FLIGHT CONTROL Flashcards
HOW THE ALTN PITCH WORKS?
In the normal mode, alternate pitch trim operates differently on the ground than it does in flight. On the ground, the stabilizer is directly positioned when the pilot uses the alternate pitch trim switches. In flight, the alternate pitch trim switches make changes to the trim reference speed
WHICH ARE THE PITCH ENVELOPE PROTECTION?
OVERSPEED
STALL PROTECTIONS
HOW MANY MODES THERE ARE FOR THE FLIGHT CONTROLS?
3
NORMAL
SECONDARY
DIRECT
HOW IS WORKING THE NORMAL MODE?
In the normal mode during manual flight (autopilot disengaged), four ACEs receive pilot control inputs and send these signals to three PFCs. The PFCs verify these signals and information from other airplane systems to compute enhanced control surface commands. These commands are sent back to the ACEs, then to the flight control surface actuators
When the autopilot is engaged, the autopilot system sends control surface commands to the PFCs. The PFCs generate control surface commands which are sent to the ACEs and then to the control surface actuators.
WHICH ARE THE FLIGHT ENVELOPE PROTECTIONS?
BANK ANGLE, OVERSPEED, BANK ANGLE PROTECTION
HOW IS OPERATING THE SECONDARY MODE?
The PFCs automatically revert to secondary mode when inertial or air data is insufficient to support normal mode or when all slat and flap position data is unavailable. The ACEs continue to receive and process pilot control inputs, and send these signals to the three PFCs. The PFCs use simplified computations to generate flight control surface commands. These simplified commands are sent back to the ACEs, where they are sent to the control surface actuators
WHICH FUNCTIONS ARE NOT AVAILABLE IN SECONDARY MODE?
AUTOPILOT
AUTO SPDBRAKE
ENVELOPE PROTECTION
GUST SUPPRESSION
PITCH COMPENSATION
ROLL/YAW ASYMMETRY COMPENSATION
TAIL STRIKE PROTECTION
WHEN AND HOW DOES THE DCT MODE WORK?
The ACEs automatically transition to the direct mode when they detect the failure of all three PFCs or lose communication with the PFCs.
Pilot inputs received by the ACEs are sent directly to the control surface actuators.
WHICH COMPENSATION IS PROVIDING THE PITCH CONTROL IN NORMAL MODE?
The PFCs provide pitch compensation by utilizing control surface commands to minimize airplane pitch responses to thrust changes, configuration changes (gear, flap, speedbrake), turbulence, and turns up to 30° of bank
PITCH TRIM HOW IS WORKING?
On the ground, the stabilizer is directly positioned when the pilot uses the pitch trim switches. In flight, the pitch trim switches do not position the stabilizer directly, but make inputs to the PFCs to change the trim reference speed. The trim reference speed is the speed at which the airplane would eventually stabilize if there were no control column inputs. Once the control column forces are trimmed to zero, the airplane maintains a constant speed with no column inputs. Thrust changes result in a relatively constant indicated airspeed climb or descent, with no trim inputs needed unless airspeed changes.
In the secondary or direct modes, primary pitch trim operates the same on the ground and in flight
HOW IT WORKS THE ELEVATOR VARIABLE FEEL ?
The PFCs calculate feel commands based on airspeed
TAIL STRIKE PROTECTION HOW IT WORKS?
During takeoff or landing, the PFCs calculate if a tail strike is imminent and decrease elevator deflection, if required, to reduce the potential for tail contact with the ground.
HOW MANY CHANNELS HAS THE STABILIZER?
Stabilizer position commands are processed through two independent channels within the flight control system
COLUMN CUTOUT FUNCTION
The column cutout function is designed to stop the effects of uncommanded pitch trim input from jammed or failed pitch trim switches.
2 SECONDS / 20 SECONDS
WHAT IS AN ( HLFC ) HYBRID LAMINAR FLOW CONTROL
The vertical stabilizer has a Hybrid Laminar Flow Control (HLFC) system installed to reduce aerodynamic drag
