Flight Controls System Ch. 9 Flashcards
What does the flight control system consist of?
Primary flight controls, secondary flight controls, multifunction spoilers (MFS), elevator & rudder
What controls are hydraulically actuated?
The MFS, elevator and rudder
What are the secondary flight controls? How are they actuated?
Flaps, speed brakes, ground spoilers
Hydraulically
Which of the primary flight controls are fly by wire?
The multifunction spoilers, and the rudder
Which aileron has a trim tab?
Left
Are any of the secondary flight controls fly by wire?
Yes, the spoilers
What does the stall protection system consist of?
Stick shaker
Stick pusher
AOA Indications
Aural warnings
Autopilot disconnect
Auto ignition
What is the stick pusher function provided by?
Autopilot pitch servo
What is the purpose of the FCECU?
Command/monitor flight controls
How many FCECU’s are there?
2
What is the MCU?
Motor Control Unit
Two channel motor the interfaces with the FCECU through dedicated wiring - one channel controls HSTA (Horizontal Stabilizer Trim Actuator) motor A and the other to motor B
How many channels do the FCECU’s have? What are they?
Two - Normal & emergency
How many multifunction spoilers are there?
4
How are the multifunction spoiler actuators operated?
Electrically operated hydraulic servo actuators
What kind of valve does the MFSA incorporate?
An integral hold down check valve
How many functions does the integral hold down check valve have? What are they?
3: Normal, Checked, and Relief
In the normal mode, how does the integral hold down check valve operate?
Sufficient hydraulic pressure allows the valve to free float, providing fluid to extend or retract side of the actuator as required
In the checked mode, how does the integral hold down check valve operate?
When the system senses insufficient pressure from the hydraulic system the valve will prevent actuator operation which prevents spoiler float
In the relief mode, how does the integral hold down check valve operate?
If system pressure exceeds 3,600 psi, an over pressure relief is built in to release pressure to prevent damage in the case of thermal expansion
How are each sides of the elevator connected to each other?
Through the force disconnect unit
What provides elevator position to the synoptic pages on the DU?
FCECU
If hydraulic pressure is lost, how can the elevators be controlled?
Manual reversion
What is the purpose of the eddy current damper?
Dampen the high rate of force applied to un-jam the control loop developed due to the abrupt release of the force disconnect unit
What is the Q-Feel Actuator?
Provides increased column feel forces at higher airspeeds by changing the length of the feel spring in line with the control column to the elevator actuator linkage
What is the Q Feel controlled by?
Electrically by FCECU 2, hydraulically by the right hydraulic system
What does the force disconnect unit do?
Allows for independent control of each elevator surface
When disconnected, commands from pilots side will command Left elevator. Commands from copilots side will command right elevator.
What is lost if the right elevator control loop is jammed?
Stick pusher, Q Feel, Autopilot
What are the type of flaps?
Fowler flaps
When would the FCECU stop flap motion?
Flap asymmetry of 3 degrees
How long does it take flaps to go from 0 - 39 degrees?
27 seconds
What does the alternate flap switch do?
Engages the alternate mode that provides a secondary method for controlling the flaps and the event of a flat lever RVDT failure, a failure in the normal channel command path, or a failure in the normal channel monitor path
How many panels do the spoilers have?
6 (3 per wing)
What do the innermost spoiler panels on the wings function as? What do the remaining two function as?
Ground spoiler only
Multifunction spoiler
What commands the roll assist function of the multi function spoiler?
The FCECU 2
What is available to provide an alternate means of roll control when a there is an aileron jam?
The aileron disconnect handle on the yoke
How does the (ADU) aileron disconnect unit operate?
Disengage is the pilot yoke from the mechanical linkage, once it is able to turn freely, the rotation will continue to cause the RVDTs on the pilots wheel to generate roll commands
What are the two levels of stall protection?
Stick shaker and stick pusher
How does the stall protection system work?
1st phase - SPS commands auto pilot and auto throttles to disengage, initiate auto ignition, and activates the stick shakers
If no corrective action is taken and the angle of attack increases to critical AOA, the 2nd phase is activated - Stick Pusher.
Stick pusher can be turned off by selecting the stick pusher button on the center pedestal to OFF, or the AFCS DISCON bar to OFF
