Enviromental Control Systems

Question 1

What bleed air systems can be used to supply the air conditioning packs?

Answer 1

External air, APU air or bleed air from the engines, depending on the situation.

Question 2

What is the maximum altitude for single A/C pack operation?

Answer 2

FL 310

Question 3

What switch position allows conditioned air to cool the flight deck CRT displays

Answer 3

STDBY on the DISPLAY/AVIONICS fan control panel.

Question 4

How are the avionics cooled?

Answer 4

Ambient underfloor air or by the avionics exhaust fan.

Question 5

What happens if the CPC microprocessor fails?

Answer 5

The oxygen masks will not drop automatically and the Seatbelt and No Smoking signs will not illuminate.

Question 6

If the cabin altitude reaches 14,000 feet, what will the CPAM do?

Answer 6

Trigger the oxygen system auto deploy and present the masks to the passengers

Question 7

The “CABIN PRESSURE” aural warning will be heard when ______________________.

Answer 7

Cabin altitude exceeds 10,000 feet or the differential pressure exceeds 8.7 psid.

Question 8

What does the flight abort mode of the pressurization system do?

Answer 8

Holds the departure airport elevation setting for 10 minutes after takeoff or 6000 feet above takeoff field elevation

Question 9

Where does the air from the engines used for pneumatics come from?

Answer 9

From the 6th and 10th stage bleed sections of the N2 compressor.

Question 10

What is the purpose of the check valve on the 6th stage bleed line?

Answer 10

Prevents back flow of 10th stage air into the engine when the High Pressure Bleed Valve (HPV) is open.

Question 11

When does bleed air switching occur during landing

Answer 11

Flaps are greater than 20 degrees or the landing gear is down.

Question 12

With the bleed valve control in the manual mode, it is possible to provide APU air to the Wing Ice protection system.

Answer 12

False–Wing bleed valves will close and BLEED MISCONFIG message will appear on EICAS..

Question 13

What happens to the water extracted from the conditioned air produced by the A/C packs?

Answer 13

It is ducted back into the ram air flow to help cool the heat exchangers.

Question 14

On the ground, air exhausted from the cooling displays and the avionics area exits the aircraft through________________.

Answer 14

The ground valve and is vented overboard through the bulkhead.

Question 15

Two safety valves in the aft bulkhead serve to___________.

Answer 15

Protect against both over pressurization and negative pressure

Question 16

If the automatic temperature control feature of an A/C pack malfunctions, what can the pilot do?

Answer 16

Select the MAN switchlight for that pack and control the temperature control valve with the HOT/COLD toggle switch.

Question 17

How is the galley air heated?

Answer 17

By a 1000 watt electric heater, controlled by the HEATER switchlight at the galley control panel

Question 18

What is the maximum positive and negative pressure differential?

Answer 18

Positive–8.7 psid

Negative -0.5 psid

Question 19

What will happen if the active cabin pressure controller fails?

Answer 19

The standby controller will automatically take over control.

Question 20

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 __________.

Answer 20

14,500 feet/15,000 feet

Question 21

How would select the other auto pressure controller in flight? How would you select the Manual controller?

Answer 21

Press the PRESS CONT switchlight twice to change active controllers. Press it once to select the manual controller.

Question 22

What does an illuminated FAULT light on the CABIN PRESS panel indicate and what would you do?

Answer 22

Failure of both automatic pressure controllers has occurred. Pilot should take over with MAN control per the QRH.

Question 23

A red CABIN ALT message indicates that the cabin altitude exceeds ____feet. An amber CABIN ALT message indicates the cabin altitude is____________________.

Answer 23

10,000/between 8,500 and 10,000 feet.

Question 24

Cooling air for the air conditioning heat exchangers is provide by_________________.

Answer 24

the Ram Air Scoop

Question 25

What is 10th stage bleed air used for?

Answer 25

Augment the bleed air supply when the 6th stage cannot meet demands