CH2 AIR SYS Flashcards
(236 cards)
1
Q
What does the AUTO setting on the Forward Equipment Cooling Switch indicate?
A
Forward equipment cooling mode is controlled automatically.
2
Q
What happens when the Forward Equipment Cooling Switch is turned Off?
A
Both forward equipment cooling supply fans and vent fan are commanded off, smoke/override valve is commanded open, forward cargo heat becomes inoperative, forward cargo air conditioning becomes inoperative, and OVRD illuminates.
This setting is typically used in emergencies or specific operational scenarios.
3
Q
What does the illuminated OVRD (amber) indicate?
A
Smoke/override mode is operating due to manual off selection, supply fan failure, or automatic selection by the smoke detection system.
4
Q
What is the function of the Flight Deck Temperature Control?
A
Selects the target flight deck temperature between 18° C and 29° C.
Turning the control toward C or W adjusts the desired temperature.
5
Q
What is the mid position setting on the Flight Deck Temperature Control?
A
Approximately 24° C.
6
Q
What occurs during ground operations when the Flight Deck Temperature Switch is set to full C or W?
A
The flight deck boost fan may be commanded on, increasing flight deck air flow and slightly reducing passenger cabin air flow.
7
Q
What does the AUTO position on the PACK Switches indicate?
A
The pack is automatically controlled
8
Q
What does it mean when the PACK Switch is set to OFF (amber illuminated)?
A
Both associated cabin air compressors are not running
This can occur automatically during engine start, due to pack or compressor high temperature, or when manually selected.
9
Q
What happens when the TRIM AIR Switch is set to ON?
A
The trim air valve is commanded open
10
Q
What does it mean when the TRIM AIR Switch is in the OFF position (ON not visible)?
A
The trim air valve is commanded closed and FAULT illuminates
11
Q
What does an illuminated FAULT (amber) indicate for the TRIM AIR Switch?
A
The trim air valve is failed closed or commanded closed due to overheat
It may also indicate that the TRIM AIR switch has been selected off.
12
Q
What does the ON position indicate for the Recirculation Fans (RECIRC FANS) Switches?
A
Provides automatic operation of the associated recirculation fans
13
Q
What occurs when the Recirculation Fans (RECIRC FANS) Switch is set to OFF (ON not visible)?
A
The selected recirculation fans do not operate
An EICAS advisory message is displayed in this case.
14
Q
What does the EQUIP COOLING AFT switch set to AUTO control?
A
Aft equipment cooling mode is controlled automatically.
15
Q
What occurs when the EQUIP COOLING AFT switch is set to Off?
A
Both aft equipment cooling supply fans and vent fan are commanded off, override valve is commanded open, and aft cargo heat becomes inoperative.
OVRD ILLUMINATES
16
Q
What does the OVRD indication mean?
A
SMOKE/OVRD mode is operating due to manual selection of Off, failure of both equipment cooling supply fans, or automatic selection by the smoke detection system.
17
Q
What is the function of the CABIN TEMP control?
A
Provides automatic passenger cabin temperature control.
18
Q
What temperature range can the CABIN TEMP control set?
A
Between 18° C and 29° C.
19
Q
What does the Air Conditioning Reset (AIR COND RESET) Switch do?
A
Resets air conditioning faults and attempts to restart normal operation
It also resets any trim air valves held closed due to overheat, control failure, or valve failure, attempts to reset a failed recirculation fan, and resets fault protection.
20
Q
What are the two positions of the Alternate Ventilation (VENTILATION) Switch?
A
NORM and ALTN
21
Q
What happens when the Alternate Ventilation (VENTILATION) Switch is set to ALTN?
A
The Forward and Aft Outflow Valves are repositioned towards the ten and one o’clock positions when below 13,000 ft altitude and not on ground.
22
Q
What are the two types of heaters mentioned in the air conditioning system?
A
- Shoulder Heaters
- Foot Heaters
23
Q
What does pushing the Air Conditioning Reset (AIR COND RESET) Switch attempt to reset?
A
- Air conditioning faults
- Trim air valves
- Failed recirculation fan
- Fault protection
24
Q
What is the significance of the NORM position in the Alternate Ventilation (VENTILATION) Switch?
A
Environmental control system is configured for normal operation
25
What does the SHOULDER HEATER Control LOW setting indicate?
The electric heater operates on low setting.
## Footnote
The shoulder heater adds heat to the conditioned air at variable temperature settings up to HIGH
26
What is the function of the SHOULDER HEATER Control when turned?
The electric heater adds heat to the conditioned air flowing in at shoulder level at variable temperature settings up to HIGH.
## Footnote
Available in-flight only.
27
What does the FOOT HEATER Control LOW setting indicate?
The electric heater is off.
## Footnote
The foot heater adds heat to the floor plate at variable temperature settings up to HIGH.
28
What happens when the FOOT HEATER Control is turned?
The electric heater adds heat to the floor plate at variable temperature settings up to HIGH.
## Footnote
Available on ground and in-flight when pack and recirculation fans are on.
29
Fill in the blank: The SHOULDER HEATER is available _______.
in-flight only.
30
Fill in the blank: The FOOT HEATER is available on ground and in-flight when _______.
pack and recirculation fans are on.
31
What does the LOW setting on the FWD CARGO FLOW selector indicate?
Normal ventilation flow for maintaining perishable, temperature sensitive, or any cargo other than animal carriage
32
What is the function of the HIGH setting on the FWD CARGO FLOW selector?
High ventilation flow demanded from the air conditioning system to prevent cargo odors from entering the passenger cabin
## Footnote
This setting is also used for live animal carriage or other odorous cargo.
33
Fill in the blank: The FWD CARGO A/C control provides _______ for the forward cargo compartment.
automatic temperature control
34
True or False: The LOW setting on the FWD CARGO FLOW selector is suitable for live animal carriage.
False
## Footnote
The LOW setting is for normal cargo, while HIGH is used for live animals or odorous cargo.
35
What does the Forward Cargo Air Conditioning Control provide?
Automatic temperature control for the forward cargo compartment
36
What temperature range can be set using the Forward Cargo Air Conditioning Control?
4° C to 27° C
## Footnote
The mid position (12 o'clock) approximately sets the temperature to 16° C.
37
What happens when the Forward Cargo Air Conditioning Control is turned to OFF?
Disables heater and cargo refrigeration unit
## Footnote
Normal cargo heating is provided by the forward E/E exhaust ventilation system.
38
What is the target temperature when the BULK CARGO TEMP switch is set to AUTO?
21° C
39
What indicates that the BULK CARGO TEMP switch is commanded off?
AUTO not visible
40
What does an OFF light illuminated amber indicate for the BULK CARGO TEMP switch?
Bulk cargo heater overheat or switch selected off
41
What does the OFF light status signify when not visible for Forward Cargo Air Conditioning?
FWD cargo air conditioning selector is OFF or functioning properly
42
What indicates that the Forward Cargo Air Conditioning is inoperative?
OFF light illuminated amber when selector is in any position other than OFF
43
Fill in the blank: The Forward Cargo Air Conditioning Control allows setting the desired target temperature between _______.
4° C and 27° C
44
True or False: The Forward Cargo Air Conditioning Control can only provide cooling and not heating.
False
## Footnote
It can disable the heater and provide normal heating through the exhaust ventilation system.
45
What does the HUMID switch control?
Flight deck humidification system operates automatically when ON
## Footnote
The HUMID switch is located on the overhead panel.
46
What does the AUTO position of the OUTFLOW VALVE switch indicate?
Outflow valve controlled automatically
47
What happens when the MAN position of the OUTFLOW VALVE switch is selected?
Outflow valve is controlled manually
## Footnote
This bypasses automatic outflow valve control and cabin altitude limiter, and AUTO extinguished
48
How is the landing altitude set manually using the Landing Altitude (LDG ALT) Selector?
Pull ON, then rotate
## Footnote
Landing altitude followed by MAN displayed on EICAS
49
What happens when the LDG ALT Selector is pushed?
Landing altitude set automatically from FMS
## Footnote
Landing altitude followed by AUTO displayed on EICAS
50
When are pressurization system indications displayed automatically?
When landing altitude is set to MAN
EITHER OUTFLOW VALVE MAN
CABIN ALT ABOVE NORMAL RANGE
CABIN DIFF PRESS ABOVE NORMAL
AIR SYNOPTIC
SELECTED EICAS MSG
51
What color indicates a normal cabin altitude?
White
## Footnote
Indicates that the cabin altitude is within the normal range.
52
What does an amber cabin altitude indication signify?
Above normal range
## Footnote
Indicates that the cabin altitude is higher than the normal range.
53
What does a red cabin altitude indication represent?
Excessive cabin altitude
54
What does a plus sign (+) in cabin altitude rate indicate?
Rate of climb
55
What does a minus sign (-) in cabin altitude rate indicate?
Rate of descent
56
What color indicates a normal cabin differential pressure?
White
## Footnote
Indicates that the cabin differential pressure is within the normal range.
57
What does an amber cabin differential pressure indication signify?
Above normal range
## Footnote
Indicates that the cabin differential pressure is higher than the normal range.
58
What does a red cabin differential pressure indication represent?
Excessive cabin differential pressure
59
What does 'M' (amber) indicate in Outflow Valve Control Source?
Manual control
60
What does a blank indication in Outflow Valve Control Source signify?
Automatic control
61
What does 'OP' stand for in Outflow Valves Position?
Open
62
What does 'CL' stand for in Outflow Valves Position?
Closed
63
What does the pointer in Outflow Valves Position indicate?
Varies position to reflect outflow valve position from open to closed
## Footnote
Provides a visual representation of the outflow valve's status.
64
What does 'AUTO' (white) indicate in Landing Altitude Selection?
Altitude set automatically from FMC
65
What does MAN (amber) indicate in the pressurization system?
Altitude set by landing altitude (LDG ALT) selector.
66
What is the purpose of the Power Electronics Cooling System (PECS)?
It is the liquid cooling system for electronics.
67
How can the status display for PECS be viewed?
Push a Systems (SYS) display switch, then select the status (STAT) synoptic key.
68
What does the liquid quantity display show?
Left and right system reservoir quantities as a percentage of normal service level.
1.00 IS NORMAL
69
What does LO (amber) indicate on the liquid quantity display?
The reservoir requires servicing.
70
What does RF (white) indicate on the liquid quantity display?
Reservoir servicing is recommended.
71
What does OF (white) indicate on the Liquid Quantity Display?
Displayed when the reservoir is over-full
72
When is a single liquid cooling loop displayed?
When only one forward external power source is connected and selected ON
73
What happens to the forward cargo selected temperature display when the forward cargo air conditioning system is off or inoperative?
The display is blank.
## Footnote
This indicates that no temperature is being selected for the forward cargo compartment.
74
What does a green symbol indicate in the Cabin Air Compressor Synoptic Indications?
The associated compressor is running and developing flow.
## Footnote
This is a key indicator for the operational status of the cabin air compressor.
75
What does a white symbol indicate in the Cabin Air Compressor Synoptic Indications?
The associated compressor is not developing flow.
## Footnote
This indicates that the compressor is off and not functioning.
76
Fill in the blank: Selected temperatures are indicated in _______.
magenta
77
Fill in the blank: Actual temperatures are indicated in _______.
white
78
What does a white, low-intensity indicator for the compressor signify?
Compressor invalid: Signal from associated compressor is invalid or missing
79
What does the load shed symbol (white) indicate regarding associated compressors?
Associated compressor (L1, L2, R1, R2) has load shed
80
What does a green pack symbol indicate?
Pack is running and developing conditioned airflow
81
What does a white pack symbol signify?
Pack switch - OFF or both associated cabin air compressors are off and not PACK L(R) status message
82
What does an amber pack symbol indicate?
Pack is not developing conditioned inflow when commanded to run
PACK SW AUTO AND PACK LR STATUS MSG
83
What does a 'Pack signal invalid' indication look like?
White, low intensity.
## Footnote
Indicates that the pack signal is not correctly functioning.
84
What does a green indication for the Recirculation Fan signify?
Fan on - Upper fan or one of two lower fans is developing flow.
85
What does a white indication for the Recirculation Fan signify?
Fan off - Upper fan or both lower fans are not running.
86
What does a white, low intensity indication for the Recirculation Fan indicate?
Fan invalid on.
87
What does a green symbol indicate in the Trim Air Valve Synoptic Indications?
Valve open
88
What does a white symbol represent in the Trim Air Valve Synoptic Indications?
Valve closed
89
What does an amber symbol indicate in the context of Trim Air Valve Synoptic Indications?
Valve failed open or Valve failed closed
90
What does a low intensity white symbol signify in the Trim Air Valve Synoptic Indications?
Valve invalid
91
What is the indication for an associated pack in standby cooling mode?
EICAS advisory message PACK MODE L (R) displayed.
92
What does the EICAS advisory message ANTI-ICE PACKS indicate?
Compressor inlet anti-ice failure.
93
What is displayed when the cabin occupants data is missing or invalid?
Blank.
## Footnote
The system does not provide information on cabin occupants if data is not entered correctly.
94
Fill in the blank: The number of cabin occupants is entered on the _______.
Cabin Attendant Panel
95
What is the primary function of the air conditioning system in an airplane?
To supply conditioned outside air and recirculated cabin air at a controlled temperature throughout the airplane.
96
Which areas does the air conditioning system supply conditioned air to?
* Flight deck shoulder heaters
VENTILATION FOR
* Galleys
* Lavatories
* Overhead crew rest compartments
97
What are some of the automatic functions of the air conditioning system?
* Pack control
* Zone temperature control
* Cabin air recirculation
* Fault detection
* Overheat protection
98
How many temperature zones is the airplane divided into?
Seven temperature zones: the flight deck and six passenger cabin zones.
99
What happens in the event of system failures in the air conditioning system?
Backup system control modes operate automatically.
100
Fill in the blank: The flight deck VENTILATION switch in _______ position indicates the ventilation system is in the alternate mode.
ALTN
101
What advisory message is displayed on the EICAS when the ventilation system is in alternate mode?
VENTILATION ALTN
102
True or False: Zones A and B in the airplane's air conditioning system do not contain sub-zones.
False
103
Name the sub-zones contained in Zones A and B.
* Al
* Bl
104
What is the purpose of deflector doors in the Air Conditioning Packs?
To prevent debris from entering the CACs during normal ground operations and landing phases of flight
## Footnote
Deflector doors may retract when ambient air temperature is below 2°C or above 35°C.
105
How many electric cabin air compressors (CAC) supply outside air to the air conditioning packs?
Four CACs
## Footnote
Two CACs are dedicated to each of the two air conditioning packs.
106
What happens if one pack control system fails?
Pack control automatically switches to the other system.
107
During high demand periods, what happens to the CAC output?
It is increased automatically to compensate for a failed pack.
108
What is the recommended mode for air conditioning packs during ground operations?
AUTO
109
What is used for ground operation cooling when sufficient main A/C Bus power is available?
A ram fan
110
What should be done before and during the use of external conditioned air?
Packs and lower recirculation fans must be selected off.
111
What happens to the CACs during cold weather operations?
Both CACs in each pack are commanded on.
112
When is three CAC operation automatically enabled?
Two minutes after both engines are running.
113
What is the status of all CACs during the initial start sequence of normal engine starts?
All CACs are commanded off.
114
What indicates a fault if PACK messages show for more than one minute after the second engine is running?
This should be considered a fault indication.
115
Fill in the blank: A ground source of conditioned air can be used to supply conditioned air directly to the _______.
cabin distribution system
116
True or False: Packs restart immediately after the second engine is running if both engines are started together.
False
## Footnote
Packs do not restart until at least the time limit is met. 2 MINS
117
What messages can show approximately 30 seconds after the second engine is running?
PACK L and PACK R messages.
SHOULD BLANK 20 SECS LATER IF THERE OVER A MIN CONSIDER A FAULT
118
What happens when an overheat or significant pack fault is detected in the air conditioning packs?
The pack shuts down automatically and the EICAS advisory message PACK (L, R) is displayed.
119
What is the purpose of pressing the AIR COND RESET switch below 34,000 feet?
It attempts to restore pack operation by temporarily reducing the CAC flow schedule of the operating pack.
120
What occurs to the CACs above 34,000 feet during an attempt to reset an inoperative pack?
The CACs are close to the surge margin, which may prevent the reset of the inoperative pack.
121
During a go-around with one engine inoperative, what may happen to the packs?
Both packs could temporarily load shed, and the PACK L+R message may show momentarily.
122
What is standby cooling mode in the context of air conditioning packs?
A backup mode automatically used for certain internal malfunctions where the EICAS advisory message PACK MODE (L, R) is displayed.
ALSO STBY COOLING ON AIR SYNOPTIC
123
What happens to the pack in standby cooling mode at lower altitudes and higher outside air temperatures?
It shuts down when ambient conditions do not permit standby cooling.
124
What role do recirculation fans play in the cabin air distribution system?
They assist the packs to maintain a constant ventilation rate through the cabin.
125
What type of air does the flight deck receive?
100% conditioned outside air.
126
How is outside air flow affected during failure conditions?
It is reduced to protect the electrical power distribution system.
127
What can cabin attendants do regarding outside airflow to the cabin?
They can reduce outside airflow based on the number of airplane occupants.
128
Fill in the blank: The EICAS advisory message displayed when one pack is in standby cooling mode is _______
PACK MODE (L, R)
129
True or False: In standby cooling mode, pack cooling capacity may be greater than in normal mode.
False
PACK COOLING CAPACITY LESS THAN NORMAL MODE AND MAY RESULT IN WARM FLT DECK OR CABIN TEMPS AT LOWER ALTS
130
What happens to air exhausted from the passenger cabin?
It flows into the upper recirculation system or to the lower deck for exhaustion overboard or recirculation.
131
What is the purpose of the lower recirculation system in an air conditioning system?
To mix air from recirculation fans with pack air before entering distribution ducts
132
How does lower recirculation cooling affect power requirements from CACs?
It reduces the power required from the CACs
133
What system provides lower recirculation cooling?
Integrated Cooling System (ICS)
134
What happens when the upper and/or lower RECIRCULATION FAN switches are OFF?
An EICAS advisory message RECIRC FAN UPR and/or LWR OFF is displayed
135
True or False: Turning off the recirculation fans increases the amount of fresh air to the passenger cabin.
False
JUST REDUCES IN DECREASED AIRFLOW
136
What must remain ON during hot weather operations unless a non-normal checklist directs otherwise?
Recirculation fans
137
Where is the de-humidification system located in the passenger compartment?
In the crown area OF PAX COMPARTMENT
138
How does the de-humidification system operate?
Automatically when electrical power is available
TWO DRYERS FWD AND AFT REMOVE MOIST AIR FROM CROWN AREA AND EXHAUST BELOW CABIN FLOOR
139
What does the Alternate Ventilation System (AVS) provide?
An alternate means of ventilating the cabin and flight deck when both packs are inoperative
140
What happens when the airplane is un-pressurized and the AVS switch is in ALTN position?
The FWD and AFT outflow valves allow fresh outside air to be drawn into the air distribution system
141
What is added to the pack conditioned air to control temperature in each zone?
Hot trim air from each pack
142
How many temperature zones does the cabin have?
Seven temperature zones
143
What is the range for the CABIN TEMP selector's master reference temperature?
Between 18° C and 29° C
144
How can target temperatures for each passenger cabin zone be modified?
Plus or minus 3° C, within the range of 18° to 29° C, using the cabin management system
145
What temperature range does the flight deck temperature selector set?
Between 18° and 29° C
146
What is the temperature range set by the flight deck temperature selector?
18° to 29° C
147
What regulates the pack outlet temperature when the flight deck or cabin temperature setting is unavailable?
Last temperature set or average cabin temperature of 24° C
148
How can the Overhead Flight Crew Rest area temperature be controlled?
Manually by the heater controls in the compartments
149
In case of loss of trim air, what do cabin temperature controllers attempt to maintain?
All zones at the average target temperature
150
What is the function of the flight crew shoulder heat system?
Provided by electric elements in the side window air diffusers
IN FLT ONLY
151
When does the humidification system operate automatically?
20 minutes into cruise above 25,000 ft
152
What happens to the humidification system approximately 1-1.5 hours prior to touchdown?
Automatically switched off
153
What type of temperature control system is present in the forward and bulk cargo compartments?
Independent temperature control systems
154
What is the temperature control situation in the aft cargo compartment?
Temperature is uncontrolled
155
What separates the aft and bulk cargo compartments?
An insulated curtain
156
Fill in the blank: Flight deck temperature can be adjusted using the _______.
CABIN TEMP selector
WHEN ALTN VENTILATION IN USE
157
True or False: Foot heaters are available only when the aircraft is on the ground.
False
158
What is the purpose of the forward cargo compartment air conditioning system?
To provide temperature control and conditioned air for transporting perishable, live, or other temperature-sensitive cargo.
159
What components provide ventilation and conditioned air in the forward cargo compartment?
* Forward E/E cooling exhaust
* Dedicated refrigeration unit
* In-line electric heaters
* Forward cargo exhaust fan
160
What does the FWD CARGO FLOW selector do?
Controls ventilation to prevent or remove cargo odors from the passenger cabin.
161
What temperature range can the flight crew set for the forward cargo compartment?
Between 4° and 27° C.
162
What happens if the flight deck control fails in the forward cargo compartment?
The packs maintain the last selected target temperature.
163
What does the EICAS advisory message 'CARGO A/C FWD' indicate?
A fault is detected in the forward cargo compartment air conditioning system.
164
How is ventilation and heat provided in the bulk cargo compartment?
From cabin air passing through a supply fan and in-line electric heaters.
165
What happens when the AUTO setting on the BULK CARGO TEMP switch is selected?
It turns on the bulk ventilation fan, if required, for live animal transport.
166
What occurs during an automatic overheat shutdown in the bulk cargo compartment?
Cargo heat to the related compartment cannot be restored in flight.
167
What does the EICAS advisory message 'CARGO HEAT BULK' notify the flight crew of?
When the switch is off or a shutdown occurs.
168
How is ventilation and heat provided in the aft cargo compartment?
From aft E/E cooling exhaust entering from below the compartment floor.
169
What additional heat source is present in the aft cargo compartment?
Some residual heat due to air leakage through the insulated curtain from the bulk cargo compartment.
170
What is the primary function of the forward equipment cooling system?
To direct cabin air to the equipment and ventilate warm exhaust air
## Footnote
The system uses internal fans and valves for this purpose.
171
What happens if the primary supply fan in the forward cooling system fails?
The backup supply fan operates automatically
## Footnote
There are two cooling system supply fans: a primary and a backup.
172
What are the conditions that trigger the forward system to reconfigure to override mode?
• FWD EQUIP COOLING switch selected to OVRD
• Both supply fans fail in flight
• Both flow sensors fail
• Low airflow detected in flight
• Excessive temperature detected in flight
• Smoke detected in the forward system or cargo area
• FWD CARGO FIRE ARM switch is ARMED
173
In override mode, what happens to the forward cargo heat and overboard vent valves?
They are closed
174
How does cabin differential pressure assist in the forward equipment cooling system?
It draws air through the flight deck panels and the forward E/E equipment racks to create a reverse flow of air
## Footnote
This air then exits through the override valve to an overboard venturi.
175
What is the effect of descent on airflow in the forward equipment cooling system?
Airflow decreases as the airplane descends due to reduced cabin pressure differential
176
What does the FWD EQUIP COOLING switch in OVRD do during flight?
It aids smoke evacuation from the flight deck
177
What alert is displayed on the ground if the forward equipment cooling system is inoperative?
EICAS advisory message EQUIP COOLING FWD
## Footnote
Additionally, the ground crew call horn in the wheel well sounds.
178
What is the primary function of the aft equipment cooling system?
To provide cooling air for the aft equipment bay and heating/ventilating air for the aft cargo compartment
## Footnote
The aft system operates similarly to the forward equipment cooling system.
179
True or False: The aft equipment cooling system uses external fans to ventilate warm exhaust air.
False
## Footnote
It uses internal fans and valves for this purpose.
180
How does the aft equipment cooling system ventilate warm exhaust air?
It directs warm exhaust air to a dedicated overboard exhaust valve or aft cargo compartment.
181
What components are involved in the aft equipment cooling system?
The system uses internal fans and valves, including two cooling system supply fans: a primary and a backup.
182
What happens if the primary supply fan fails?
The backup supply fan operates automatically.
183
When does the aft equipment cooling system reconfigure to override mode?
It reconfigures when:
* The AFT EQUIP COOLING switch is selected to OVRD
* Both supply fans fail in flight
* Both flow sensors fail
* Low airflow is detected in flight
* Excessive temperature is detected in flight
* The AFT CARGO FIRE ARM switch is ARMED
* Smoke is detected in the aft equipment cooling system or aft equipment ventilation system.
184
What occurs in override mode for the aft equipment cooling system?
The aft cargo heat and overboard exhaust valves are closed, the vent fan and both supply fans are commanded off, and the aft equipment cooling override valve is commanded to the override position.
185
How does cabin differential pressure affect air flow in the aft equipment cooling system?
It draws air through the aft E/E equipment racks to create a reverse flow of air across the equipment, then exits through the override valve to an overboard venturi.
186
What is the function of the AFT EQUIP COOLING switch in OVRD during flight?
It aids smoke evacuation from the passenger cabin.
187
What happens on the ground if the aft equipment cooling system is inoperative?
The EICAS advisory message EQUIP COOLING AFT is displayed and the ground crew call horn in the wheel well sounds.
188
What does the EQUIP OVBD VLV AFT message indicate?
It indicates that the aft equipment cooling overboard valve has failed in the open position.
189
Fill in the blank: The aft equipment cooling system uses _____ to direct cabin air to the aft equipment bay.
internal fans and valves.
190
What does the EQUIP OVBD VLV AFT message indicate?
The aft equipment cooling overboard valve is failed in the open position
## Footnote
This can lead to a large pressure differential between the cabin and equipment cooling duct.
191
What happens when the aft equipment cooling overboard valve is open?
Duct failure and subsequent loss of cabin pressure
## Footnote
This occurs due to the large pressure differential created.
192
What is the primary function of the lavatory/galley ventilation system?
Provides ventilating air for lavatories and galleys and smoke control
## Footnote
It also serves as a secondary heat sink for the Power Electronics Cooling System (PECS).
193
What does the Power Electronics Cooling System (PECS) do?
It is a liquid cooling system for the large motor power distribution system IN AFT EE EQUIP COMPARTMENT
## Footnote
PECS also provides cooling to supplemental cooling units and motor controllers.
194
How many independent liquid cooling loops does PECS consist of?
Two independent liquid cooling loops
## Footnote
Each loop has a single pump package with two fully redundant pumps.
195
What is the normal liquid coolant supply temperature controlled by PECS?
27° C
## Footnote
This is maintained during normal operation.
196
How is the operation of the Power Electronics Cooling System (PECS) controlled?
The operation is completely automated
197
What precaution must be taken after pack and hydraulic EMP shutdown regarding PECS?
A cool-down period is required to dissipate residual heat
## Footnote
This prevents damage to the units and degradation of the coolant.
198
What is the Integrated Cooling System (ICS) designed to do?
Provides cooling to galley carts and assists with cooling recirculated cabin air
## Footnote
The ICS is integrated with the air conditioning system and the liquid cooling system.
NO FLT DECK CONTROL
199
How is cabin pressurization controlled?
By regulating the discharge of conditioned cabin air through the outflow valves
200
Fill in the blank: The lavatory/galley ventilation system is also a _______ for the Power Electronics Cooling System.
secondary heat sink
201
How many outflow valves are installed in the pressurization system?
Two outflow valves: one forward and one aft
## Footnote
These valves help maintain cabin altitude and ventilation rates.
202
What protects the fuselage against excessive pressure differential?
Positive and negative pressure relief valves/vents
203
What modes does the pressurization system operate in during flight?
Climb mode, cruise mode, or descent mode
204
What data does the Cabin Pressure Control System (CPCS) use to calculate cabin pressurization?
Ambient pressure and flight plan data from the FMC
## Footnote
This ensures an optimal cabin altitude schedule.
205
What is the default cruise altitude if unavailable from the FMC in AUTO?
43,000 feet
206
During climb mode, how does cabin altitude change?
Cabin altitude increases on a schedule related to airplane climb rate and flight plan cruise altitude
## Footnote
This is designed to provide a smooth transition to cruise altitude.
207
What happens to cabin altitude during unplanned level segments or when VNAV is disengaged?
Cabin altitude remains constant as long as airplane altitude is not changing
## Footnote
This helps maintain pressure stability during flight.
208
What is the normal cabin altitude during cruise mode?
At or below 6,000 feet
## Footnote
Some degraded operations may allow it to climb as high as 8,000 feet.
209
What ensures the airplane lands pressurized during descent?
Cabin altitude decreases to slightly below the FMC planned landing altitude
210
Fill in the blank: The pressurization system has both _______ and manual operating modes.
automatic
211
What happens to the outflow valves at touchdown?
Both outflow valves open to depressurize the cabin.
212
What is the cabin altitude procedure for high altitude takeoffs above 8,000 feet?
The cabin descends to the target altitude while the airplane is climbing.
213
What occurs during high altitude landings if the destination airport elevation is greater than 8,000 feet?
The cabin altitude climbs to 6,000 feet after takeoff and remains there during cruise.
214
What happens to the cabin altitude as the airplane approaches the destination airport during high altitude landings?
The cabin altitude starts climbing to the destination airport elevation when appropriate.
215
What does the EICAS advisory message LANDING ALTITUDE indicate?
It indicates that landing altitude is unavailable from the FMC and not set in MAN.
216
What landing altitude does the cabin altitude controller assume if landing altitude is unavailable?
The cabin altitude controller assumes a landing altitude of 2,000 feet.
217
What occurs if a depressurization event happens?
The outflow valves close to preserve cabin pressure.
218
When do the outflow valves remain closed during a depressurization event?
They remain closed until the airplane descends below the cabin altitude limit.
219
What is the cabin altitude limit for takeoff/landing altitudes below 9,500 feet?
The cabin altitude limit is set to 11,500 feet.
220
What is the cabin altitude limit for takeoff/landing altitudes from 9,500 feet to 14,000 feet?
The cabin altitude limit is set to 14,500 feet.
221
What does the CPCS system prevent regarding cabin altitude?
It prevents the cabin altitude from exceeding 15,000 feet in the event of any probable failure or malfunction.
222
What should the flight crew avoid doing during the descent in a depressurization event?
The flight crew should not attempt to manually close the outflow valves.
223
How is the pressurization system set to manual operation?
By setting the OUTFLOW VALVE switches to MAN.
224
What are the steps for manually operating the pressurization system?
Set the OUTFLOW VALVE switches to MAN and hold the related OUTFLOW VALVE MANUAL switch to OPEN or CLOSE.
225
What displays the outflow valve position?
The outflow valve position is displayed on the EICAS display.
226
What should be done if the outflow valve position is not available on EICAS?
Hold the respective OUTFLOW VALVE MANUAL switch in the desired position for 30 seconds. FROM FULL OPEN TO CLOSE
227
What is the range for the landing altitude selector limits?
From -2,000 feet to 14,000 feet above sea level.
228
Fill in the blank: The pressurization system is in manual mode when the OUTFLOW VALVE switches are set to _______.
[MAN]
229
How can the FMC landing altitude be removed?
By pulling the LANDING ALTITUDE selector out to the detent
## Footnote
This action displays pressurization system indications on the EICAS display.
230
What are the two rates of adjustment for the landing altitude setting?
Low and high
231
What is the primary use of bleed air in the B787?
Engine core and inlet cowl anti-ice operations
232
Where is bleed air supplied from for engine anti-ice operations?
From a dedicated engine bleed port
233
When are the anti-ice valves armed?
When the ENGINE ANTI-ICE selectors are placed to AUTO
234
What triggers the opening of the anti-ice valves?
Ice detection system detects icing conditions or the selector is set to ON
235
What happens to the anti-ice valves when icing conditions are no longer detected?
The anti-ice valves close
## Footnote
They can also be closed if the selector is set to OFF.
236
List the conditions under which the engine anti-ice valves close automatically.
* During start
* For bleed air over temperature
* For bleed air overpressure
* When an engine fire switch is pulled
* When a bleed air leak is detected
