2 Air Systems Flashcards
The air condition Pack control, zone temperature control, fault detection, and overheat protection
are all:
Automatic
The airplanes air condition is divided into three temperature zones:
Flight deck and two cabin
zones.
How many air conditioning packs are there?
Two
In which case are the packs output limited?
During high bleed air demand periods (such as during takeoff/landing or with an
engine inoperative). Pack output is further reduced when the main cargo fire
suppression system is activated.
Pack selector in AUTO, pack output temperature is determined by?
The left and right cabin temperature controllers:
Pack selector in STANDBY, pack output temperature is determined by?
The position of the pack selector:
- N (normal) - constant, moderate temperature
- W (warm) - full warm.
Are you able to get conditioned air without the use of the packs?
Yes. When a ground source of conditioned air is available.
L or R PACK TEMP means?
All pack control system faults or overheats.
An automatic control system fault or a pack outlet overheat requires:
Crew interaction
When an internal
pack overheat is detected:
The pack valve closes and the pack is shut down automatically.
PACK TEMP and L or R PACK OFF EICAS massage will be displayed together when?
When an internal
pack overheat is detected.
The pack controllers regulate the pack output air temperature to satisfy the
temperature requirement of the compartment requiring:
The coolest air
What does trim air?
Trim air adds hot air from the bleed air system to the to hottest compartments.
What does FLT DECK TEMP, FWD CABIN TEMP or AFT CABIN TEMP mean?
Zone temperature controller failure, compartment temperature control is in the OFF position (FWD and AFT
CAB only) or trim air switch is OFF
TRIM AIR means?
TRIM AIR switch is off
What happens when the trim air system is off?
The packs attempt to maintain all compartments at an average temperature.
The forward equipment cooling system supplies:
Cooling air to equipment in the
forward electronic equipment racks and the flight deck avionics.
FWD EQPT VAL means?
The system valves fail to reconfigure during automatic operation.
FWD EQPT OVHT means?
Low airflow or high temperature is sensed.
FWD EQPT SMOKE means?
Smoke is sensed in the forward equipment cooling ducts.
FWD EQPT COOLING means?
No cooling airflow is sensed after selecting OVRD.
The cargo heat system are provided heat from?
The bleed air system.
Regarding the cargo heat system, the system automatically maintains compartment temperature
above:
Approximately 45°F (7°C)
The BULK CARGO HEAT selector allows a higher temperature to be selected for
the bulk compartment. With the
selector in the VENT position, the bulk compartment is maintained above
approximately:
65°F (18°C)
FWD, AFT or BULK CARGO OVHT means?
The cargo compartment
temperature is above the standard control range.
A compartment shutoff valve
closes automatically if a compartment temperature exceeds:
approximately 90°F
(32°C). When the compartment temperature decreases below the overheat temperature setting the OVHT light extinguishes, the EICAS message is removed, and the compartment shutoff valve re-opens.
The Main Deck Temperature Selector determines which of two separate temperature control ranges will apply. Those are:
- ANIMAL/NORM: Suitable for cargo such as live animals that require moderate temperatures.
- PERISHABLE: Suitable for carrying cargo requiring cooler than moderate temperatures.
Cabin pressurization is controlled by:
Adjusting the discharge of conditioned cabin
air through the outflow valve.
What protects the
fuselage against excessive pressure differential?
The positive pressure relief valves and negative pressure relief doors.
The pressurization system can be operated in which modes?
Automatic and manual
What happens if the pressurization system in automatic mode fails?
It is automatically switched to the other auto mode. AUTO 1 to AUTO 2 or vice versa.
How is the cabin pressurization
schedule calculated in automatic mode?
The pressurization system uses ambient pressure data from
the air data system in
conjunction with the selected cabin auto rate, the takeoff
altitude and the indicated landing altitude.
How is the cabin pressurization during takeoff in automatic mode?
The system supplies a small positive pressurization to cause a smooth
cabin altitude transition.
How is the cabin pressurization during climb in automatic mode?
Cabin altitude increases on a schedule related to the takeoff field elevation, airplane altitude, and the selected auto climb rate limit.
What happens if the max cabin pressure differential is reached during climb?
Cabin climb rate becomes
a function of airplane climb rate, while maintaining the maximum differential
pressure.
Whitch altitude is selected for the cruise cabin altitude?
The higher of the landing
altitude and the scheduled cabin altitude.
What happens in the descent and landing in automatic mode regarding the pressuriziation system?
The cabin altitude decreases to slightly below the selected landing altitude. This ensures that the airplane lands pressurized.
During landing the pressuriziation system in automatic mode will ensure the airplane lands pressurized. The barometric pressure correction comes from?
The captain’s altimeter.
Regarding the pressuriziation system. What happens at touchdown?
The outflow valve opens to depressurize the airplane.
CABIN ALTITUDE means?
The cabin altitude is above 10,000 feet.
When will the CABIN ALTITUDE message be removed?
When the cabin altitude descends below 8,500 feet.
CABIN AUTO INOP means?
Automatic pressurization control fails or when cabin
altitude MODE SELECT is MAN
How is the positive pressure relief valves and negative pressure relief doors operated in conjuction with the pressuriziation control system?
It is not. It operate independently to protect the fuselage against excessive pressure differential.
What happens when the cabin altitude exceeds 11,000 feet?
The system automatically close the outflow valve.
Bleed air can be supplied by?
The engines, APU, or a ground air source.
Bleed air is used for?
- air conditioning
- pressurization
- engine start
- wing and engine anti-ice
- center hydraulic system air driven pump (ADP)
- hydraulic reservoir pressurization
When is the HP air used in the beed air system?
During descent and other low power setting operations.
The engine bleed air valves may close when?
- The APU is starting either engine.
- Ground pneumatic air is
connected - During periods of low engine bleed air demand (such as when the air conditioning packs are off)
L or R ENG BLEED OFF means?
The engine bleed air valve is closed for a system fault.
L or R ENG BLD OVHT means?
The engine bleed air temperature is excessive.
L or R ENG HPSOV means?
The engine high pressure bleed air valve is open when
commanded closed.
L or R ENG PRV means?
The pressure regulating valve is open when commanded closed.
The APU bleed air is available up to?
17,000 feet.
What prevents reverse flow of bleed air from the duct into the APU?
The check valve in the APU supply line.
APU BLEED VAL means?
The APU bleed valve position disagrees with the commanded
position.
The L and R bleed air isolation valves are normally closed. Except for?
Engine start or single bleed
source operation.
The center bleed air isolation valve is normally?
In the open position.
C, L or R BLD ISLN VAL means?
The bleed isolation valve position disagrees with
the commanded position.
L or R BLD DUCT LEAK, BODY DUCT LEAK or STRUT DCT LEAK means?
A high temperature bleed air leak is detected.
L or R ENG BLD OVHT means?
A higher than normal temperature is detected by the bleed air temperature sensor.
What happens automatically if a bleed overheat occurs?
The engine bleed air valve is automatically closed
If a bleed overheat situation has occured and the engine bleed air valve is closed. What will happen if engine anti-ice is activated?
It will cause the PRV to open to provide cowl anti-ice unless a strut duct leak exists.
