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94 Cards in this Set

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Where does APU bleed air enter the pneumatic manifold?
Left of the Isolation Valve
Where does the external pneumatic air enter the pneumatic manifold?
Right of the Isolation Valve
What are all the sources that provide air for the pneumatic system?
External air, APU, and 5th and 9th stage engine bleeds
An 800 aircraft has three air conditioning control zones. The temperature controllers are in
NORMAL and trim air is ON. The two packs will supply air at what temperature
A temperature for the zone requiring the most cooling.
What happens when an engine bleed switch is placed to ON?
If engine bleed air and electrical power are available, the valve opens
What does an illuminated engine BLEED TRIP OFF light indicate?
Excessive engine bleed air pressure or temperature caution, engine bleed valve closes
automatically
How is engine bleed air temperature regulated?
Controlled engine fan air circulates through a precooler
Air for starting the engines is supplied from __________.
The left or right pneumatic manifold
Which statements are correct regarding the pneumatic manifold pressure sensors?
AC powered; located in left & right pneumatic manifolds
What do the duct pressure pointers indicate when one pack valve switch is placed to OFF with
the APU providing bleed air and the isolation valve in AUTO?
APU bleed pressure shows on both pointers
What occurs when the APU bleed air switch is placed to ON?
DC power signals valve to open, APU bleed air opens the valve if RPM is above 95%
What is the power source for the pneumatic isolation valve?
AC power
Which statement best describes the isolation valve function?
Isolates left & right sides of the pneumatic manifold and is closed during normal operation
What action causes the pneumatic isolation valve to open when the switch is in the AUTO
position
Placing an engine bleed air switch or pack switch to OFF
What is the function of the DUAL BLEED light?
To warn when the APU may be back pressured by engine bleed air
Which valve and switch combination causes the DUAL BLEED light to come on?
APU bleed valve OPEN & right engine bleed switch ON, with the isolation valve OPEN
What is the crew action for an illuminated DUAL BLEED light prior to engine start?
No action. Dual Bleed Light is normal during engine start with APU bleed air
Which condition illuminates a WING-BODY OVERHEAT light?
All answers are correct

(Bleed air leak in the APU bleed air duct
Bleed air leak in the wing leading edge area inboard of the engine strut
Bleed air leak in the aircraft keel beam area)
Which duct pressure indication is acceptable for a 6-737-300 engine start at the Denver airport?
(5431 ft. above sea level)
28 psi
What engine stages provide bleed air?
The 5th and 9th stage
The 9th stage engine bleed air is the primary source of bleed air for pneumatics when the engine
is at cruise thrust.
False
The engine bleed valves are located:
Downstream of the 9th stage modulation/shutoff valve
How are the bleed valves operated?
They are electrically controlled and pneumatically operated
Excessive engine bleed air pressure or temperature will cause what condition to occur?
A bleed trip
If the APU bleed valve and switch are open, the valve will automatically close with APU
shutdown.
True
A right WING-BODY OVERHEAT light could indicate a bleed air leak in all of the following,
except:
In the keel beam area
What B-737-500 minimum duct pressure is required to operate two air conditioning packs from
one bleed source?
20 - 25 PSI
The potable water system pressurization line connects to which part of the pneumatic manifold?
The left side
The Engine Bleed Valve Trip pressure sensor is located __________.
Before bleed air reaches the engine bleed valve
The Engine Bleed Valve Trip temperature sensor is located
After the engine bleed air passes the engine bleed valve and pre-cooler
What limitation is imposed when the DUAL BLEED light is illuminated?
No more than idle engine power is allowed.
External pneumatic air can be used to start the number 1 engine __________.
If the isolation valve is open
The APU provides bleed air directly to
The left side of the pneumatic manifold
The engine bleed valve must be open for ENGINE anti-ice to be available
False
What is the normal source of conditioned air for the flight deck with both packs operating?
(300/500)
The left pack prior to the mix manifold
What is the indication on the respective AIR MIX VALVE position indicator when a pack valve
closes? (300/500/700)
Full COLD.
Which is correct for pack operation?
Bleed air flows through a heat exchanger, the ACM compressor, a second heat
exchanger, then the ACM turbine.
What does an illuminated PACK TRIP OFF light indicate? (8-737-300)
Pack valve closed by compressor discharge or turbine inlet overtemp or duct over temp.
When are the RAM DOOR FULL OPEN lights extinguished?
In cruise with low pack temperature
On the ground, what is the proper indication of the ram door position lights?
RAM DOOR FULL OPEN lights illuminated
What is the function of the turbofan in the ram air exit duct? (8-737-500)
Augments ram airflow when a pack is operating on the ground or inflight with the flaps not
up.
Which statement is correct regarding the air conditioning system deflector doors?
The doors extend on the ground to prevent FOD ingestion
What is the purpose of the recirculation fan?
Reduced pack air loads & engine bleed demand
Where is filtered RECIRC FAN air discharged?
Into the mix manifold.
What occurs when a pack switch is placed to the HIGH position with the other pack switch in
AUTO and the RECIRC FAN switch in AUTO? (737-300)
Respective pack goes to high flow & recirc fan shuts down.
Which statement is correct regarding single pack operation with one pack switch in AUTO and
one pack switch OFF inflight?
Remaining pack goes to high flow in flight when flaps are up.
With the RECIRC FAN switch at AUTO, and both pack switches at AUTO, which statement is
correct regarding the recirculation fan operation? (737-500)
Recirc fan shuts down when either pack switch is placed to HIGH
What does an illuminated DUCT OVERHEAT light indicate? (737-500)
Duct has overheated and mix valves have driven full COLD
How is hot air removed from the circuit breaker panels and the E & E compartment equipment?
By either the main or alternate equipment cooling fans
Which statement is correct regarding operation of the flow control valve? (737-500)
Closes when cabin pressure differential reaches 2.5 psid
What does an illuminated EQUIP COOLING OFF light indicate?
NO airflow from the respective equipment cooling fan.
How is the forward cargo compartment heated when cabin differential pressure is above 2.5 psi
with the forward outflow valve closed? (737-500)
The recirc fan maintains airflow around the outside of the compartment
Which systems are reset by means of the TRIP RESET switch? (737-500)
DUCT OVERHEAT, PACK TRIP OFF & BLEED TRIP OFF
How are the pack & isolation valve switches positioned for a BLEEDS-OFF takeoff?
Pack switches AUTO, isolation valve switch CLOSE
During a bleeds ON takeoff, the air conditioning pack switches and the isolation valve switch are
positioned
The right pack in AUTO, the isolation valve switch in AUTO, and the left pack in AUTO
Inflight, when both air conditioning packs are operating and the RECIRC FAN is in AUTO, placing
a pack switch to HIGH: (737-500)
All answers are correct

(Turns the RECIRC FAN off
Causes the pack to operate at a higher than normal rate of air flow
Causes the forward outflow valve to open
With both packs operating, if air conditioning smoke appears in the cockpit and in the cabin, the
most likely source is: (737-500)
Left air conditioning pack
With the RECIRC fan switch in AUTO, the fan __________. (737-500)
Operates if one pack is turned OFF and the other is in AUTO
E & E compartment cooling air flow is normally provided by the:
Equipment cooling fan
Overheat temperature sensors that will cause a pack trip are located in the: (737-500)
ACM compressor discharge duct, turbine inlet duct, and supply duct.
When parked at the gate, external conditioned air temperature __________ controlled by the
packs
IS not
Bleed air for the pack is __________ as it passes through the primary heat exchanger
Cooled
Each pack has a temperature selector. The selector on the left controls the temperature for the
__________. (737-300/500)
Flight deck
With the pack switch turned OFF, the pack valve closes and the mix valves __________. (737-
300/500)
Move to full cold
With the aircraft airborne, when is the forward outflow valve closed? (737-300/500)
When the recirculation fan is operating
Which cabin pressure control modes utilize the outflow valve DC motor? (non-digital controller)
STBY & MAN
When should the equipment cooling flow control valve close? (737-300/500)
At 2.50 psid
Which model 737 has a TRIM AIR switch on the overhead panel.
800 model
Which of the following 737 models has a Forward Outflow Valve?
500 model
What occurs when the FLT GRD switch is placed to FLT with the aircraft on the ground, packs
ON, doors CLOSED, and engine bleed air available? (737-300/500)
The main outflow valve modulates as necessary to maintain the aircraft at 200 feet below
departure field elevation
If the aircraft climbs above the altitude set in the pressurization controller FLT ALT window, the
cabin pressure will remain constant until which psid? (737-300/500)
7.90 psid
The B-737-700 has pressure relief valves that limit the cabin differential pressure to what value?
9.1 psid differential
What altitude is set in the STANDBY CAB ALT indicator when operating in AUTO during the
receiving aircraft check?
200 feet below landing field elevation
What altitude is set in the STANDBY CAB ALT indicator during the receiving aircraft check when
operating the flight with the STANDBY pressurization system?(Auto system inop)
Takeoff field elevation minus 200 feet
What procedure is preferred for MANUAL control of pressurization? (737-300/500)
Use the MANUAL - CLOSE / OPEN switch & MAN DC for slower operation of the outflow
valve
What does an illuminated OFF SCHED DESCENT light indicate?
Aircraft descending without having reached the selected cruise altitude
What does an illuminated AUTO FAIL light and STANDBY light on the pressurization panel
indicate? (737-300/500)
Auto control has failed and automatically switched to STANDBY mode
Which condition illuminates the pressurization AUTO FAIL light? (737-300/500)
Cabin rate of change has exceeded + or - 1800 fpm
Which lights should come on when AC electrical power is lost to the AUTO pressure control
system? (non-digital system) (737-300/500)
AUTO FAIL & STANDBY
Which statement is correct regarding the outflow valve position indicator?
Operates in all pressurization modes with AC power available
What is the purpose of the pressurization flight/ground switch GND position? (737-300/500)
Drives main outflow valve full open on the ground
What occurs if the FLT / GRD switch is not selected to FLT for takeoff? (737-300/500)
The aircraft will pressurize after takeoff
All of the following items control the ram air system ram door and exhaust louvers except:
The pressurization controller
What is the maximum differential pressure allowed by the System Safety Pressure Relief Valves?
(737-300/500)
A differential pressure of 8.65
If the aircraft pressurization system is operating in AUTO on the ground, moving the FLT/GRD
switch from GRD to FLT will cause the aircraft to: (737-300/500)
Pressurize to approximately 200 ft. below field elevation
The forward outflow valve is closed when: (737-300/500)
The RECIRC FAN is operating
When is the RAM DOOR FULL OPEN light illuminated?
On the ground, or in flight with the flaps extended
Illumination of the amber pressurization OFF SCHED DESCENT light indicates what situation?
The airplane is descending prior to reaching the selected flight altitude
What is the maximum allowable differential pressure for takeoff?
.125 PSID
The air conditioning packs may be operated in HIGH during a bleeds on takeoff
False
With the aircraft at the maximum certified altitude and one pack operating, what is the lowest
cabin altitude can that be maintained?
8000 feet
Which of the following rely on pneumatics for operations?
Water tank pressurization
Which of the following 737 models has a forward outflow valve?
B737-500
Which B737 model has a trim air switch on the overhead panel?
B737-800