Flight Controls Flashcards
Primary flight controls are:
Ailerons, elevators, rudder
Secondary flight controls are:
MFS (Multi function spoilers), Slats/Flaps, trim
One ___ exists for every hydraulic system that power the flight control surface.
PCU
Following a complete hydraulic failure, what controls will still be available?
Slats/Flaps and stab trim
Which hydraulic system powers the inboard MFS (multi function spoilers) panels and how many PCU’s exist per panel?
HYD System 2
One PCU per panel
Which hydraulic system powers the outboard MFS panels and how many PCUs exist per panel?
HYD System 1
One PCU per panel
How are flaps/slats powered?
Electrically
Which flight control PCUs are actuated through direct linkage?
Elevator, Ailerons, Rudder use cable/pully system.
Which flight control PCUs are actuated through Fly-by-wire commands?
MFS
What is a PCU and what does it do?
Power Control Unit; hydraulically actuates flight control surfaces
Does a PCU require hydraulic power to actuate flight controls?
Yes
Why is there not a PCU runaway procedure for elevator or rudder?
The other PCUs will over power the failed PCU
From the pilot’s perspective, what will be different with an aileron jam than a PCU runaway?
Jam may not be noticed right away, controls are sluggish.
PCU runaway will be an uncommanded roll.
How can you isolate a jammed aileron/elevator
The roll or pitch disconnect handle will use the torsion tube disconnect.
What will occur 20 seconds after pulling the ROLL DISC handle?
SSCU (spoiler stabilizer control unit) illuminates both ROLL SEL lights on dash panels. Caution message will appear.
What occurs after pressing the PLT ROLL Switchlight?
Connects onside MFS to the side selected. (Previously only had opposite side MFS)
If you should inadvertently disconnect the ailerons/elevators in flight can they be reconnected?
Yes
Does moving the control column move the horizontal stabilizer?
No, moved by stab trim
When does the airplane automatically apply stabilizer trim?
When flaps are changed from 0-20 or 20-0 when hand flying it will use auto and mach trim.
What is the stabilizer trim priority?
CA, FO, Autopilot, Auto Trim, Auto Mach
How many PDUs (power drive units) exist for the flaps?
1 for flap (also 1 for slats)
What does the status message FLAPS HALFSPEED mean?
One channel or motor of SFECU (slat flap electronic control unit) is inop. Flaps still activate just at reduced speed.
What would result from an asymmetrical flap deployment/retraction?
FLAP FAIL caution message. Brake position sensor will stop movement when 5 degree difference or more is detected.
What type of flaps are on the CRJ?
Double slotted flaps
How many PDUs for the flaps?
2 PDUs
Audio clacker will sound when trim is engaged for more than __ seconds.
3 seconds
_____ prevents damage to ailerons when hydraulic pressure is not on or lost. This function is automatically built into the PCUs for the elevator.
Flutter damper
How many SSCU’s are there (Spoiler stabilizer control unit)
2
What senses slat/flap position?
BPSU (Brake position sensor unit) uses transmitters to stop slat movement when correct position is obtained.
What does it mean when flap position indicator is white?
Difference between L and R flap is 5 degrees or greater. Flaps are misconfigured.
What occurs when you move the EMER FLAP switch to the DEPLOY position?
Lowers slats/flaps to 25/20 on the CRJ-700 or 20/20 on the CRJ-900. SFECU will not allow flap overspeed. Can be reset to normal position if needed.
List all of the functions of the MFS (Multi function spoilers):
Roll augmentation at low speeds, flight spoilers to slow down, ground lift dump.
Which spoilers are the MFS (Multi function spoilers)?
2 OB are multifunction
2 IB are ground
What is the logic for when the ground spoilers will deploy on touchdown vs when the MFS spoilers will deploy on touchdown?
Multi function assist in roll control with crosswind landings and will not deploy right away.
What are the stall warnings/indications you would receive?
- Continuous ignition on
- Stick shaker + AP disconnect
- Aural warbler, red stall switchlight, stick pusher
Difference between FLT SPLR DEPLOY caution message and FLT SPLR DEPLOY advisory message?
Caution: when less than 300’ RA and in climb detent
Advisory: Greater than 300’ RA and below climb detent
What is the company limit on spoiler use?
1000’ AGL
At rotation the stick pusher malfunctions and inadvertently pushes, what would you do?
Hold AP/SP Disconnect button on yoke and if needed turn off STALL PTCT switch on either side.
What does the BUTE door do?
Bent Up Trailing Edge: directs air flow over leading edge vane during flap extension
How do you tell the difference between an inadvertent sick pusher and a nose down stab trim runaway?
Trim runaway clacker activates after 3 seconds. Stick pusher will be abrupt.
