ATA 21 AC

Question 1

The MAX has ____ air-conditioned zones, what are they called?

Answer 1

3: Flight Deck
FWD Cabin
AFT Cabin

Question 2

What is the purpose of the Air Conditioning Accessory Units?

Answer 2

Provide the discrete outputs that enable or disable operation of the cooling pack and the temperature control system components.

Question 3

What are the air conditioning accessory units for?

Answer 3

They’re the interface for the airplane operational logic and the air system

Question 4

Describe where the air output from each air conditioning pack goes.

Answer 4

The left cooling pack goes to the flight compartment zone, then air from the right cooling pack goes to the passenger cabin area.

Question 5

How are lavatory and galleys ventilated?

Answer 5

There’s an air intake that draws into a central muffler and manifold that lets air out

Question 6

How do you get the alternate equipment cooling exhaust fan to operate?

Answer 6

Supply equipment cooling fan switch is in the ALTERNATE position and the same logic conditions as the normal fan.

Question 7

Describe the conditions required to put the equipment cooling system into smoke
clearance mode of operation.

Answer 7

L PACK or R PACK switch: HIGH
R RECIRC Fan switch: OFF

Question 8

Describe how to operate the outflow valve manually.

Answer 8

Using the control module toggle switch

Question 9

How is failure of one cabin pressure controller indicated?

Answer 9

MDS and **BITE check on front face of Cabin Pressure Controller in E and E bay

Question 10

Pressurization system BITE is performed using the __________.

Answer 10

System configuration.

Question 11

How is heat provided for the forward and aft cargo pits?

Answer 11

Equipment cooling exhaust and passenger compartment air

Question 12

Will the door area heaters operate on the ground?

Answer 12

???

Question 13

What controls the ram air exit door actuator?

Answer 13

Smart Ram Air Door Actuators (SRADA)

Question 14

What does the Integrated Air Systems Controller control? (in the air conditioning
system)

Answer 14

Pack Cooling Temperature
Trim air, regulation, on or off
Zone Temperature

Question 15

What does the P5 forward overhead panel let you control with regards to the AC system?

Answer 15

Cabin Temperature panel P5-17, Air Conditioning/bleed air control panel P5-10.

Question 16

What does the zone trim air modulating valve control?

Answer 16

Controls the heat added to the conditioned air for each zone.

Question 17

What cooling pack does the flight compartment utilize?

Answer 17

Left

Question 18

What does the standby temperature control valve do?

Answer 18

**Increases the temperature of pack discharge air to prevent ice formation in the condenser*
Gives backup control for the discharge temperature of the air conditioning pack(normal temperature control failure).

Question 19

How many trim air valves

Answer 19

4

Question 20

How many ISAC’s?

Answer 20

2

Question 21

If everything goes sideways what’s the temperature that the system will default too?

Answer 21

75 degrees F (24 degrees C)

Question 22

When does the Pack light turn on?

Answer 22

Overtemperature conditions and failures of the AC temperature control system

Question 23

Where does logic for the door area heaters come from?

Answer 23

From the air/ground system and air conditioning pack valve operation

Question 24

How many motors does the outflow valve have?

Answer 24

3 DC Motors. 2 28DC and 1 48DC

Question 25

What do the cabin altitude warning switch’s do?

Answer 25

Warn the flight crew when the cabin altitude is critical.

Question 26

How many cabin altitude switch’s are there?

Answer 26

2. (S128 and S1153)

Question 27

What does it mean if the ZONE TEMP light comes on?

Answer 27

Overheat in a specific Zone