Chapter 13 - Hydraulics Flashcards
Hydraulic Pumps
Engine Driven Pumps - EDP
4 Seperate pumps each providing 3000psi
Demand Pumps - DP
4 Seperate pumps automatically operate during periods of high demand or if the EDP fails.
DP #1 & #4 are pneumatically powered
DP #2 & #3 are electrically powered
AUX - AP
Electrically powered on system 4 for use on the ground to power the brakes.
SYS FAULT light
Low Pressure
Low Fluid Quantity
High Fluid Temperature
NOTE - FAULT light for Sys.4 will go out when AUX pump is turned on however the PRESS light will remain illuminated.
Demand Pump PRESS light
DP selector is OFF or AUX
DP output pressure is low
DP failed
Demand Pump selector knob
AUTO
- DP operates when respective EDP output pressure is low
- Fuel Control Switch is placed to cutoff
- Engine Fire Handle is pulled
- DP #1 & #4 also operate when flaps are in transit on ground or when flaps are out of up inflight
AUX (System 4)
- Operates on ground until related EDP pressurizes system
- Respective DP push switch is off
- Does NOT turn off when EDP pressurizes system
EDP Switch
(Push Switch)
ON - EDP pressurizes system
No Light - OFF
PRESS - Low EDP pressure
Hydraulic Quantity
Hydraulic Pressure
Hydraulic Temperature
All 3 display on the STAT page on the DSP
QUANTITY
Displays as a percentage of full - 1.00 full
RF [ReFill] will display on ground when at or below 0.75
LO will appear on ground and inflight at 0.34
PRESSURE
Displays in PSI
TEMPERATURE
Temperature in ºC
Reservoirs
Independent reservoirs supply fluid to each hydraulic system. The bleed air system pressurizes the reservoirs to prevent pump cavitation and ensure positive flow during high demand conditions.
Brake Accumulator Panel
Hydraulic Pressure for the Brakes come from System 4
BRAKE SOURCE Light - All brake sources have low pressure
HYD BRAKE PRESS Guage - Brake Accumulator Pressure
System 1 Powers?
Inboard Trailing Edge Flaps
Body Gear Actuation
Nose Gear Actuation
Body Gear Steering
Nose Gear Steering
Alternate Brakes
Left Outboard Elevator
Left Inboard Elevator
Left Outboard Aileron
Left Inboard Aileron
Upper Rudder
Center Autopilot
System 2 Powers?
Alternate Brakes
Stabilizer Trim
Elevator Feel
Lower Yaw Damper
Right Autopilot
Spoilers 2, 3, 10 & 11
System 3 Powers?
Stabilizer Trim
Elevator Feel
Upper Yaw Damper
Left Autopilot
Spoilers 1, 4, 9 & 12
System 4 Powers?
Outboard TE Flaps
Wing Gear Brakes
Normal Brakes
Spoilers 5, 6, 7 & 8
Minimum in-flight speed with a failed engine where windmilling engine provides hydraulic power
160 KIAS
What is the normal source for the brakes?
System 4
If pressure is lost on System 4 will the BRAKE SOURCE light illuminate?
NO
If system 2 and/or 1 have sufficient pressure and automatic switching to alternate brakes
occurs, the light will not illumintate.
System 4, 1 and 2 must be low.
When do the demand pumps come on without a loss of pressure from the EDPs?
Inflight
- Flaps out of up
On the ground
- Flaps are in transit