AS 411 EXAM 3 QUESTIONS & ANSWERS
What are the 3 hydraulic systems? - Answers -A, B, Standby
When is the standby hydraulic system used? - Answers -hydraulic pressure is lost in
both A and B systems
What 8 things does the hydraulic system power in the 737NG? - Answers -flight
controls, leading edge flaps/slats, trailing edge flaps, landing gear, wheel brakes, nose
wheel steering, thrust reversers, autopilot
Can both A and B systems power all flight controls without a loss in controllability? -
Answers -Yes
how many hydraulic fluid reservoirs are there and where are they located? - Answers -2
total (1 for A and 1 for B)
in the main gear wheel well
How are the hydraulic reservoirs pressurized? - Answers -bleed air
which hydraulic reservoir is the standby system connected to? - Answers -B
How many hydraulic pumps are there that can provide 3000 psi? - Answers -5
1 engine driven and 1 electric per system (4)
1 standby
how much more fluid volume does the engine driven pump supply compared to the AC
electric pump? - Answers -4 times more
What happens to the system when an engine driven pump is turned off? - Answers -
isolates fluid flow from the system components
the engine driven pump continues to rotate if the engine is on
What happens to the hydraulic system when the engine fire switch is pulled? - Answers
-shuts off fluid flow to the engine driven pump and deactivates the LOW pressure light
What switches relate to the A and B systems? - Answers -A: ENG 1, ELEC 2
B: ENG 2, ELEC 1
, What happens if an overheat is detected in either electric pump? - Answers -
OVERHEAT light
LOW PRESSURE light
power is removed from the pump
What may happen if the system A engine pump is lost and a heavy load is placed on
the A electric pump? - Answers -pump LOW PRESSURE light
A flight controls LOW PRESSURE
Master Caution, FLT CONT, and HYD annunciator
What cools and lubricates the pumps? - Answers -hydraulic fluid
What is used to cool hydraulic fluid? - Answers -heat exchanger
fluid goes through heat exchanger before going back into the reservoir
where are the heat exchangers located? - Answers -in the fuel tanks
What is the minimum fuel you can have in order to operate the electric driven pumps? -
Answers -1675 lbs
(in the related tank, not total)
if electric or engine driven pump pressure is low what sends the signal to illuminate the
LOW PRESSURE light? - Answers -pressure switches inside of the pumps
check valve in related valve isolates the pump
pressure transmitter sends the combined pressure of engine driven and electric pumps
to the indication system
if there is a leak in system A engine driven pipes or its lines what happens? - Answers -
there is a standpipe in the reservoir that prevents total fluid lose
the electric pump will maintain system A pressure
what happens if the engine driven and electric pumps in system A have leaks? -
Answers -the system slowly decreases to 0 fluid and pressure is lost
how much fluid does the standpipe preserve in the system A reservoir? - Answers -
20% full
What are the 3 hydraulic systems? - Answers -A, B, Standby
When is the standby hydraulic system used? - Answers -hydraulic pressure is lost in
both A and B systems
What 8 things does the hydraulic system power in the 737NG? - Answers -flight
controls, leading edge flaps/slats, trailing edge flaps, landing gear, wheel brakes, nose
wheel steering, thrust reversers, autopilot
Can both A and B systems power all flight controls without a loss in controllability? -
Answers -Yes
how many hydraulic fluid reservoirs are there and where are they located? - Answers -2
total (1 for A and 1 for B)
in the main gear wheel well
How are the hydraulic reservoirs pressurized? - Answers -bleed air
which hydraulic reservoir is the standby system connected to? - Answers -B
How many hydraulic pumps are there that can provide 3000 psi? - Answers -5
1 engine driven and 1 electric per system (4)
1 standby
how much more fluid volume does the engine driven pump supply compared to the AC
electric pump? - Answers -4 times more
What happens to the system when an engine driven pump is turned off? - Answers -
isolates fluid flow from the system components
the engine driven pump continues to rotate if the engine is on
What happens to the hydraulic system when the engine fire switch is pulled? - Answers
-shuts off fluid flow to the engine driven pump and deactivates the LOW pressure light
What switches relate to the A and B systems? - Answers -A: ENG 1, ELEC 2
B: ENG 2, ELEC 1
, What happens if an overheat is detected in either electric pump? - Answers -
OVERHEAT light
LOW PRESSURE light
power is removed from the pump
What may happen if the system A engine pump is lost and a heavy load is placed on
the A electric pump? - Answers -pump LOW PRESSURE light
A flight controls LOW PRESSURE
Master Caution, FLT CONT, and HYD annunciator
What cools and lubricates the pumps? - Answers -hydraulic fluid
What is used to cool hydraulic fluid? - Answers -heat exchanger
fluid goes through heat exchanger before going back into the reservoir
where are the heat exchangers located? - Answers -in the fuel tanks
What is the minimum fuel you can have in order to operate the electric driven pumps? -
Answers -1675 lbs
(in the related tank, not total)
if electric or engine driven pump pressure is low what sends the signal to illuminate the
LOW PRESSURE light? - Answers -pressure switches inside of the pumps
check valve in related valve isolates the pump
pressure transmitter sends the combined pressure of engine driven and electric pumps
to the indication system
if there is a leak in system A engine driven pipes or its lines what happens? - Answers -
there is a standpipe in the reservoir that prevents total fluid lose
the electric pump will maintain system A pressure
what happens if the engine driven and electric pumps in system A have leaks? -
Answers -the system slowly decreases to 0 fluid and pressure is lost
how much fluid does the standpipe preserve in the system A reservoir? - Answers -
20% full
