02 - Air Systems

Question 1

AIR SYSTEMS
1. What are the sources of the Bleed Air System?

Answer 1

• Engines
• APU
• External pneumatic air

SH 2.010 p4-6

Question 2

AIR SYSTEMS
2. What is the purpose of the Air Supply Controller (ASC)?

Answer 2

Bleed regulation and Pack Flow/Temp Control by Control of the PRSOV and HPSOV. It digitally controls the output of 4th- and 10th-stage pneumatic air in response to bleed air demands.

SH 2.010 p4

Question 3

AIR SYSTEMS
3. What causes the engine bleed air valve to automatically close?

Answer 3

• High temp (254 degrees C)
  or
• Overpressure (170 psi for 5 sec)
• Engine start (on the engine being started)
• Start lever to cutoff

SH 2.010 p2-4

Question 4

AIR SYSTEMS
4. What does illumination of the BLEED light indicate?

Answer 4

• bleed sensor(s) have closed the associated engine bleed air valve for over-temperature (254 degrees C)
or excessive pressurization (170 psi for 5 sec MAX, 220 psi NG) 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 (MAX only)

SH 2.010 p4, 8

Question 5

AIR SYSTEMS
5. What causes the automatic closure of the APU bleed valve?

Answer 5

The APU being shutdown, regardless of switch position.

SH 2.010 p5

Question 6

AIR SYSTEMS
6. What is the position of the isolation valve with the ISOLATION VALVE switch in AUTO?

Answer 6

Closed - with both engine BLEED switches ON and both PACK switches in AUTO or HIGH;
Open - with any engine BLEED or PACK switch in the OFF position

SH 2.010 p7

Question 7

AIR SYSTEMS
7. What does the illumination of the DUAL BLEED light indicate?

Answer 7

two sources of bleed air (engine & APU) could be pressurizing the left bleed duct (Thrust must be limited to idle). This happens during SET due to the APU bleed air valve being open & Engine 1 Bleed Switch ON. Also when the APU bleed air valve open, Engine 2 Bleed Switch is ON, & the isolation valve is open

NOTE: The DUAL BLEED light monitors engine BLEED switch position and APU bleed valve position

SH 2.010 p8

Question 8

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

Answer 8

Max certified ceiling of 41,000’

SH 2.020 p3

Question 9

AIR SYSTEMS
9. What causes a pack to automatically switch to high airflow?

Answer 9

With pack switch in AUTO;

• Failure of a pack or an engine with;
  
  • aircraft airborne
  • Flaps UP
  • Both engine bleed switches ON
• Pack switch OFF in flight with Flaps UP (remaining PACK)
• EQUIP SMOKE light illuminated (both PACKS)

SH 2.020 p3

Question 10

AIR SYSTEMS
10. How many controllers does each pack have?

Answer 10

Each pack has one dual-channel pack/zone electronic controller. Digital channel is primary and analogue channel provided back up control for opposite side pack automatically.

SH 2.020 p4

Question 11

AIR SYSTEMS
11. What does the illumination of the PACK light indicate?

Answer 11

• pack overheat
• failure of the pack valve to open when commanded
• failure of both the primary and standby pack controls for the same pack
• incorrect pack switch configuration after takeoff

SH 2.020 p6

Question 12

AIR SYSTEMS
12. Do the Flight Attendants have any control of cabin temperature?

Answer 12

Yes, but only on the MAX. The temperature set points for the forward and aft cabin zones can be adjusted +/- 3 degrees from the Flight Attendant panel

SH 2.020 p9

Question 13

AIR SYSTEMS
13. How is the failure of either the primary or standby pack controller indicated on the
ground?

Answer 13

The MAINT light and the OVERHEAD System Annunciator and MASTER CAUTION lights will illuminate after landing

SH 2.020 p6

Question 14

AIR SYSTEMS
14. What provides cooling air for the pack systems?

Answer 14

The Ram Air System, controlled by a Smart Ram Air Door Actuator (SRADA)

SH 2.020 p7

Question 15

AIR SYSTEMS
15. How is a supply duct overheat indicated?

Answer 15

ZONE TEMP lights

SH 2.020 p10

Question 16

AIR SYSTEMS
16. What is the primary source of conditioned air for the Flight Deck?

Answer 16

Directly from the left pack

SH 2.020 p12

Question 17

AIR SYSTEMS
17. What is the purpose of the recirculation fans?

Answer 17

Reduce Engine Bleed Air and Pack System demand and increase engine efficiency

SH 2.020 p14

Question 18

AIR SYSTEMS
18. Can pre-conditioned air temperature be controlled by the packs?

Answer 18

No, only at the external air source

SH 2.020 p14

Question 19

AIR SYSTEMS
19. What does the Equipment Cooling System cool?

Answer 19

electronic equipment in the Flight Deck and E&E Bay

SH 2.020 p15

Question 20

AIR SYSTEMS
20. Which cargo compartment is heated by warm air from the Equipment Cooling System’s exhaust fans?

Answer 20

FWD

SH 2.020 p15

Question 21

AIR SYSTEMS
21. What does the EQUIP COOLING OFF light indicate?

Answer 21

Loss of airflow due to the failure of a fan

SH 2.020 p15

Question 22

AIR SYSTEMS
22. What does the illumination of the EQUIP SMOKE light indicate?

Answer 22

Smoke is detected downstream of the fans

SH 2.020 p16

Question 23

AIR SYSTEMS
23. How is the alternate pressurization controller selected?

Answer 23

Selecting ALTN on the Cabin Pressurization Panel

SH 2.030 p2

Question 24

AIR SYSTEMS
24. How are pressurization controller failures indicated?

Answer 24

• AUTO FAIL light and ALTN light for a single-channel failure
• Only AUTO FAIL light for dual cabin pressurization controller failure. FLT ALT and LAND ALT windows display dashes

SH 2.030 p9

Question 25

**AIR SYSTEMS** 25. What would cause the OFF SCHED DESCENT light to illuminate?

Answer 25

A descent beginning prior to the aircraft reaching the set FLT ALT (e.g., an air turn-back during climb). The **AIR COND** System Annunciator and **MASTER CAUTION** lights also illuminate. *SH 2.030 p8*

Question 26

**AIR SYSTEMS** 26. The CABIN ALTITUDE light and altitude warning horn activate at approximately what altitude?

Answer 26

10,000’ +/- 1,000’ *SH 2.030 p10*

Question 27

**AIR SYSTEMS** 27. Can the cabin altitude warning horn can be silenced using the ALT HORN CUTOUT switch above 10,000 ft?

Answer 27

**Yes** *SH 2.030 p10*

Question 28

**AIR SYSTEMS** *EXTRA CREDIT* What is indicated by these two lights on the Cabin Pressurization Panel?

Answer 28

Failure of **one** of two identical CPCs. Pressurization control automatically transfers to the other controller. The 2 CPCs normally alternate every flight. *SH 2.030 p9*

Question 29

**AIR SYSTEMS** *EXTRA CREDIT* What does this indicate?

Answer 29

A failure of **both** CPCs *SH 2.030 p9*

Question 30

**AIR SYSTEMS** *EXTRA CREDIT* What occurrences will cause the illumination of the AUTO FAIL light on the Cabin Pressurization Panel?

Answer 30

- Loss of DC power - Outflow valve controller fault - CPC fault - Excessive differential pressure (>8.75 psi) - Excessive rate of cabin pressure change (+2,000 fpm) - High Cabin altitude (>15,800 ft) *SH 2.030 p9*

Question 31

**AIR SYSTEMS** *EXTRA CREDIT* What will cause this light to illuminate?

Answer 31

An **overheat** has been detected due to a **bleed air duct leak** *SH 2.010 p9*

Question 32

**AIR SYSTEMS** *EXTRA CREDIT* What stage(s) bleed air does the MAX pneumatic system use?

Answer 32

**4th** and **10th** *SH 2.010 p4*

Question 33

**AIR SYSTEMS** *EXTRA CREDIT* What 3 conditions/lights may the trip reset button be used for?

Answer 33

- ZONE TEMP - PACK - BLEED *SH 2.010 p8*

Question 34

**AIR SYSTEMS** *EXTRA CREDIT* ***NG Differences*** What stage(s) bleed air does the CFM 56 use on the NG?

Answer 34

**5th** and **9th** stages *SH 2.010 p8*