Flight controls Flashcards
How many channels FBW has?
3 channels, Any of the three FBW channels can allow safe flight and landing.
What are Inceptor Interface Modules (IIMs),
The FBW system includes three IIMs. The IIMs receive data from the flight deck controls and transmit it to the PFCCs. Each IIM is connected to the three PFCCs.
How many PFCCs are there and which one is control?
3 PFCCs, only one is in control of FBW system, it is determined automatically during startup
What is function of REUs?
Transmit commands from PFCCs to hydraulic PCUs and to stabilizer trim motors
What is the AFCU
Alternate Flight Control Unit, bypasses the REUs if there is a severe FBW system degradation
Explain REU direct mode?
PFCUs recieve inputs from IIMs and REUs skipping PFCCs. It is REU DIRECT MODE
What is provided by Fly-by-wire Normal mode?
Envelope protection, structural envelope protection, ground mode functions
Explain nose gear loading function of the FBW system
With the sidestick at the neutral position (no pilot input), the elevator is automatically set to 12 degrees nose down up to 80 kt and decreases to 0 degrees by 90 kt.
Normal mode ground mode functions?
- Direct, full travel authority of the elevator,
- Pitch rate damping,
- Direct control of the horizontal stabilizer trim,
- Nose-up pitch attitude limit set to 17 degrees,
- Sidestick shaker function above 60 kt, and
- Yaw damper function enabled at 70 kt
What is pitch limit on ground in normal mode between 60 and 90kt?
Reducing from 12 to 0 degrees
At what altitudes is bank limited to half bank?
31500ft
What is maximum roll and bank provided by engine-out compensation function from Fly-by-wire?
5 deg yaw, 20 deg bank
Is engine out protection function working on ground?
NO
Wht types of direct modes are there?
Dependent on the type of failure, the system reverts to one of three types
of direct mode:
* Primary Flight Control Computer (PFCC) direct mode,
* Remote Electronics Unit (REU) direct mode, or
* Alternate Flight Control Unit (AFCU) direct mode.
What is PFCC direct mode?
The PFCC direct mode is used when the information required for normal mode is degraded or not received by the PFCCs
What are the 2 PFCC direct sub modes?
- When PFCC direct mode occurs because there of data input failure from all Air Data Smart Probes (ADSP), the FLT CTRL DIRECT ADS
caution message is displayed on the EICAS page. - When PFCC direct mode occurs because there is an input failure of all inertial data, the FLT CTRL DIRECT IRS caution message is
displayed on the EICAS page.
What is REU direct mode?
The REU direct mode is used when all the PFCCs have failed or all
signals to the REUs are lost. This mode has the same functionality as
PFCC direct mode, with the exceptions that follow:
* No selection of sidestick priority,
* Ground spoilers not available,
* No automatic ground lift dumping, the MFSs must be manually
deployed, and
* The pitch trim rate is a function of the slat/flap position, but is slower
than PFCC direct mode.
What is AFCU direct mode?
The AFCU direct mode is automatically selected when control
requirement is lost due to failure of multiple REUs. In this mode, the
AFCU interfaces directly with the flight deck controls and actuators. It
uses dedicated sensors and channels with no reliance on the REUs. The
AFCU direct mode provides an independent control path from the flight
deck controls directly to all primary surfaces.
The AFCU direct mode has the same functionality as the REU direct
mode, with the exceptions that follow:
* MFSs are not available,
* The rudder authority is set to single engine operation settings, and
* The pitch trim is like PFCC direct mode regardless of slat/flap
configuration.
When the AFCU direct mode is activated, a red DIRECT message is
displayed in the upper left corner of the PFD, and the FLT CTRL
DIRECT warning message is displayed on the EICAS page
When is aileron trim available?
Only on ground or Direct mode
How the MFS spoilers work in direct mode?
Deploy to 30 deg, whereas in normal mode deploy to 50 deg
When do MFSs are stowed automatically?
In high Alpha angles or thrust at angle above 24 degrees.
SPOILER MISMATCH advisory message is displayed on the EICAS page.
What MFSs are avilable during landing in each flght control direct mode?
MFSs will not automatically retract in any direct mode.
1) PFCC direct mode
- the ground lift dumping function deploys the MFSs to 5 degrees to prevent excessive nose pitch up after landing.
- the SPOILER lever must be manually moved to the FULL or MAX position for additional MFS deployment
2) In REU and AFCU direct mode
- there is no automatic ground lift dumping function.
- The flight SPOILER lever must be manually moved to the FULL or MAX position for MFS deployment.
Are Slats/Flaps part of the FBW system?
No, but they send inputs to it.
Which hydraulic system controls Flaps and which Slats?
Flaps 1 and 3
Slats 2 and 3
What are synoptic page indication when Flaps or Slats fail?
The slat position indicator displays the slat positions with the words IN, OUT, MID and FULL. If the slats are failed or malfunctioning, the word is displayed in amber and corresponds to the last achieved position.
The flap position indicator displays the flap position with a number from 0 to 5. If the flaps are failed or malfunctioning, the number is displayed in amber and corresponds to the last achieved position.
Which two of the following are part of the high-lift system?
Flaps and Slats
Which flight controls are commanded by the fly-by-wire (FBW) system? (Select two responses.)
Secondary flight controls: horizontal stabilizer, multifunction spoilers, ground spoilers, EXCEPT flaps and slats
Primary flight controls: ailerons, elevators, and rudder
In AFCU direct mode the command signals from the flight deck controls are routed by the alternate flight control unit (AFCU) directly to: (Select two responses.)
a single channel of the horizontal stabilizer motor control electronics (MCE) unit.
one power control unit (PCU) of a control surface with failed remote electronic units.
Which of the following statements are true of the horizontal stabilizer (HSTAB)? (Select two responses.)
Trimmed conventionally in fly-by-wire direct mode
Electrically controlled and electrically actuated
Sidestick position: within the soft stop limits following a high angle-of-attack
AOA remains within operational envelope
Sidestick position: at the hard stop
Max AOA is not exceeded
Sidestick position: at the soft stop
Operational AOA is not exceeded
Sidestick position: at neutral following a high angle of attack
High AOA protection returns AC to trim speed
The remote electronic units (REUs) transmit commands received from the primary flight control computers (PFCCs) to which components?
The hydraulic power control units (PCUs) and the HSTAB motor control electronics (MCE) unit
On landing, multifunction spoilers, ground spoilers, and ailerons deploy to assist in deceleration. In which fly-by-wire modes are ground spoilers not available automatically? (Select two responses.)
AFCU direct mode
REU direct mode
Which two indications occur when simultaneous operation of both sidesticks is detected? (select two responses)
Red DUAL message displays on both PFDs
“DUAL INPUT” aural message is activated
What is the purpose of slat/flap brakes? (Select two responses.)
They lock the surfaces in their commanded positions
They apply during slat/flap asymmetry, or uncommanded runaway extension
In the event of a failure of all three primary flight control computers (PFCCs), the remote electronic units (REUs) receive flight control positioning commands from the
Flight deck controls
When spoilers have been manually deployed, and a bank requiring roll assist is initiated, the fly-by-wire system:
partially retracts the high-wing multifunction spoilers
In the fly-by-wire (FBW) system, which component positions the control surfaces through hydraulic actuators?
Motor control electronics unit
