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
WHAT IS THE BANK ANGLE PROTECTION?
PROVIDES A ROLL INPUTS BACK TO 30 DEGREES IF THE BANK EXCEEDED 35 DEGREES.
ONLY ON PRIMARY MODE
HOW IT WORKS THE ROLL IN NORMAL MODE?
DOES NOT POSITION DIRECTLY THE SURFACES IN FLIGHT, INSTEAD COMMAND A ROLL MANEUVER AND THE FLIGHT CONTROL SYS WILL TRANSLATE IT IN SURFACE MOVEMENTS
HOW IS WORKING THE ROLL SECONDARY MODE ?
USING A SIMPLIFIED COMPUTATION
HOW IS WORKING THE YAW DAMPER CONTROL IN NORMAL MODE?
INSTEAD OF MOVING THE RUDDER IT WILL COMMAND A SIDESLIP
ASYMMETRY COMPENSATION
THE FLIGHT CONTROL ATTEMPTS TO MAINTAIN ZERO YAW RATE BY APPLYING AUTOMATICALLY RUDDER CORRECTIONS.
DURING REVERSE OPERATIONS OR TAKE OFF IN CROSSWIND.
IN FLIGHT IF ANY ASYM OCCURS THE SYSTEM TRY TO MAINTAIN A ZERO YAW AND SIDESLIP, AFTER THE FIRST ACTION WILL OFFLOAD EVERYTHING ON THE RUDDER.
WHAT IT FOR THE YAW DAMPING?
CONTROL DUTCH ROLL AND HELPING IN TURN COORDINATION
GUST SUPPRESSION
THIS FUNCTION ENHANCE THE RIDE QUALITY IN PRESENCE OF VERTICAL GUSTS AND TURBULENCE. WORKS IN VNAV OR ALT HOLD MODE ONLY.
ONLY IN NORMAL MODE
RUDDER TRIM
CONTROLLED WITH A SWITCH IN THE AFT AISLE STAND, HAS TWO RATES FAST AND SLOW,
ALL MANUAL TRIM INPUT ARE ZEROED ON TAKE OFF AND WHEN IN AUTOLAND IN LAND3 APPROACH
YAW CONTROL IN SECONDARY AND DIRECT MODE
DIFFERS FROM NORMAL MODE, USING SIMPLIFIED COMPUTATIONS, COMMANDING PROPORTIONAL RUDDER DEFLECTIONS
HOW MANY SPOILERS THERE ARE? AND HOW THEY ARE POWERED?
TOTAL OF 7 SPOILERS PER WING, 5 OF THEM POWERED BY HYDRAULICS, THE REMAINING TWO ELECTRICALLY
IN THE ARMED POSITION THE SPEEDBRAKE LEVER WHEN WILL MOVE TO UP?
WHEN THE MAIN GEAR WILL TRUCKS UNTILT AND BOTH THRUST LEVERS ARE NOT IN TAKE OFF RANGE
IF THE SPEEDBRAKE LEVER IS NOT IN ARMED POSITION WHEN THE SPOILERS WILL AUTOMATICALLY RAISE UP?
DURING RTO FOR EXAMPLE WITH SPEED ABOVE 85KTS AND BOTH THRUST REVERSED RETARDED TO THE IDLE REVERSE POSITION
SPEEDBRAKE EXTENDED AUTOMATICALLY RETRACT IF?
AFTER TOUCH DOWN THRUST LEVERS ARE ADVANCED,
TRANSITION BACK TO THE AIR
IN THE AIR WHEN TRUST LEVERS ARE 90% FWD
AUTODRAG
WORKS ONLY WITH FLAP 25 ORE GRATER TO INCTP THE GS FROM ABOVE, DEPLOYING THE SPDBRAKE PARTIALLY TILL 500 FT then stow them
When flaps are inhibited to avoid unwanted selection?
Above 20000 ft and above 260 kts
Flap slat modes?
Primary
Secondary
Alternate
How flap and slat are controlled in primary mode?
Flap and slat are controlled together, and autogap function is available
What trigger the secondary mode in the control of flap or slat?
In secondary mode the flap or slat are controlled separately, either hydraulically or backup electrical flap limited to FLAP20
Center hyd failed
Surfaces moves 50% lower rate then normal
Disagree detected
Primary slat and flap mode fail
Uncommanded motion detected
WHEN LOAD RELIEF WORKS?
ONLY IN PRIMARY MODE AND FROM FLAP 15 TO FLAP 30 AUP TO F5 RETRACTION NOT MORE
AUTOGAP PREGAP?
AUTOGAP CONNECTED WITH AOA
PREGAP WITH SPEED
BELOW 240 KTS HIGH AOA THE AUTOGAP MOVES THE SLAT FULL EXTENDED
IN PREGAP SECONDARY MODE THE SYS IS TO SLOW TO ACT LIKE AUTOGAP SO WHEN SPD IS BELOW 240 SLAT ARE FULLY EXTENDED
CRUISE FLAP
INCREASE WING CAMBER AND WORKS ABOVE 25000 FT and MACH 0.54 / .87
