Flight Controls Flashcards
What drives the primary flight control surfaces?
Power control units (PCUs) drive the primary flight control surfaces.
How many spoilers are there?
14 spoilers, 7 on each wing
Roll control is provided by?
2 ailerons, 2 flaperons
High lift control system contains?
- 7 slats (on the leading edge of each wing)
- 2 Krueger flaps
- 2 outboard trailing edge flaps
- 2 inboard trailing edge flaps
What are the 3 primary flight control system modes of operation?
- Normal
- Secondary
- Direct
How are control inputs made in the 777 fly-by-wire system?
- Inputs through the control column, wheel, rudder pedals and speedbrake lever are converted to analog electrical signals.
- These analog signals go to 4 Actuator Control Electronics (ACEs), convert analog signals to digital signals.
- Digital signals from the ACEs are sent to 3 Primary Flight Computers (PFCs).
- From various airplane systems, the PFCs receive Airspeed data, Inertial data, Angle of attack data, Flap position data.
- PFCs calculate the flight control position commands requested by the pilot and sends them back to the ACEs.
- ACEs convert the digital signals back to analog form and sends them to the flight control surface actuators.
- The actuators provide the muscle to operate the flight controls.
When does the primary flight control system automatically switch to the Secondary Mode?
- Internal failure
- Lack of information detected from other systems
What is not available in the Secondary Mode?
- Autopilot
- Auto speed brakes
- Envelope protection
- Tail strike protection
- Thrust Asymmetry Compensation
- Yaw Damping
- Other protection features
What are the 2 ways the primary flight control system can be switched to the Direct Mode?
- Automatically if all 3 PFCs fail
- Manually, by selecting DISC on the PRIMARY FLIGHT COMPUTERS switch.
What functions are not available in the Direct Mode?
- Autopilot
- Manual rudder trim cancel switch
- Auto speed brakes
- Thrust Asymmetry Compensation (TAC)
- Envelope protection
- Yaw damper
- Gust suppression
- Tail strike protection
What does the green band on the stabilizer position indicator indicate?
The illuminated green band, computed by the FMC, displays the allowable range of the stabilizer for takeoff.
The green band on the stabilizer position indicator is positioned by the FMC and is based on?
- Gross weight
- Takeoff thrust
- CG information
When does the green band on the stabilizer position indicator default to the midrange?
- No information is available
- V1 is not selected or entered
When is the green band and the pointer on the stabilizer position indicator not displayed?
If the stabilizer signal is not present or is invalid.
Flight envelope protection features include?
- Stall protection for pitch
- Overspeed protection for pitch
- Bank angle protection for roll
Yaw control is provided by?
- Rudder pedals
- Rudder trim system
- Rudder ratio system
- Yaw dampers
When does automatically add rudder to minimize yaw during an engine failure?
When engine thrust differs by more than 10%.
When does TAC automatically disengage?
- Engine thrust data is lost
- Engine is damaged
- Engine surges
When is TAC not available?
- Airspeed is below 70 knots on the ground
- Reverse thrust is applied
- Automatically disengaged due to system malfunctions
- Loss of engine thrust data
- Flight controls are in secondary or direct modes
What is the purpose of the control wheel/rudder cross-tie?
Enables the pilot to control initial asymmetry solely through control wheel inputs.
When is the wheel to rudder cross-tie operative?
In the normal mode, wheel to rudder cross-tie is operative in flight below 210 knots.
What are the 3 modes of operation for the flaps and slats?
- Primary
- Secondary
- Alternate
In primary mode, flap load relief operates for flap selections?
15 - 30
When does the secondary mode automatically engage?
- Primary flap or slat mode fails
- The center hydraulic system fails
On the ground, secondary electric mode extension or retraction is inhibited when?
- Groundspeed is less than 40 knots
- Center hydraulic system pressure is low
- And two of the following three conditions are met:
- Left engine N2 is less than 50 percent
- Right engine N2 is less than 50 percent
- Primary external power is available
What happens when the ALTN FLAPS ARM switched to ARM?
- Arms the alternate flap control mode
- Arms the alternate flap selector
- Disables primary and secondary flap/slat operation
- Flap lever is inoperative
What is not available in the alternate mode?
- Asymmetry protection
- Uncommanded motion protection
- Autoslats
- Flap/slat load relief
