AIR CONDITIONING AND PRESSURIZATION Flashcards
When does the DUAL BLEED light illuminate?
Illuminated (amber) – APU bleed air valve open and engine No. 1 BLEED air
switch ON, or engine No. 2 BLEED air switch ON, APU bleed air valve and
isolation valve open
When in AUTO mode, when does the isolation valve automatically close?
Isolation valve closes automatically if both engine BLEED air switches are ON and both air conditioning PACK switches are AUTO or HIGH
When in AUTO mode, when does the isolation valve automatically open?
Isolation valve automatically opens if either engine BLEED air or air
conditioning PACK switch positioned OFF
What does the left wing body over heat light mean?
left light indicates overheat from bleed air duct leak in left engine strut, left
inboard wing leading edge, left air conditioning bay, keel beam or APU
bleed air duct
What does the right wing body overheat light mean?
right light indicates overheat from bleed air duct leak in right engine strut,
right inboard wing leading edge or right air conditioning bay
What does the bleed trip off light indicate?
Illuminated (amber) – excessive engine bleed air temperature, over-pressure or
under-pressure
— related engine bleed air valve closes automatically
— requires reset
OR
Illuminated (amber) – a failure within the bleed air system
— bleed system failure may not be resettable
OR
Illuminated (amber) – an incorrect bleed air configuration after takeoff or
go-around
— turning either BLEED switch ON will extinguish both BLEED lights if
lights illuminated because of a configuration problem
What does the bleed trip reset button do?
resets BLEED TRIP OFF, PACK or ZONE TEMP lights
— related engine bleed air valve opens, or related pack valve opens, or related
trim air modulating valve opens
Lights remain illuminated until reset
ZONE TEMP Lights Illuminated amber. What does it mean?
ZONE TEMP Lights Illuminated (amber):
— CONT CAB indicates a duct temperature overheat or failure of the
flightdeck primary and standby temperature control
— FWD CAB or AFT CAB indicates duct temperature overheat.
During a RECALL, what does the associated ZONE TEMP Lights illuminated amber mean?
CONT CAB indicates failure of the flightdeck primary or standby temperature control
FWD CAB or AFT CAB indicates failure of the associated zone temperature control
What happens to the associated trim air modulating valve when you turn a temperature selector knob to the off position?
Turns the associated trim air modulating valve off
With the pack switch in AUTO, what happens if you turn one pack switch off?
The other pack goes to high flow if the flaps are up
With the pack switch in AUTO, what happens if you are operating one pack with the apu and both engine bleed switches off?
The operating pack goes to high flow
In flight, does the right recirculating fan operate if both pack switches are in high?
No
In flight, does the left recirculating fan work if either pack switch is in high?
No
On the ground, the right recirculation fan operates even if both PACK switches are in
HIGH. True or False?
True
On the ground, the left recirculation fan operates unless both PACK switches are in HIGH. True or False?
True
What does a pack light indicate?
Both primary and standby pack controllers failed
Or
Pack trip off
Or
Incorrect pack configuration after takeoff
Or
Indicates failure of the Flow Control Valve to open when commanded on
During Master Caution recall, what does a pack light indicate?
During Master Caution recall, indicates failure of either primary or standby
pack control
What happens to the EQUIP SMOKE light after smoke is no longer detected?
Light extinguishes 30 seconds after smoke is no longer detected
When does the altitude warning horn sound?
Altitude warning horn sounds when cabin exceeds 10,000 feet altitude
What does it mean when the ALTERNATE light is illuminated along with the AUTO FAIL pressurization light?
Single pressurization controller failure
What does it mean when the AUTO FAIL pressurization light is illuminated alone?
Both pressurization controllers failed
What is the minimum and maximum selectable values in the Flight altitude selector on the pressurization panel?
-1000 to 42000 ft
What is the minimum and maximum landing field elevation you can select on the pressurization panel?
-1000 to 14000 ft
How many pack controllers does each pack have?
2 independent controllers
Which systems rely on bleed air for operation?
The following systems rely on the bleed air system for operation: — Air conditioning/pressurization — Wing and engine thermal anti-icing — Engine starting — Hydraulic reservoirs pressurization — Water tank pressurization — Aspirated TAT probe — Nitrogen generation system
Do we have a nitrogen generation system?
Yes
Which stages do we tap bleed air from?
5th and 9th - NG
Or
4th and 10th - MAX
How are the engine bleed valves operated?
Electro pneumatic
Are the engine bleed valves AC or DC powered?
DC
What normally causes a an engine bleed valve to trip off?
Over temperature or over pressure
On certain aircraft, what happens if you takeoff with incorrect bleed configuration?
45 seconds after flaps are retracted, both BLEED lights illuminate
On certain aircraft, what happens, if there is a fault in the bleed system?
Bleed valve trips off and the BLEED light illuminates
Is the bleed isolation valve AC or DC powered?
AC
Is the isolation valve position affected by the apu bleed valve position?
No
What happens to the apu bleed valve when the apu is shutdown?
Closes automatically even if the switch is open
Is the apu bleed valve AC or DC powered?
DC
Thrust must be limited to what with the DUAL BLEED light illuminated?
Idle to decrease the possibility of back pressuring
Which pack supplies the flight deck?
Left pack. However, excess air from left pack is rerouted to the mix manifold for use in the cabin.
Which pack supplies the cabin?
Right pack
How many recirculation fans do we have?
2
Should you operate both packs from a single engine bleed source?
No
Can the apu supply both packs in the air and on the ground?
No. Only on the ground
Where does preconditioned air enter the aircraft?
The mix manifold. It bypasses the packs. Packs should not be on while using pre conditioned air.
What is the function of the ram air system?
The ram air system provides cooling air for the heat exchangers. Operation of the
system is automatically controlled by the packs through operation of ram air inlet
doors
When is the ram air inlet door full open?
On the ground and in the air with flaps extended
What happens to the ram air inlet doors while aircraft is in the air with flaps retracted?
They modulate
When are the deflector doors closed?
They are closed while on the ground. They are open while in the air.
What happens to the pack valve when there is an over heat condition?
Closes
If a primary pack controller fails, what takes over?
The secondary controller in the opposite pack
What is the temperature selector range?
18c - 30c
What temperature does the pack controller maintain during single pack operations with the trim air off?
During single pack operation with the
TRIM AIR selected OFF, the pack attempts to produce an air temperature to satisfy the average temperature demands of all three zones.
What happens if air in a particular zone supply overheats?
The associated zone trim air modulating valve closes. You can reset it after the air cools down.
What does a ZONE TEMP light mean?
If air in a zone supply duct overheats, the associated amber ZONE TEMP light
illuminate
What happens if both the primary and backup controllers for both pack fails?
In the event of a dual failure of the IASCs resulting in both the primary and backup
controls becoming unavailable:
— Adjusting the Zone Temperature selectors will not change the temperature.
— The Pack Temperature Control valves and the three Zone Trim Air valves will
remain in the last commanded positions.
— The pack overheat protections will be functional and will automatically shut down
the Air Conditioning Pack if there is a pack overheat trip.
— If the control cabin (flightdeck) or passenger cabin becomes excessively hot or
cold, the flight crew should perform the Cabin Temp Hot or Cabin Temp Cold
non-normal checklist.
What happens if all temp selectors are positioned off?
If all Temperature Selectors are positioned OFF, the pack controls will
cause the left pack to maintain a fixed temperature of 75°F (24°C) and the right pack
to maintain 65°F (18°C) as measured at the pack temperature sensor.
Are the recirculation fans AC or DC?
AC
If an overtemperature occurs on the ground, alerting is provided through the crew
call horn in the nose wheel well. True or False?
True
How many fans does the equipment cooling supply duct have?
2
How many fans does the equipment cooling exhaust duct have?
2
What happens when smoke is detected in the E/E system?
When smoke is detected the system will automatically set the packs to high flow, turn the E/E Cooling Supply Fan(s) OFF for approximately 5 minutes, overboard exhaust valve opens to the smoke position and the recirculation fans turn off. The E/E Cooling Supply Fans return to normal operations 5 minutes after the first detection of smoke. If smoke is re-detected, the Supply Fans turn OFF for another 5 minutes.
Where does the forward cargo compartment get air from?
Recirculation system circulates the air from the cabin into the forward cargo compartment.
Where does the forward cargo compartment get additional heating from?
The E/E exhaust is routed into the forward cargo compartment anytime the overboard exhaust valve is closed.
What are the 3 modes of pressurization?
Auto, Alternate and manual
How many outflow valves do we have?
1
Which valve acts like an outflow valve to aid in controlling cabin pressure?
Overboard exhaust valve
The overboard exhaust valve is open while the aircraft is on the ground. True or False?
True
The outflow valve is normally open while aircraft is on the ground. True or False?
True
When does the pressurization controller start pressurizing the aircraft?
While on the takeoff roll. Pressurizes the aircraft to approximately 150 ft below takeoff field elevation.
How many pressurization controllers are there?
2
Are the motors that drive the outflow valve AC or DC powered?
DC
How many motors are associated with the pressurization system that can be used to control the outflow valve?
- One for Auto mode, one for Alternate mode and one for Manual mode
How many positive pressure relief valves are there?
2
How many negative pressure relief valves are there?
1
Maximum cabin altitude?
8000 ft at FL 410
Where does the aft cargo compartment get air from?
Passenger cabin air is drawn through foot level grills, down around the aft cargo compartment, where it provides heating, and is discharged overboard through the outflow valve
What happens if one of the auto pressurization controllers fail?
The alternate takes over
The two auto pressurization controllers alternate on every leg as the primary controller. True or False?
True
When is the cruise pressurization mode activated?
The cruise mode is activated when the airplane climbs to within 0.25 psi of the selected FLT ALT
When is the descend mode activated by the pressurization controller?
The descent mode is activated when the airplane descends 0.25 psi below the selected FLT ALT. The cabin begins a proportional descent to slightly below the selected LAND ALT
What happens if you divert back to the origin airport prior to reaching the selected cruise altitude with regard to the pressurization system?
The controller programs the cabin to land at the takeoff field elevation without further pilot inputs.
Does the manual control motor operate at a slower or faster rate than the 2 auto motors?
Faster. Full travel of the outflow valve only takes 20 seconds
The MAX can run both packs in the air with only one engine operating. True or False?
True
The NG can run only one pack in the air with only one engine operating. True or False?
True
Are all 3 motors that control the outflow valve AC or DC?
All are DC
