Hydraulic System Flashcards
When is STBY HYD low pressure light armed?
When does it illuminate?
Only when standby pump operation has been selected or automatic standby function is activated.
illluminates at appx 50%
If the Standby system has a leak what will happen?
- low quantity light on STANDBY HYD panel illuminates
2. B hydraulic reservoir will draw down to 64% full
What are the components of the RSEP (Rudder System Enhancement Program)
Separate input rods, control valves and actuators;
One for system A
One for system B
Standby PCU is controlled by a separate rod and control valve powered by the Standby Hydraulic System.
when does RPR provide full system pressure to the rudder PCU?
- takeoff below 1000 ft
- approach below 700 ft
- difference of >45% N1 between engines
- Hyd system B lost
When will the FFM automatically turn on the Standby Hyd pump?
If either Hyd system, input rod, or control valve has jammed or failed and the condition is detected for more than 5 seconds.
When does Stdby Hyd sys initiate automatic operation?
- loss of A or B system
- RPR fails in lo pressure mode and:
1. flaps extended
2. airborne, or wheel spin greater than 60 kts
3. FLT CONTROL A/B hyd sys ON
What happens when STBY RUD goes into automatic operation?
- Opens standby rudder shutoff valve
- activates STBY electric motor driven pump
- Allows STBY sys to power rudder and reversers
- illuminates STBY RUD ON / Master Caution / and FLT CONT lights
Positioning either FLT CONTROL switch to STBY RUD will:
- activate stby electric motor pump
- shut off related hyd sys pressure to ailerons, elevators, rudder by closing flight control shutoff valve
- opens standby rudder shutoff valve
- deactivates related LOW PRESSURE light when stby rudder shutoff vaalve opens
- allows stby system to power rudder alternate LE devices and thrust reversers (RAT)
- illuminates STBY RUD ON, Master Caution, and FLT CONT lights
Positioning either FLT CONT switch to STBY RUD
“SOAPY”
“SOAPY”
- STANDBY electric motor pump on
- OPENS opens standby rudder shutoff valve (think also closes FEAR Group)
- ARMS STBY LOW PRESS light
- POSITION LIGHT deactivated related LOW PRESSURE light when stby rudder shutoff valve opens
- YAW DAMP disengages (B SYS only)
What happens when you place the ALT FLAPS master switch to ARM?
“SAAB”
“SAAB”
- Standby hyd pump activates
- ARMS Stby low press light
- ARMS ALT FLAPS position switch
- BYPASSES hydraulics to trailing edge flap bypass valve
What happens when you move the ALT FLAPS switch to down?
- Fully extends LE devices using STBY HYD power
2. If held down electrically extends the TE flaps until released.
What causes FEEL DIFF PRESS light to illuminate?
Either HYD sys fails or elevator feel pitot sys fails.
Light is armed when TE flaps are up.
What causes SPEED TRIM FAIL light to illuminate
Failure in the speed trim system or, failure of a single FCC channel if SPEED TRIM FAIL light illuminates when recall is activated and extinguishes when reset.
What does SPEED TRIM accomplish?
Improves flight characteristics during operations with low gross weight, aft CG and high thrust when A/P is off.
Also monitors inputs of stabilizer position, thrust lever position, airspeed, and VS, then trims the stabilizer using the autopilot stabilizer trim. It operates most frequently during takeoffs and go arounds.
What are conditions for speed trim operation?
Flaps up or down N1 above 60% Autopilot OFF Airspeed between 100-300 kts 10 seconds after takeoff 5 seconds following release of trim switches sensing of trim requirement
What causes MACH TRIM light to illuminate?
Failure in the mach trim system or, failure of a single FCC channel if MACH TRIM FAIL light illuminates when recall is activated and extinguishes when reset.
What does MACH TRIM accomplish?
Provides speed stability above mach .615 by adjusting elevators through mach trim actuator.
What causes AUTO SLAT FAIL light to illuminate?
Failure of both AUTO SLAT computers or, failure of a single AUTO SLAT computer if light illuminates when recall is activated and extinguishes when reset.
What does autoslat operation accomplish?
With TE flaps set at 1-5 and the LEin the extend position, aa the airplane approaches stall angle, the slats automatically drive to full extend position, prior to stick shaker. It enhances stall characteristics at high AOA during takeoff, or approach to landing.
What is on HYD A system?
A REAL GIANT P
A/P A / Rudder / Elevator / Ailerons / Landing Gear
Ground Spoilers / Inboard fight spoilers / Alternate Brakes / Nose wheel steering / Thrust reverser / PTU
What is on HYD B system?
A REAL TOY BAAT L
A/P B
Rudder / Elevator / Aileron / Leading Edge devices
Trailing edge flaps / Outboard flight spoilers / Yaw Damper
Brakes (normal) / Alternate nose wheel steering / Auto slats / Thrust reverser / Landing gear transfer valve
HYD systems common to both A & B
FEAR Group
Feel / Elevators / Ailerons / Rudder / Gear
HYD Fluid heat exchanger located where?
Main Tank #1 for sys A & main tank #2 for sys B
Power Transfer Unit
Supplies additional VOLUME to operate autoslats and LE devices at a normal rate when system B engine driven pump is lost. PTU uses A sys pressure to to power a hydraulic motor driven pump to pressurize system B
When does PTU operate automatically?
+ airborne
+ system B EDP hyd pressure drops below limits
+ flaps less than 15 but not up
Landing Gear Transfer Unit
Supplies pressurized HYD fluid to raise the landing gear at a normal rate when system A is lost due to #1 engine loss.
When does Landing Gear Transfer Unit operate?
Airborne
#1 engine RPM drops below certain limit
LANDING GEAR lever is up
either main landing gear is not up and locked
