Hydraulic and Flight Controls Flashcards
EDP
Engine Driven Pump
ACMP
AC Motor Pump
Do all systems have an EDP and an ACMP?
No, only systems 1 and 2; system 3 has 2 ACMPs
What kind of pump is 1B and what powers it?
It’s an ACMP and AC BUS 2.
The EDP for system 1 is powered by what?
The left engine.
Which hydraulic reservoir is the largest?
System 3 because it services the largest demand
What is the purpose of the three accumulators in the hydraulic systems?
They help maintain a constant pressure by smoothing transient demands.
When a hydraulic SOV is closed using the L/R ENG FIRE PUSH Switchlight ____________.
The affected system can still be pressurized by a backup pressure source.
When the L HYD SOV Switchlight is pressed this advisory message is generated:
HYD SOV 1 CLSD
The EDPs normally deliver hydraulic fluid at ______ +/- _______ psi to the system’s associated hydraulically-powered systems.
3,000/200
The AC powered pumps in the hydraulic system include:
2 in system 3 1 in system 1 1 in system 2
While in the AUTO position ACMP 3B will operate automatically when an IDG is operating and:
- Flaps greater than the 0 degree position 2. An IDG is on line.
How is hydraulic system No. 3 fluid cooled?
Radiantly through fuel tanks
Which pump is primary, which pump is secondary in each system?
(A) pump = primary (B) pump = secondary
Which hydraulic system has 2 ACMPs?
3
Where are the Hydraulic shutoff valves and how many?
2; 1 in system 1, the other in system 2. They are located upstream of each EDP to prevent hydraulic fluid from reaching an engine that caught on fire.
Do the ACMPs automatically start during or after an engine failure?
Neither, they don’t automatically start.
How are the flight control surfaces controlled?
Mechanically transmitted inputs via cables and pushrods to power control units, which hydraulically position the control surfaces.
What are the primary flight controls?
Aileron, elevator, and rudder
What are the secondary flight controls?
Slats, flaps and spoiler, aileron, rudder, and horizontal stabilizer trim.
PCU
Pressure Control Units
SFECU
Slat/flap electronic control units
Purpose of SFECUs?
Controls the operation of the slats and flaps.
SSCU
Spoiler Stabilizer Control Unit
What is the purpose of the SSCUs?
Provides automatic control of spoilers, horizontal stabilizer trim, pitch feel control and the rudder travel limiter.
How many SFECUs and SSCUs?
2 of each
How many channels are the SSCUs?
Dual
What is the purpose of the artificial feel units?
Mounted on primary flight controls to help prevent excessive flight control inputs.
What’s the purpose of the flight control disconnect mechanisms?
Mounted on aileron and rudder to allow the captain or first officer to maintain aircraft control in event of a flight control jam.
To prevent agains aileron flutter in the event of hydraulic failure, what is installed?
A flutter damper by the ailerons
When and how do the spoilerons activate?
At lower airspeeds, commanded by the SSCUs which receive electrical signal from the control wheel.
Where is the autopilot roll control servo?
Only on the right aileron
Describe the aileron and spoiler on control system.
2 separate circuits, Left controlled by captain, the right by first officer. Interconnected through torque tube mechanism, which allows them to operate in conjunction with inputs.
If a jam occurs that affects roll control, what can we do?
Disconnect the torque tube by pulling and rotating the ROLL DISC handle on center pedestal
With the ROLL DISC handle pulled, how are the flight controls changed?
Each side will operate it’s own side aileron, but the opposite side spoileron.
What does pressing the ROLL SEL PLT ROLL Switchlight do and when do we press it?
Pressed when we discover which side is operable. It enables the operable sides spoilerons to be used in conjunction.
When will the white flutter damper outline appear on the FLIGHT CONTROLS synoptic page?
If low hydraulic fluid is detected in the respective aileron flutter damper.
How much hydraulic power is necessary for aileron trim to operate?
From at least one system
How many PCUs per rudder?
3, 1 from each system
How many circuits in the elevator control system and what controls what?
2 systems, Captain controls left, First officer controls right.
Are the two elevator control circuits normally interconnected? If so, through what?
Yes, through a pitch disconnect mechanism.
What should we do in the event of an elevator control jam?
Separate the left and right circuits by pulling the PITCH DISC handle and turning it 90 degrees
What side of the elevator is the autopilot connected to?
The left circuit
With the PITCH DISC handle pulled and turned, what controls the elevator?
The operable side
How is pitch trim achieved?
By adjusting the angle of incidence of the HSTAB
How is the H-STAB repositioned?
By a screw jack driven by two electric motors controlled by the SSCUs
When the autopilot is engaged, stabilizer trim is controlled ______.
Automatically
How many trim channels are there and what do they control?
2 trim channels, each one moves a separate motor that moves the screw jack up or down to change the H-STAB angle of incidence.
What does the clacker mean and when does it come on?
Runaway trim condition, comes on if trim is active for more than 3 seconds with autopilot engaged. Amber “E” will pop on PFD. Bakes on the trim motor will prevent further trim displacement.
What must be operable for Mach trim to function?
- Both SSCUs must be operable 2. At least 1 stabilizer channel
What does MACH Trim do?
Compensates for Mach Tuck’s pitch down tendency by automatically repositioning H-STAB as a function of the Mach number.
Will the Mach Trim activate when the autopilot is not engaged?
No
How are the rudder pedals moved?
Hydraulically powered by three PCUs and is mechanically controlled by rudder pedal inputs.
Are the rudder pedal circuits the same?
Yes, when rudder pedals will move simultaneously when operated from either pilot station.
What provides rudder centering?
Primary Feel Unit under first officer’s pedals
What is the purpose of the Secondary Feel Unit?
To make sure the rudder remains centered in the event of a control disconnect.
What happens if there is a rudder jam?
Rudder pedals will continue to work, but more pressure may need to be applied. This is due to anti-jam mechanisms
What is maximum rudder travel?
33 degrees
What is the Rudder Travel Limiter and it’s purpose?
Controlled by SSCUs. And reduces available rudder travel at higher airspeeds. From 33 degrees to 4 degrees
Purpose of Yaw Damp
Reduces yaw oscillations, thus preventing Dutch roll
How many Yaw Dampers?
2
How many yaw dampers need to be engaged for the autopilot system to operate?
1
How many Yaw Dampers will pushing the DISC on the Yaw Damp panel disengage?
Both
What will happen if both yaw dampers fail
- Autopilot disconnects 2. Caution appears 3. YD on PFD displays
How many slats and flaps
3 leading edge slats and 2 trailing edge flaps per wing
How are the flaps and slats controlled?
Through the SFECU and the SLATS/FLAPS lever.
What moves first during retraction, slats or flaps? Extension?
Retraction: Flaps Extension: Slats
What physically moves the slats/flaps
Dual power drive units using drive shafts, gearboxes and actuators.
If one power drive unit fails, what happens?
Slats/flaps operate at 1/2 speed, Status message
How will you know if an asymmetric flap or slat setting occurs?
Bar and position readout on synoptic page change to white and a status message appears
If the flap/slat outline on the synoptic page is purple, what does that mean?
Information is not available
What does the EMER FLAP switch do?
When positioned to DEPLOY, SFECUs override control lever selection and extend slats to 25 and flaps to 20
How many spoilers and where are they?
- Inboard/outboard multifunction spoilers Inboard/outboard ground spoilers Per wing
What do the multi-function spoilers provide?
- Aileron assisted roll control (spoileron) 2. Proportional lift dumping (flight spoilers) 3. Ground lift dumping (ground spoilers)
How are the spoilers controlled?
Via the SSCUs and hydraulically actuated by single power control unit.
Are spoilers connected to their counterpart on the other wing?
Yes, if hydraulic system failure, both would quit.
Once armed, the spoilers will automatically extend when what conditions exist:
Thrust levers are idle and at least 2 of the following: 1. L or R MLG weight on wheels switch 2. Wheel speed greater than 16 knots 3. RA<10’
If automatic extension of ground spoilers doesn’t occur, what can we do?
Select MAN ARM position to extend all spoilers
When will the spoilers automatically retract?
Thrust levers less than TOGA and wheel speed less than 45 ORRR. TOGA is selected for a go-around
What monitors aircraft parameters in order to compute a stall angle?
Stall Protection Computer (SPC)
What will happen when the aircraft reaches a high AOA?
- Red STALL light flash 2. Warbler tone 3. Stick shaker 4. Autopilot disengages 5. Continuous ignition activates
If the AOA continues to increase past stall warning, what will happen?
The stick pusher will activate
How long will holding the AP/SP DISC switch disengage the stick pusher for?
As long as the switch is held
What circuit is the stall protection system connected to?
The right elevator
Lateral control is achieved by:
Ailerons, multi-function spoilers
After pulling the ROLL DISC switch, pressing an illuminated ROLL SEL Switchlight will…?
- Illuminate ROLL Switchlight on operable side 2. Display advisory message 3. Enable on-side spoileron operation
Will moving the AIL TRIM switch disengage autopilot?
No
How can control be regained in the event of an elevator control jam?
Pulling and turning the PITCH DISC handle
What will happen if a slat or flap power drive unit fails?
- Status message 2. Indication changes to white 3. Affected system operates at half speed
What happens when the EMER FLAP switch is used:
- Slats extend to 25 degrees, flaps extend to 20 degrees below VFE 2. An advisory message appears on status page
What does “FLT SPLR DEPLOY” advisory message tell you?
Aircraft is above 300’ RA, flight spoiler is extended or the lever is not in the 0 position
On the HYD synoptic page, if you lose a hydraulic system, what will you lose, what will you keep?
Keep the top 3, loose everything else.
HYD B pumps will come on when?
- Switch is in auto 2. It’s bus is powered 3. Flaps are 8 or greater.
What kind of flaps on the CRJ 700?
Full Fowler double slotted flaps.
Which control surfaces are fly-by-wire, which are mechanically connected?
“Oilers” are fly-by-wire Primary Flight controls are mechanically connected.
SSCU
Stab Spoiler Control Unit
What is the only hydraulic system that touches all 3 flight controls?
No. 3
What are the all electric controls?
Flaps and slats, trim
SFECU
Slat flap electronic control unit
What does the Emer flap switch do?
Mimic what the flaps and slats would do if the flap handle was in 20.
How do you know if the aileron is in trim with the autopilot on?
The yoke is neutral.
What does the artificial feel unit do?
Gives you tactile feedback based on your airspeed
How are the flight controls gust locked?
Automatically when they are powered down via hydraulic power.
What is bungee breakout and what does it do?
In the event of a PCU runaway, opposite input will put stress on a tension regulator triggering bungee breakout. This will allow the good control yoke to gain both sides of multifunction spoilers. Occurs automatically.
What does the ROLL SEL Switchlight do?
Allows control of the onside multifunction spoilers
Difference between PCU runaway and control jam?
PCU runaway: the SSCU will automatically allow the multifunction spoilers be controlled by good side. control jam: you have to decide what is the good side
Upward moving ailerons should be coupled with ______ moving multifunction spoilers
Upward
Where does the aileron Trim get it’s power from?
DC Bus
How are the controls connected in the aileron and elevator cable runs?
Through a torque tube
When is a flutter damper required?
Only when all PCUs actuating the surface have failed.
Where are the flutter dampers?
One by each aileron
What side is the stick pusher on?
Right hand side.
What cable run is the autopilot servo on?
The left
If you have disconnected the aileron or elevator, can it be reconnected in flight?
Mechanically, yes Realistically no, because you disconnected it for a reason
Can you disconnect the rudder control?
No.
Before landing, do I have to disconnect the Yaw Dampers?
No, autopilot is not associated with them.
What commands the yaw dampers?
The flight control computers
YD1 is controlled by? And YD2?
YD 1 = FCC 1 YD 2 = FCC 2
Yawdamp 2 is powered by what bus?
DC Bus 2.
RTL
Rudder Travel Limiter
What does the RTL do?
The faster you go, the less travel it will afford the rudder in order to prevent excessive rudder loading
Does RTL limit travel of rudder pedals?
No, just the rudder itself
SSCU
Stab Spoiler Control Unit
Trim Priority:
- Pilot Trim 2. Copilot trim 3. Autopilot trim 4. Auto trim 5. Mach trim
What is the only way to disconnect stab trim?
Stab Trim DISC
Can you disconnect the Stab Trim by pushing the engage button on the center pedestal?
Nope. Only allows you to engage.
when does “trim in motion” alert come on?
3 Sec of motor movement.
When would you use the EMER flap switch?
If the flap handle brakes mechanically.
SFECU
Slat/flap electronic control units
How many SFECUs control the slats and flaps?
2
How many slat panels on each wing?
3
BUTE
Bent up trailing edge doors mounted on outboard flaps that are used to direct airflow over the leading edge vanes during flap extension
How many motors for the flap mechanism? The slat?
2; 2 one common gearbox
Where are the flap/slat brakes located?
Outboard part of the torque tube.
What color is the hydraulic fluid?
Purple
What is the purpose of the hydraulic accumulators and what PSI are they pressurized to?
Absorb “bumps” from using the hydraulic systems.
What PSI are the pressure reservoirs pressurized to?
55 psi
Which hydraulic system is used for the alternate gear extension?
System No. 2.
Why do we always single engine taxi using the right engine?
We have outboard brakes from system number 2.
When will the pressure relief valve dump fluid and where does it expel it to?
3600 PSI; the fluid ecology bottle
Where does the power for the hydraulic shutoff valve come from?
DC EMERG BUS
With the brake accumulators only, how many applications of brakes?
6
When will the brakes turn amber on the HYD synoptic page?
1200PSI
When is HYD HIGH TEMP illuminated?
96 degree or higher hydraulic temperature is detected.
Why ADG deploys, hydraulic pump 3B switch must be in ________ to be powered.
ANY POSITION
Where is the system 3 brake accumulator?
Nose compartment
FLT SPLR advisory
N1 is greater than 80% Less than 300’ AGL
To get all 4 spoiler panels up on either side you need…
All 3 hydraulic systems
SPOST 1
System Power-On Test - done after CPOST, tests integrity of SSCU
What will the stall protection system do during an impending stall.
1st. Turn on continuous ignition and open the operability valve 2nd. Activate stick shaker and kick AP off 3rd. Stick Pusher, Stall switchlight flashes and warbler.
SPOST 2
System Power-On Test 2, occurs after SPOST 1 on the 1. 50th flight cycle and 2. when all three hydraulic systems are powered and 3. both stab trim channels are engaged. may be indicated by Magenta indications of the spoilers on the synoptic page
CPOST
Computer Power On Self-Test. Done immediately on
What CAS messages should you typically see before takeoff?
3 green advisories: L/R Rev Takeoff config okay
Multifunction Spoilers (MFS) consists of _____ on each wing. The outboard MFS are referred to as the _______ and the inboard MFS are referred to as the _______.
2 spoilers Spoilerons Flight spoilers
Two Stabilizer control units _______ automatically control operation of the spoilers, ___________.
Horizontal stabilizer trim, pitch feel control and rudder travel limiting.
Accumulator pressure
1500PSI
Describe aileron control system.
- Two separate roll control systems - 1 on left, one on the right 2. Normally interconnected, but can be separated in case of control jam 3. Turning control wheel sends mechanical signal (cables and pulleys) to aileron hydraulic PCUs - 2 PCUs per Aileron 4. PCUs will provide gust lock protection on the ground. 5. Moving wheels also signals spoiler control units SSCU to control extension/retraction of MFS - 1 PCU on each MFS
Purpose and location of flutter dampers
Each aileron to prevent aileron control flutter when all hydraulic fluid is lost at the PCU during flight. Provide gust lock protection on the ground.
Pull the ROLL DISC does what?
Disconnects Torque Tube that interconnects the two aileron control surfaces. Right side controls right aileron and left MFS, Left side controls left aileron and right MFS.
Selecting the ROLL SEL switchlight will do what?
Provides the use of spoileron function of the on side MFS.
What connects the flight control systems for the aileron?
A torque tube
How many PCUs on the rudder?
3
In a situation of a jammed rudder control system, what will happeN?
Antijam protection will allow both pilot’s and copilot’s rudder pedals to keep working, but more pedal force will be required to move the rudder.
How is the rudder gust locked on the ground?
Trapped hydraulic fluid
Rudder travel limiter is controlled by:
The SSCUs which will limit from 33 degrees to 4 degrees either side of neutral as aircraft speed increases.
Purpose of yaw dampers
Improve aircrafts stability by damping out oscillations in yaw. Prevents Dutch roll
The YAW dampers are ________ of the autopilot system
Independent
What will happen to the autopilot if the YAW DAMPER fails?
If only 1 fails, nothing. If both fail, it will disconnect.
At least _____ yaw damper must be engaged for the autopilot to be able to engage.
1
What happens when the PITCH DISC handle is pulled?
The pilot controls the left rudder and the copilot controls the right rudder.
The multifunction and ground spoilers are operated ______, but controlled via ______.
Hydraulically Electrical signals generated by SSCUs.
Actuation of the aileron trim will result in _______. Actuation of the rudder trim will result in _______.
deflection of the control wheels. No change to rudder pedal deflection
What controls the horizontal stabilizer trim?
Spoiler stabilizer control units (SSCUs). 2 channels control 2 trim motors that move a jack screw that changes position of the H-STAB. Each trim motor has a brake in case of stab trim runway.
H-STAB Trim Priority
MAAM Manual Trim Autopilot Trim Auto Trim Mach Trim
What does auto trim do?
Occurs when flaps are moving between 0 and 20 in either direction. Automatically retries to compensate for aircraft pitching caused by flap movement.
Purpose of Mach trim
Adjusts H-STAB position to compensate for the tendency to pitch down at increasing Mach numbers. Disabled when autopilot engaged.
SSCU
Spoiler Stabilizer Control Unit
SFECU
Slat/Flap Electronic Control Units.
How many slat panels?
3 slat panels on each wing. Inboard is largest, outboard is smallest.
How are the slats moved?
Electronic motors mounted on a common slat gearbox, torque tubes and mechanical actuators.
How are the flaps moved?
Electronic motors mounted on a common flap gearbox, torque tubes and mechanical actuators.
How are the slats/flaps held in their commanded position?
Electronically activated brakes mounted on the PDUs and outer torque tubes.
What system powers slat/flap movement?
AC buses. In emergency, they will be powered to half speed.
Describe what happens when I move the flap lever position from 0 to 8.
SFECUs receive electronic command to move slats -> SFECUs command change in slat/flap position -> Brakes released -> electronic motors on PDU are energized -> Slats/flaps move -> position reached -> PDU motors de-energized -> brakes are applied.
The emergency flap switch is used in case of a…
Slats/flaps control lever failure.
The ______ receives input from the FLIGHT SPOILER control lever and commands the left and right MFS to operate symmetrically.
SSCU (Spoiler Stabilizer Control Unit)
How many SSCUs?
2
3 tests of SSCU
Computer Power-On Self-Test (CPOST) System power-on self-test 1 (SPOST 1) System power-on self-test 2 (SPOST 2)
CPOST occurs?
When AC electrical power is initially applied to the aircraft.
SPOST 1 occurs when?
Immediately after CPOST.
SPOST 2 occurs when?
After a successful SPOST 1, following every 50th flight cycle, initiated when all three hydraulic systems are pressurized and both stabilizer trim channels engaged.
SPS
Stall Protection System
Describe the progressive actions of the SPS
High AOA approached - CONT IGNITION AOA even further increased - Stick Shaker AOA still continues - Stick Pusher
How to disconnect stick pusher:
STALL PTCT PUSHER - OFF AP/SP DISC - OFF
