Air Conditioning and Cooling System Flashcards
How many temperature control zones?
5
However technically 7 because A and B
are divided up into A1 A2 B1 B2
Describe the Air Conditioning System
2 Packs
each powered by 2 electrical CAC’s
All control is Automatic
What can be done if both Packs become inop?
Alternate Ventilation systems switch
guarded on the bottom of the panel
What is the Automatic Temperature for the Baggage
21 degrees for FWD and Bulk
AFT is heated but not controlled
(AFT NO live animals)
Describe the Equipment cooling system
FWD and AFT E/E
Miscellaneous E/E
Where does the heat from the FWD E/E go
What does it cool?
FWD Cargo Compartment
also cools the FWD E/E and flight deck equip
Where does the hear from the AFT E/E go
AFT Cargo and Bulk Compartment
only source of heat for the AFT compartment
What does the Miscellaneous E/E cooling system cool
Inflight Entertainment (IFE)
What are the Fluid cooling systems
Power Electronics Cooling System (PECS)
Integrated Cooling System
What is PECS
Power Electronics Cooling System
Liquid cooling system for the Large motor power distribution system in the AFT E/E equipment compartment
cools the integrated cooling system as well
fluid is 50/50 anti freeze/water
Orange
What is the ICS
integrated cooling system provides refrigeration for galley carts
How is the pressurization controlled
fully automatic by the FMC
can be manual
When are the CAC’s load shed?
When ground eng start
When do the CAC inlet deflector door operate?
on the ground and < 1,000 ft
retract in extreme temps > 35 degrees < 2 degrees
What is the purpose of the pack
to turn Hot, Moist air –> Cold, Dry air
7 steps
What are the 7 steps for conditioning air in the packs
heat exchanger compressor heat exchanger condensor turbine T1 condensor (cools coils) Turbine T2
(T1 &T2 drive the compressor together all 3 are the Air cycle machine ACM)
How is warm air provided
from the Trim Air System
hot air from the 2 CAC’s per side
Which Zones are heated from which Trim Heat?
Right - A C
Left - B D
flight deck from both L & R
Describe the Recerc Fans system
Upper
passenger area
Lower system
Baggage area
(filters air and reintroduces it)
How is the Flight Deck different than the cabin?
100% outside air
slightly higher pressure to prevent smoke
Describe the Humidity systems
Humidification system in the flight deck
De-humidification system in the cabin, 2 Zonal dryers
moist air exhausted below cabin floor
What are the temp ranges?
FLT Deck 18-29 degrees
(12 o’clock is usually 24 deg)
Cabin Temp 18-29 deg
(12 O’clock us usually 24 deg)
How is the temp control for the cabin different
Temp selector sets master cabin reference not temp.
CAP controls the temp 6 deg either side of the master temp
usually at 12 O’clock (24) so CAP can control 18-29 deg
Where does the temp control for the Crew Rest compartment come from?
Zone D
(you can warm it with the electric heater but cant cool it
What does the AIR COND RESET do
resets any air conditioning faults and attempts to restart to normal operation
What switch positions should be indication for normal operations of the air conditioning panel
AUTO, NORM, ON positions
What are the indications on the AIR Synopsis page
SYS - MFD, AIR
Green - running
White - off
Amber - Failed
Grey - signal is invalid
What is Pack operation during eng start?
CAC’s load shead to conserve power
This condition shuts off the packs
How long before the packs restart
2 min after the eng start sequence is initiated
Start immediately after the second eng is running
What do we have automatic operation of for the non normal air conditioning system
Fault detection
overheat protection
back up modes for failures
What happens internally with a failure of a Air cycle machine?
What is the indication?
Pack automatically shifts to standby cooling mode
bypasses the ACM (T1, T2, Compressor)
indication:
Stby Cooling on synoptic
pack mode L and pack mode R - EICAS
Describe the Alternate Ventilation System (AVS)
provides ventilation to the cabin and flight deck if both packs are inop
indicates on Synoptic
VENTILATION - EICAS
When does the E/E cooling fans automatically switch to OVRD
both supply fans fail flow sensors fail low air flow detected excessive temp Smoke Fire switch is armed
Similar for both FWD and AFT
What can you use to aid in evacuating smoke form the cabin or flight deck
equipment cooling to OVRD
FWD - FLT Deck
AFT - Cabin
On the ground what tells the Grd Crew that equipment cooling has failed
Horn in the front wheel well
How can you remove power to the Miscellaneous equip
IFE/PASS
SEATS
switch on the Elec Panel
What is the fluid operation temperature for the PECS liquid cooling system
29 deg
When does PECS operate
when and engine, APU, or BOTH FWD external power sources are providing power
if only a single ext source is available only one PECS Loop operates
Where is PECS indication available
SYS
STAT
under LIQUID COOLING
How long do you have to have PECS liquid cooling operate after a flight?
both FWD Ext sources 10 min
1 - FWD Ext source 22 min
(this allows for the dissipation of residual heat)
Where are the Cargo Temp control
just above the Air Conditioning panel
What is the danger of an overheat protection of the FWD/AFT cargo
if automatic overheat shutdown occurs the cargo heat cannot be restored
Brrrrr
What has happened if you see OFF in yellow on the FWD cargo temp switch and CARGO HEAT FWD on EICAS
FWD Equip Cooling sys OVRD
FWD Equip Cooling sys exhaust fan inop
FWD cargo FIRE
