2 Air Systems

AUTO 1 or AUTO 2. If the selected auto mode fails, control is automatically switched to the other auto mode.
FCOM 2.20.9

How is pressurization maintained?

Spring - loaded to center.
Controls cabin outflow valve position with the Cabin Altitude Mode Selector in
manual (MAN) mode.

What does manual mode control?

Thrust Lever Position
Cabin Pressure
Air/Ground Logic
Barometric Corrected Altitude

What type of information do the controllers receive?

Controller uses a seperate AC Bus and motor

How are the 2 outflow valves operated?

28V DC motor

How is the outflow valve powered in manual mode?

Outflow valve closes

What happens when the cabin altitude reaches 11,000 feet in manual mode?

Illuminated (amber) -6
� AUTO 1 and AUTO 2 cabin altitude control functions are inoperative
� MAN mode is selected.
FCOM 2.10.11

What does the AUTO INOP light mean?

Ascend: 500 FPM
Descent: 300 FPM
FCOM 2.10.11

What is the normal rate of climb and descent in the cabin?

When a/c is powered up

When is the system tested?

Fully opened.

What is the outflow valve doing during the test?

For takeoff, the system supplies a small positive pressurization to cause a smooth cabin altitude transition.
FCOM 20.3.1

What is T/O mode?

During descent, cabin altitude decreases to slightly below the selected landing altitude. This ensures that the airplane lands pressurized. Landing altitude
barometric pressure correction comes from the captain's altimeter.
FCOM 20.3.2

What is landing mode?

Illuminated (red) -
� cabin altitude exceeds 10,000 feet
� extinguishes when cabin altitude descends below 8,500 feet.
FCOM 2.10.12

When does the Cabin Alt. Warning go off, and when does it stop?

14,000' Cabin Alt.

When do PAX O2 masks deploy?

4 DUCT LEAK Light
Illuminated (amber) - a high temperature bleed air leak is detected in the center
pneumatic duct.
FCOM 2.10.13

DUCT LEAK Light

Compartment Temperature Inoperative (INOP) Lights
Illuminated (amber) -
� fault in the zone temperature controller
� the Compartment Temperature Control is OFF
� the trim air switch is OFF.
FCOM 2.10.3

Compartment Temperature Inoperative (INOP) Lights

4 TRIM AIR Switch
ON - the trim air valve is commanded open.
Off (ON not visible) - the trim air valve is commanded closed.
FCOM 2.10.3

TRIM AIR Switch

5 Trim Air OFF Light
Illuminated (amber) - the TRIM AIR switch is off.
FCOM 2.10.4

Trim Air OFF Light

7 PACK RESET Switches
Push - resets an overheated pack if the pack has cooled to a temperature below the overheat level.
FCOM 2.10.4

PACK RESET Switches

8 Pack Inoperative (INOP) Light
Illuminated (amber) -
� the pack is overheated
� fault in the automatic control system.
FCOM 2.10.4

Pack Inoperative (INOP) Light

14 PACK Control Selectors
OFF - closes the pack valve.
AUTO - the pack is automatically controlled.
STBY -
� N (normal) - regulates the pack outlet temperature to a constant,
moderate temperature.
� C (cool) - sets the pack to full cold operation.
� W (wa

PACK Control Selectors function ?

1 Equipment (EQUIP) COOLING Selector
AUTO - automatically controls equipment cooling system.
STBY - positions equipment cooling system for inboard air flow.
OVRD - positions equipment cooling system for reverse air flow.
� shuts down Nitrogen Generation S

Equipment (EQUIP) COOLING Selector
AUTO -
STBY -
OVRD -

2 NO COOLING Light
Illuminated (amber) -
� active in OVRD only
� no reverse air flow through the E/E compartment avionics.

NO COOLING Light

3 VALVE Light
Illuminated (amber) - equipment cooling valves are not in their commanded
position.

VALVE Light

4 Overheat (OVHT) light
Illuminated (amber) - high temperature or low airflow in the equipment cooling
system.

Overheat (OVHT) light

5 SMOKE Light
Illuminated (amber) - smoke in the equipment cooling system.

SMOKE Light