AIR Systems

Question 1

How is the Equpment cooling OVERRIDE mode configured when the LWR FWD CARGO FIRE ARM switch in NOT ARMED?

Answer 1

the vent valve opens, both supply fans shut down, and the lower forward cargo heat valve closes

Question 2

How is the equipment cooling OVERRIDE mode configured when the LWR FWD CARGO FIRE ARM switch IS ARMED?

Answer 2

the vent valve remains closed, both supply fans remain shut down, and the lower forward cargo heat valve is closed.

Cabin differential pressure draws air through the flight deck panels and into the E & E equipment compartment to create a reverse flow of air across the equipment, then through the override valve to an overboard vent.

Question 3

When will the E/E cooling system automatically config to OVERRIDE mode?

Answer 3

In flight both supply fans fail
In flight, low airflow is detected
Smoke is detected in the forward equipment cooling system or the forward equipment ventilation system

The LWR AFT CARGO FIRE ARM switch is ARMED, or
The LWR FWD CARGO FIRE ARM switch is ARMED
The EQUIP COOLING switch is in OVRD

Question 4

How is the equipment cooling system configured when the MAIN DECK FIRE switch is ARMED?

Answer 4

the system is configured to supply conditioned air to the flight deck and the air is exhausted through the
ventilation system into the lower forward cargo compartment

Question 5

In flight, the EQUIP COOLING switch in OVRD helps with what potential flight deck emergency?

Answer 5

Smoke in the flight deck

Question 6

In cabin altitude controller cruise mode, what is the max cabin altitude?

Answer 6

8,000ft

Question 7

When the takeoff field elevation is higher the 8,000ft, the cabin will do what while the aircraft is climbing?

Answer 7

The cabin will descend to the cabin cruise altitude while the airplane is climbing.

Question 8

In flight the cabin altitude controller operates in what three modes?

Answer 8

Climb mode
Cruise mode
Descent mode

Question 9

Where does the pressurization controller get its information?

Answer 9

Flight plan data from the FMC and

Ambient pressure

Question 10

At what cabin altitude will the altitude limiter close both outflow valves?

Answer 10

15,000ft

Question 11

When does the cabin altitude controller enter the descent mode?

Answer 11

At T//D or 1,000ft from cruise altitude

Question 12

What does the Alternate ventilation system do?

Answer 12

The alternate ventilation system provides air flow into the flight deck and supernumerary cabin when both air conditioning packs are inoperative

Question 13

How does the ALTN VENT work when pressurization is normal? And when pressurization is not normal?

Answer 13

In a normal pressurization situation there is no air flow through the alternate ventilation system.

If the airplane is not pressurized normally and the ALTN VENT switch is ON, air is drawn from the aft outflow valve and provided to the flight deck and supernumerary cabin

Question 14

The ENG bleed OFF light illuminates when?

Answer 14

OFF illuminated (amber) – the engine bleed valve is closed. The engine bleed valve is commanded closed and the OFF light is illuminated when:
• the engine is not running, or
• a bleed air overheat, overpressure, or bleed control system failure has occurred, or
• the valve is failed closed, or
• the L ENG bleed valve is closed during APU to Pack Takeoff procedure, or
• the ENG fire switch is pulled out, or
• the switch is off

Question 15

APU bleed switch, in AUTO indicates what?

Answer 15

AUTO – the APU bleed air valve opens by system logic when bleed air pressure is available

Question 16

APU bleed switch OFF light illuminates for what reason?

Answer 16

OFF illuminated (amber) –
• the valve is closed because a duct leak has occurred
• the valve is failed closed, or
• the switch is off, or
• the APU fire switch is pulled

Question 17

Bleed Isolating (ISLN) Switches when AUTO is illuminated? And when AUTO is not illuminated?

Answer 17

AUTO illuminated, The bleed isolation valve is controlled automatically

AUTO not illuminated, the bleed isolation valve is commanded closed

Question 18

When bleed isolation switch CLOSED illuminated?

Answer 18

CLOSED illuminated (amber) –
• the valve is closed because a duct leak or bleed loss has occurred, or
• the valve is failed closed, or
• the switch is off

Question 19

What part of the Pack control is automatic?

Answer 19

Pack control, zone temperature control, cabin air recirculation, fault detection, and overheat protection are all automatic.

Backup system control modes operate
automatically in the event of system failures

Question 20

What are the 6 temperature zones controlled by the Packs?

Answer 20

the flight deck, supernumerary cabin, forward and aft main deck cargo zones, and the forward and aft lower cargo compartments.

Question 21

Each pack is controlled how?

Answer 21

by two redundant channels in one of two separate
controllers. If one channel fails in a controller, control of the respective pack is continued automatically by the redundant channel in that controller

Question 22

Pack control, fault detection, and overheat protection are all automatic, what will the pack do if one of these fault are detected? And can it be reset and how?

Answer 22

If an overheat or other significant pack fault is detected, the pack shuts down automatically.

An attempt to restore pack operation may be made by pressing the AIR COND RESET switch

Question 23

What is the back up mode for the normal Pack operation mode?

Answer 23

Standby cooling mode

Question 24

With one pack working normally and the other in the back up STBY COOLING mode, how does the standby cooling pack operate?

Answer 24

the pack in standby cooling mode shuts down at lower altitudes and higher outside air temperatures when ambient conditions do not permit standby cooling.
The pack restarts automatically when altitude and outside air temperatures are suitable for
standby cooling

Question 25

If both packs are in standby cooling mode, or if one pack is inoperative and the other pack is in standby cooling mode, how will the pack system operate?

Answer 25

the packs or pack operates continuously to
maintain cabin pressurization, regardless of altitude or outside air temperature

Question 26

Which pack supplies air the flight deck and supernumerary cabin and for what purpose?

Answer 26

The flight deck and supernumerary cabin receive 100% fresh conditioned air from the left pack.

To prevent smoke and objectionable odors from entering the occupied compartments, the flight deck and supernumerary cabin are maintained at a slightly higher pressure than the main deck cargo and lower cargo compartments.

Question 27

How do the recirculation fans circulate the air?

Answer 27

The fans draw cabin air through filters, then reintroduce the air into the cargo conditioned air distribution system

Question 28

After recirculation fans reintroduce air into the cargo conditioned air distribution system and mixes with pack air, where does is go from there?

Answer 28

Into the main cargo deck compartment, then flows into the lower deck, where it is either exhausted overboard through outflow valves or drawn into the
recirculation system

Question 29

When the M/D FLOW switch is in normal mode how does the Air Flow Rate System operate?

Answer 29

Normal flow mode is intended for most cargo types on the Main Deck Cargo compartment. During flight it schedules a lower airflow setting which conserves
fuel.
Additionally, the left recirculation fan does not operate during Normal flow mode

Question 30

What is High Flow mode intended for on the M/D FLOW switch?

Answer 30

High flow mode is intended for carrying live animals or perishable cargo. During High flow mode, all six shut-off valves are open. In High Flow mode the cruise fuel burn increase is expected to be an additional 0.1% to 0.2%

Question 31

During a “Class E” Main Deck Cargo fire fighting mode…

Answer 31

…all six shut-off valves close.

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