Enviromental Control Systems Flashcards
What bleed air systems can be used to supply the air conditioning packs?
External air, APU air or bleed air from the engines, depending on the situation.
What is the maximum altitude for single A/C pack operation?
FL 310
What switch position allows conditioned air to cool the flight deck CRT displays
STDBY on the DISPLAY/AVIONICS fan control panel.
How are the avionics cooled?
Ambient underfloor air or by the avionics exhaust fan.
What happens if the CPC microprocessor fails?
The oxygen masks will not drop automatically and the Seatbelt and No Smoking signs will not illuminate.
If the cabin altitude reaches 14,000 feet, what will the CPAM do?
Trigger the oxygen system auto deploy and present the masks to the passengers
The “CABIN PRESSURE” aural warning will be heard when ______________________.
Cabin altitude exceeds 10,000 feet or the differential pressure exceeds 8.7 psid.
What does the flight abort mode of the pressurization system do?
Holds the departure airport elevation setting for 10 minutes after takeoff or 6000 feet above takeoff field elevation
Where does the air from the engines used for pneumatics come from?
From the 6th and 10th stage bleed sections of the N2 compressor.
What is the purpose of the check valve on the 6th stage bleed line?
Prevents back flow of 10th stage air into the engine when the High Pressure Bleed Valve (HPV) is open.
When does bleed air switching occur during landing
Flaps are greater than 20 degrees or the landing gear is down.
With the bleed valve control in the manual mode, it is possible to provide APU air to the Wing Ice protection system.
False–Wing bleed valves will close and BLEED MISCONFIG message will appear on EICAS..
What happens to the water extracted from the conditioned air produced by the A/C packs?
It is ducted back into the ram air flow to help cool the heat exchangers.
On the ground, air exhausted from the cooling displays and the avionics area exits the aircraft through________________.
The ground valve and is vented overboard through the bulkhead.
Two safety valves in the aft bulkhead serve to___________.
Protect against both over pressurization and negative pressure
If the automatic temperature control feature of an A/C pack malfunctions, what can the pilot do?
Select the MAN switchlight for that pack and control the temperature control valve with the HOT/COLD toggle switch.
How is the galley air heated?
By a 1000 watt electric heater, controlled by the HEATER switchlight at the galley control panel
What is the maximum positive and negative pressure differential?
Positive–8.7 psid
Negative -0.5 psid
What will happen if the active cabin pressure controller fails?
The standby controller will automatically take over control.
The EMER DEPRESS switch light will allow the outflow to open and the cabin will rise to ____________. It should not be selected at altitudes above __________.
14,500 feet/15,000 feet
How would select the other auto pressure controller in flight? How would you select the Manual controller?
Press the PRESS CONT switchlight twice to change active controllers. Press it once to select the manual controller.
What does an illuminated FAULT light on the CABIN PRESS panel indicate and what would you do?
Failure of both automatic pressure controllers has occurred. Pilot should take over with MAN control per the QRH.
A red CABIN ALT message indicates that the cabin altitude exceeds ____feet. An amber CABIN ALT message indicates the cabin altitude is____________________.
10,000/between 8,500 and 10,000 feet.
Cooling air for the air conditioning heat exchangers is provide by_________________.
the Ram Air Scoop
What is 10th stage bleed air used for?
Augment the bleed air supply when the 6th stage cannot meet demands
