Air Conditioning

Question 1

How many temperature zones?

Answer 1

7 - The flight deck & 6 pax zones

Question 2

The A/C System Supplies

Answer 2

Cabin & Cockpit

Forward, Aft, & bulk cargo Heat

Lav & Galley Ventilation

Gasper System

Shoulder & Foot Heater

Ventilation for lower crew rest & cockpit rest compartments

Question 3

The left trim air system supplies:

Answer 3

the cockpit

3 zone ducts & the aft cargo compartment

Question 4

The right trim air system supplies:

Answer 4

the other 3 zones ducts & the E & E bay.

Question 5

An external conditioned air source can supply conditioned air directly

Answer 5

into the air conditioning manifold.

Question 6

The flight deck receives 100 % fresh conditioned air, from the left pack and:

Answer 6

is at a slightly higher pressure to prevent smoke from entering.

Question 7

External High Pressure Hot Air may be:

Answer 7

used during ground operations to feed hot air directly into the bleed manifold.

Question 8

The Gasper system operates independently to the air conditioning system.

It supplies air from:

Answer 8

the aft distribution duct.

Question 9

Operation of the ram inlet and exhaust doors is by a predetermined schedule set by the pack temperature controllers

Answer 9

in the AUTO mode.

Question 10

The packs are capable of producing higher than normal air flow for air conditioning and pressurization under certain operating conditions. The high flow system is automatic

Answer 10

armed for operation at all times.

Question 11

During ground operation whenever the APU or ground source is supplying air for air conditioning both packs increase airflow. In flight if one pack or recirculation fan is off, or inoperative,

Answer 11

pack airflow is increased.

Question 12

Pack output is automatically limited during high bleed air demand periods such as

Answer 12

engine start or for gear retraction during take-off.

Question 13

Zone target temperatures are shown in magenta, while actual temperatures

Answer 13

in white.

Question 14

With the cabin temperature control in the auto position, and the trim air switches ON, the zone temperature controller provides automatic control for the system and uses feedback from various sensors to

Answer 14

determine the coldest zone requirement.

Question 15

Remember the cabin management temperature control can only operate within +/- 10 ° of the master set temperature

Answer 15

and cannot exceed 65 ° to 85 ° temperature range.

Question 16

selecting HIGH setting on the bulk cargo selector turns on the bulk ventilation fan,

Answer 16

which is provided for animal carriage.

Question 17

The lavatory / galley vent fans draw air across temperature sensors in each compartment.

Answer 17

If both fans fail, cargo heat is not provided.

Question 18

The EICAS advisory message CARGO HEAT AFT or BULK notifies the crew if a shutoff occurs or if a selector is off. Automatic overheat shutdowns prevent the related cargo heat

Answer 18

from being restored in flight.

Question 19

With equipment in override, cooling for flight deck panels and the E & E compartment is by reverse air flow created by cabin differential pressure, which is adequate in cruise

Answer 19

but decreases as the airplane descends.

Question 20

EQUIP. Cooling - Primary & Back up Fans

in AUTO

Answer 20

backup starts automatically if primary fails.

Question 21

Lower Crew Rest Compartment (LCRC) - 1

×

AIRFLOW OFF light and an AIRFLOW / SMOKE RESET switch

The AIRFLOW OFF light indicates the valve supplying air to the LCRC is commanded closed due to one of the following:

Answer 21

airplane altitude is less than 25,000 ft; main compartment hatch is closed; during smoke detection mode; or the airplane is on the ground and the left pack is on.

Question 22

The left ASCPC is considered the master and the right ASCPC the standby controller,

Answer 22

which will automatically take over, should the master fail.

Question 23

Air supply and cabin pressure controllers (ASCPC)

send cabin pressure data to the

Answer 23

Airplane Information Management System (AIMS) and from the remote pressure sensor through the Electrical Load Management System (ELMS).

Question 24

ASCPC in ground mode

Answer 24

commands the outflow valves fully open.

Question 25

Before take-off the pressurization controllers use FMC information to calculate a pressurization schedule

Answer 25

such as cruise altitude, time to climb, Top Of Descent point, time to descend, landing altitude and both ambient and cabin pressure.

Question 26

In Pack Standby mode:

Answer 26

With one pack inoperative and the other in standby cooling mode, or with both packs in standby cooling mode, the pack or packs operate continuously to maintain pressurization.

This happens regardless of altitude or Outside Air Temperature. Cabin and flight deck temperatures may be warmer at lower altitudes in this situation.

Question 27

Trim Air Advisory cause:

Answer 27

Trim valve failed closed

zone duct overheat

Question 28

Forward system automatically reconfigures to override mode when:

Answer 28

EQUIP COOLING switch is in OVRD

In flight both supply fans failll

Inflight low airflow is detected

smoke is detected in the forward equipment cooling system or the forward equipment ventilation system

The FWD CARGO FIRE ARM switch is ARMED

Question 29

In the automatic override mode and with the FWD CARGO FIRE ARM switch not armed,

Answer 29

supply fans are inoperative, the vent valve opens and the forward cargo heat valve closes.

Question 30

In the automatic override mode and with the FWD CARGO FIRE ARM switch ARMED

Answer 30

supply fans are inoperative, the vent valve and forward cargo heat valve close.

Question 31

Two fans are used to cool the aft equipment racks; the primary and backup fans. If the operating fan fails,

Answer 31

the backup fan starts automatically.

The fan draws conditioned air through the aft electronic equipment rack and then exhausts near the aft pressurization outflow valve. Lavatory units, galleys and cabin temperature sensor assemblies are also ventilated by the aft equipment cooling system.

Question 32

Should the cabin altitude climb to 8,500 ft EICAS

Answer 32

automatically displays the pressurization system indications. An amber 8,500 is shown.