Hydraulics Flashcards
How many hydraulic systems are there?
3
What are they called?
A, B, Standby
What is the normal hydraulic pressure range?
3000 psi +/- 200 psi, 3500 max
What is the purpose of the PTU? When would it operate?
Provide B Hyd fluid for Autoslats and Leading Edge Devices (LED) When commanded by PTU Control
Valve In the event B Hyd pump pressure drops
Are there flight indications of PTU operation?
No
What are components specific to the Hydraulic System A?
Ailerons, Rudder, Elevator, Elevator Feel, Flight Spoilers (Two on Each Wing), Ground Spoilers, Alt
Brakes, No. 1 Thrust Reverser, Autopilot A, Normal NWS, Landing Gear, PTU
What are components specific to the Hydraulic System B?
Ailerons, Rudder, Elevator, Elevator Feel, Flight Spoilers (Two on Each Wing), LEDS, Brakes, No. 2
Thrust Reverser, Autopilot B, Alternate NWS, Landing Gear Transfer Unit (LGTU), Autoslats, Yaw
Damper, Trailing Edge Flaps
What does positioning a FLT CONTROL switch to STBY RUD do?
Manually activates the Standby Hydraulic Pump
What is the light logic when positioning a FLT CONTROL switch to STBY RUD?
STBY RUD ON, arms stby low press lgt, extinguish FLT ctrl low press lgt
What would cause the automatic operation of the Standby Hydraulic System?
a. Loss of sys A or B in flt, Flaps extended, respective FLT CONTROL switch positioned to ON.
b. Or the main PCU Force Flight Monitor (FFM) trips
During normal operations, what could cause variations in hydraulic quantity indications?
a. System A: Retraction gear may result in up to a 20% drop, System B: Extension of LED’s may result in
up to 20%
b. Cold Soaking: additional quantity drop of 5 to 10% up to 20%
What would indicate a hydraulic system requires a refill? When would you see this annunciation, and where is it
located?
A Refill (RF) on lower DU when quantity is below 75% or less, on gnd after shutdown or taxi in flaps up
What pressurizes the Hydraulic System A & B reservoirs?
Regulated bleed air
Which hydraulic reservoirs have a standpipe?
A & B
What quantity percentage do the associated standpipe(s) protect the reservoir(s) down to?
A: 20% /B: zero
enough for the PTU to fuction
With zero indicated on the Hydraulic System B quantity indicator, can the PTU still operate?
Yes
When is the Standby HYD LOW QUANTITY (amber) light armed? When would it illuminate?
Always, When standby reservoir is approximately half empty
What does a LOW PRESSURE (amber) light indicate? OVERHEAT (amber) light?
Respective HYD pump low press, Respective electric pump overheat
Does the Hydraulic System A reservoir standpipe protect against a leak in both the engine driven pump and
electric motor-driven pump?
No, protects against leak in Eng driven pump allowing operation of elec motor
System B?
No, (Provides enough fluid for PTU operation)
. What indications, if any, would you see in the event of a Standby Hydraulic system leak? Does it affect any other
system?
System B Hyd qty drop to approx. 72%
Should both ELEC hydraulic pump switches be turned on simultaneously?
No this could overload the system
What happens when you place a Flt Control Switch to STBY RUD?
a. Activates STBY Hydraulic Pump
b. Opens STBY Rudder shutoff valve
c. Powers STBY Rudder PCU
d. Extinguishes Low Press light
e. Illuminates STBY Rud on
f. Arms STBY Low press light
