Air Systems

Question 1

What are the sources of the air in the Bleed Air System?

(SM)

Answer 1

Engines, APU, External Source

Question 2

What is the purpose of the Air Supply Controller?

(SM)

Answer 2

Bleed Regulation

(Pack Flow Temperature Control for temperature control of pack output)

Question 3

What causes the engine bleed air valve to automatically close?

(SM)

Answer 3

Overtemp or overpressure

Question 4

What does the illumination of the BLEED light indicate?

(SM)

Answer 4

Closure of the engine bleed valve due to over temperature or excessive pressurization of the bleed duct.

OR

A failure within the Bleed Air System that may not be resettable.

OR

An incorrect bleed configuration after takeoff or go-around.

Question 5

If the BLEED light illuminates after takeoff or a go-around, what is the likely condition?

(EXTRA)

Answer 5

Occurs 45 seconds after flaps reach the UP position if both BLEED switches are OFF. This feature is inhibited 10 minutes after the flaps reach UP to prevent nuisance messages in the event of a zero flap landing.

Question 6

What causes the automatic closure of the APU bleed valve?

(SM)

Answer 6

Shutting the APU down.

(Overpressure is protected by a relief valve.)

Question 7

What is the position of the isolation valve with the ISOLATION VALVE switch in AUTO?

(SM)

Answer 7

Both BLEED and PACK in AUTO or HIGH = Valve closed.

Any BLEED or PACK switch to OFF = Open

Question 8

What does illumination of the DUAL BLEED light indicate?

(SM)

Answer 8

2 sources of bleed air are pressurizing the left bleed duct.

Question 9

In the event of a single pack failure at altitude, the remaining pack is capable of maintaining cabin pressure and pressure up to what altitude?

(SM)

Answer 9

Max certified ceiling. (FL410)

Question 10

What causes a pack to automatically switch to high airflow?

(SM)

Answer 10

Aircraft is:
Airborne
Flaps UP
Both BLEED switches ON

Question 11

How many controllers does each pack have?

(SM)

Answer 11

Each have a dual channel electronic controller with a digital primary channel and an analog backup channel. The primary controls the respective pack and the analog controls the opposite side pack.

Question 12

What does the illumination of the PACK light indicate?

(SM)

Answer 12

• Failure of both primary and standby controls for the same pack. In this case the pack will continue to operate uncontrolled unless tripped off by excessive temperature or….
• Failure of the pack valve to open when it is commanded OR
• an incorrect PACK switch configuration after takeoff (both PACK switches in off 45 seconds after flaps are retracted), OR
• a pack overheat.

Question 13

Do the FA’s have any control of the cabin temperature?

(SM)

Answer 13

Yes, +/- 3 degrees from flight attendant panel.

Question 14

How is the failure of either the primary or standby pack controller indicated on the ground?

(SM)

Answer 14

MAINT light illuminates after landing.

Question 15

3 ZONE TEMP lights with a AIR COND annunciator indicate?

Answer 15

Both the right and left IASC (integrated Air Supply Computer) have failed.(MAX)

Question 16

What provides cooling for the pack systems?

(SM)

Answer 16

Ram Air System

Question 17

How is a supply duct overheat indicated?

(SM)

Answer 17

ZONE TEMP lights indicate a supply duct overheat of the associated zone, or failure of the left and right IASC.

Question 18

What is the primary source of conditioned air on the flight deck?

(SM)

Answer 18

Left Pack.

Question 19

What is the purpose of the recirculation fans?

(SM)

Answer 19

Reduce load on Engine Bleed and Pack system demands, increasing engine efficiency.

Question 20

Can preconditioned air temperature be controlled by the packs?

(SM)

Answer 20

No, the packs should be in the OFF position and the air enters the system at the mix manifold.

Question 21

What does the Equipment Cooling System cool?

(SM)

Answer 21

The E&E bay as well as the avionics.

FACTIOD: The exhaust is vented overboard via the OEV valve (heard during preflight near the O2 blowout disc) on the ground and is normally closed during flight. In flight with the OEV closed the exhaust provides heat to the forward cargo via the lining of that bay.

The OEV is determined by differential pressure.

On ground and with low differential pressure = open, air is exhausted overboard.

In flight with normal differentials = OEV is closed, air goes to FWD cargo lining.

Question 22

Which cargo compartment is heated by warm air from the Equipment Cooling System exhaust fans?

(SM)

Answer 22

FWD Cargo

Question 23

What does the EQUIPMENT COOLING OFF light indicate?

(SM)

Answer 23

Failure of the fan and loss of airflow. There is an alternate fan, which should reset the OFF light within 5 minutes.

(Failure on the ground sets off the crew call horn in the nose well)

Question 24

FACTOID: Will you get an EQUIPMENT COOLING “OFF” light if there is a forward cargo fire warning?

Answer 24

No, despite the cooling exhaust fan being shut off, the light is inhibited in this scenario.

Question 25

What does illumination of the EQUIP SMOKE light indicate? (Along with the MASTER CAUTION) (SM)

Answer 25

Two smoke detectors downstream of the fans have detected smoke. System automatically should: - packs set to high - E&E cooling supply off for ~5 minutes - Overboard Exhaust Valve to smoke position to vent overboard. - Recirc fans off After 5 mins: E&E resets to normal operations unless smoke is still detected. In which the supply fan will turn off. The OFF light for the supply fan will not illuminate during this automatic shutoff.

Question 26

How is the alternate pressurization controller selected? (SM)

Answer 26

Select the pressurization mode selector to MAN, which controls a DC powered manual motor. (Then the valve is controlled with the CLOSE OPEN switch above)

Question 27

How are pressurization controller failures indicated? (SM)

Answer 27

**AUTO FAIL illuminates when:** * Loss of DC power, OR * Outflow Valve Control fault, OR * Cabin pressurization controller fault. **If the controller is not responding properly, then the AUTO FAIL light will also be illuminated when:** * Excessive differential pressure (>8.75psi) * Excessive rate of pressure change (=/- 2000 fpm) * High Cabin Altitude (>15,000) In these cases the control transfers to the alternate controller and a green ALTN light illuminates. Moving the switch to ALTN will extinguish the AUTO FAIL but the green ALTN will stay illuminated.

Question 28

What would cause the OFF SCHED DESCENT light? (SM)

Answer 28

Descent begins prior to reaching the FLT ALT set in the controller. (Air turn back). The system programs the cabin to descent to the airport elevation if nothing is changed. (Set the altitude to the desired altitude or set the LAND ALT to the desired field elevation.)

Question 29

The red CABIN ALTITUDE light and altitude warning horn activate at approximately what altitude? (SM)

Answer 29

Cabin altitude exceeds 10,000 +/- 1,000

Question 30

Can the cabin altitude warning horn be silenced using the ALT HORN CUTOUT switch above 10,000 feet? (SM)

Answer 30

Yes (CABIN ALTITUDE lights will stay illuminated until condition no longer exists)