Air Conditioning Flashcards
The APU provides bleed air in flight up to what altitude?
20,000’
What decreases the temperature of the air as it leaves the engines?
A precooler in the aft equipment compartment
The L BLEED and R BLEED control what valves?
The IP pressure valves off the engines
The AIR SOURCE knob controls what valves?
The flow control valves that allow air through the PACK and TRIM AIR section
During an engine start, the flow control valves close for what reason?
To ensure that the air turbine starters receive sufficient airflow for starter operation
Ram air enters the aircraft where?
Base of the aircraft vertical fin
Where is the ram air exhausted?
Left side of aircraft just behind the left engine
The precooler limits the PACK inlet and TRIM air inlet to what temperature?
220 C
Below what altitude can the RAM AIR switch be selected to ON in the event that pack air and trim air fail?
10,000’ to ventilate the cockpit and cabin
What ensures overall air conditioning system control and monitoring?
Two IASC’s
Where are the IASC’s located?
One unit is under the floor and the other is under the liner of the lavatory above the floor.
Each IASC consists of two channels that monitor what?
Channel A for air conditioning control and monitoring, avionics cooling, and cabin pressurization.
Channel B for wing anti-icing monitoring and control, bleed leak detection and monitoring, and limited back-up control for the air condition system
Where is the backup cabin pressure sensor located?
IASC 1 Channel B
What is the temperature range in the automatic mode?
15 to 35C
Where are the sensors located for the automatic mode?
In the passenger cabin and cockpit
What is the temperature in the manual range?
3 to 70C
Where are the sensors located for the manual mode?
In the ducts downstream of the hot air injectors
On the ground, ram air is virtually nonexistent in helping to cool the heat exchangers. What aids in supplying adequate air for cooling?
A fan in the ram air duct which is driven by the ACM. The fan creates a suction effect to draw in adequate air.
Cold air only is provided into the cabin and cockpit though …
The overhead gaspers
The battery compartment is heated how?
Holes in the cabin sill allow cabin air to travel under the floor to ventilate and heat the compartment
How are the avionics racks and cockpit displays cooled?
A fan under the cockpit floor and an avionics cooling valve. Either can draw air from behind the displays or from above the avionics racks
What normally controls and monitors the ventilation(exhaust of cockpit/cabin air).
IASC 1. If a failure occurs with IASC 1, IASC 2 takes over in a degraded mode.
During ground operations, the avionics fan operates at what speed?
High
In flight, the avionics fan operates at what speed?
Low
In flight, at what temperature in the avionics racks causes the fan to go to High?
50 C in a 60 second time period
What occurs if the temperature rises above 65 C in the avionics rack during a 60 second time period above 10,000’?
The fan is turned off and the IASC opens the avionics valve
