200 environmental controls Flashcards
What stage of the engine to the packs get air from?
The 10th stage
Where are the air conditioning units located
In the aft equipment bay
Where is the air distributed that comes from the left and right pack?
The left pack will normally supply the cockpit and the right pack will supply the cabin
What regulates the pressure of the air from the tenth stage before it enters the pack?
Due to extreme pressure of the Air from the 10th stage, the air could damage the pack if the pressure was not reduced. This is the job of the pack pressure regulating shut off valve “PRSOV” and his used to reduce the pressure of the air before it enters the pack.
What would occur if the PRSOV failed
The valve would Close, the pack would shut down and a pack high-pressure EICAS message would be displayed.
How does the PRSOV help a single pack supply sufficient pressure to the flight deck in the cabin during single pack operations?
There are two pressure settings, one for dual pack and one for single pack. When two packs are available, the PRSOVs reduce the 10th stage pressure to a normal pressure. During single pack operations the single PRSOV Will increase the operating pressure, which will permit the single pack to supply the cabin and flight deck with sufficient airflow. It will not be at the same volume as with both packs operating.
What is the single pack operating altitude limit?
25,000 feet
What cools the hot air for the air-conditioning system?
An air cycle machine and heat exchangers coolS THE hot compressed air.
What is the purpose of the ram air scoop at the base of the vertical stabilizer?
Air enters this scoop and is used as the cooling means for the air to air in heat exchangers. The ram air flows across the pre-cooler and dual heat exchangers thus cooling the pack air. The cooling ram air exits through the events located at the lower right and left sides of the fuselage in the aft area. When the aircraft is on the ground there is no ram air to enter the scoop so I fan that is driven by the air cycle machine draws the air in the scoop.
What are the sources of air conditioning bleed air?
APU
Engines
External air cart
What is the altitude limit for extracting bleed air from the APU for air conditioning? What will happen if the APU is used for bleed air above this altitude?
The limit is 15,000 feet. If this altitude is exceeded the EICAS caution message APU BLEED AIR ON Will appear.
Where is the left pack air distributed?
The air will be sent to the flight deck gaspers, vents and side console outlets. It will also be used for EICAS and EFIS Display cooling.
Where is the right pack air distributed?
It is distributed to the floor outlets in the passenger cabin, laboratory, galley, and the gaspers on the PSU’s
Where is the cabin air exhausted?
The air is sent under the floor to outflow valves on the aft pressure bulkhead.
Where is the low pressure ground air connection?
It Is located behind the wing on the right side of the aircraft.
Does the low pressure air cart supply air to the PACks for the aircraft cooling?
No, the air is sent directly to the distribution manifold, which then travels to all the outlets
What must be done before the low pressure air can be turned on?
The main cabin door or avionics bay door must be open.
Explain how suitable airflow is maintained in the cargo bay.
A fan draws recirculated passenger cabin exhaust air from under the floor into the cargo bay to maintain suitable airflow and temperature.
In addition to the recirculated air, there’s an optional automatic temperature control that uses right fresh pack air for cooling and an electric heater for increasing temperature. This controller maintains a the cargo bay that is better suited for live animals.