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