the left recirculation fan operates if both packs are operating unless
either PACK switch is in HIGH. The right recirculation fan operates in flight if both
packs are operating unless both PACK switches are in HIGH. On the ground, the
left recirculation fan operates unless both PACK switches are in HIGH and the
right recirculation fan operates even if both PACK switches are in HIGH.
Equipment Cooling
The equipment cooling system cools electronic equipment in the flight deck and
the E & E bay. The equipment cooling system consists of a supply duct and an
exhaust duct. Each duct has a normal fan and an alternate fan. The supply duct
supplies cool air to the flight deck displays and electronic equipment in the E & E
bay. The exhaust duct collects and discards warm air from the flight deck
displays, the overhead and aft electronic panels, circuit breaker panels in the
flight deck, and electronic equipment in the E & E bay. Loss of airflow due to
failure of an equipment cooling fan results in illumination of the related equipment
cooling OFF light. Selecting the alternate fan should restore airflow and
extinguish the OFF light within approximately 5 seconds. If an overtemperature
occurs on the ground, alerting is provided through the crew call horn in the nose
wheel well.
Forward Cargo Compartment
The recirculation fan system circulates air from the passenger cabin around the
lining of the forward cargo compartment. When the overboard exhaust valve is
closed, exhaust air from the equipment cooling system is also diffused to the lining
of the forward cargo compartment for additional inflight heating.
Conditioned Air Source Connection
A ground air conditioning source may be connected to the mix manifold to
distribute preconditioned air throughout the airplane.
In flight, the left recirculation fan operates if both packs are operating unless
either PACK switch is in HIGH. The right recirculation fan operates in flight if both
packs are operating unless both PACK switches are in HIGH. On the ground, the
left recirculation fan operates unless both PACK switches are in HIGH and the
right recirculation fan operates even if both PACK switches are in HIGH.
Equipment Cooling
The equipment cooling system cools electronic equipment in the flight deck and
the E & E bay. The equipment cooling system consists of a supply duct and an
exhaust duct. Each duct has a normal fan and an alternate fan. The supply duct
supplies cool air to the flight deck displays and electronic equipment in the E & E
bay. The exhaust duct collects and discards warm air from the flight deck
displays, the overhead and aft electronic panels, circuit breaker panels in the
flight deck, and electronic equipment in the E & E bay. Loss of airflow due to
failure of an equipment cooling fan results in illumination of the related equipment
cooling OFF light. Selecting the alternate fan should restore airflow and
extinguish the OFF light within approximately 5 seconds. If an overtemperature
occurs on the ground, alerting is provided through the crew call horn in the nose
wheel well.
Forward Cargo Compartment
The recirculation fan system circulates air from the passenger cabin around the
lining of the forward cargo compartment. When the overboard exhaust valve is
closed, exhaust air from the equipment cooling system is also diffused to the lining
of the forward cargo compartment for additional inflight heating.
Conditioned Air Source Connection
A ground air conditioning source may be connected to the mix manifold to
distribute preconditioned air throughout the airplane.
