Flight Controls Flashcards
The primary flight control system consists of:
- ailerons and multi-function spoilers
- elevators
- rudder
The secondary flight control system consists of:
- horizontal stabilizer
- flaps and slats
- multi-function spoilers used as speed brakes or ground spoilers
- dedicated ground spoilers
The primary flight control electronics are generally comprised of two parts:
- the Primary Actuator Control Electronics (P-ACE)
- the Flight Control Module (FCM)
Flight Control Mode Button PUSH IN/PUSH OUT
IN - direct mode
OUT - normal mode
Name the nine Actuator Control Electronics (ACEs)
- three primary ACEs (P-ACE)
- two slat/flap ACEs (SF-ACE)
- one horizontal stabilizer ACE (HS-ACE)
- three spoiler ACEs (S-ACE)
How many flight control modules (FCM)?
four
How many channels does each ACE have?
two, one active and one standby
Location of P-ACEs
fwd ebay - 2
aft ebay - 1
Location of SF-ACEs
middle ebay
Location of HS-ACE
aft ebay
What do the FCMs do?
provide software based assistance to the P-ACE by providing higher level function augmentation to pilot inputs
FCM location
FCM 1 and 2 - MAU 1
FCM 3 and 4 - MAU 3
Name the higher level functions that the FCM provides in “normal mode”
- elevator control laws w/ airspeed
- auto thrust compensation with elevator
- mach trim and autopilot trim
- AOA limiting with elevator offset
- rudder airspeed gain scheduling and stroke limiting
- yaw damper and turn coordination via AFCS
- rudder flight authority
- roll spoiler scheduling and speed brake deployment
- automatic spoiler deployment at high mach number
- configuration change compensation with horizontal stabilizer
Describe direct mode
FCM is removed from control loop because of loss of data or multiple failures in both ACEs
What is the CAN BUS
Controller Area Network; communication link between the FCMs and the P-ACE units
The following systems provide data to the flight control system:
- smart probes and Air Data Application modules
- IRS
- Proximity Sensor Electronic Modules (weight on wheels)
- Brake Control Modules
- FADEC provides thrust lever angle
Describe the Fly By Wire Backup system
a dedicated backup battery with internal heater keeps elevator and rudder actuators operating for at least 15 minutes, charged by DC ESS 3
Describe the pitch system components
- electro-hydraulic commanded elevators
- electro-mechanical horizontal stabilizer
How many elevator PCUs
four, operate on active/standby mode alternating every time elevator system is powered up
Which hydraulic system power which elevator PCU
1 - left outboard
2 - left and right inboard
3 - right outboard
What happens during an elevator jam
if jam in one elevator actuator, respective elevator surface remains fixed in position, pilot controls remaining elevator
Elevator/Rudder Flight Control Panel Button
cycles between normal or direct mode and cycles active and standby PCUs
Describe the Elevator Thrust Compensation Function
helps reduce pilot workload by applying elevator commands to reduce pitching moment by increasing or decreasing engine thrust
Describe the elevator Artificial Feel Units
provide the feel and centering force for the control columns, consist of pre-loaded springs
Describe the elevator Disconnect Mechanism
allows separation of control columns in the event of a jam, mx must reset on ground
Control of the Horizontal Stabilizer is commanded by:
- wheel main trim switches
- pedestal mounted back up trim switches
- FCM for autopilot trim and speed brake auto trim
What is used to control the horizontal stabilizer
- HS-ACE
- Horizontal Stabilizer Actuator
Describe the Horizontal Stabilizer Actuator
single electrical-mechanical actuator with two DC motors (active/standby)
HS-ACE trim command priority
- back up switches
- captain
- first officer
- FCM auto trim
Manual pilot trim commands are limited to
3 seconds
What causes a low rate condition in the horizontal stabilizer actuator
- electrical emergency
- loss of airspeed data from FCM
Autopilot trim function will be active only if:
- autopilot engaged
- configuration trim is operational
- manual electric trim is not active
- on side autopilot channel is priority
Describe the aileron control system
conventional cable connected to two hydromechanical actuators for each aileron
Which hydraulic system powers which aileron actuators
2 - left and right inboard PCUs
3 - left and right outboard PCUs
How does the aileron system handle jams
divided into left and right systems which can be disconnected, thereby allowing movement in the functional half
Name the 6 multi function spoiler panels
inboard to outboard
L3 L4 L5 (left wing)
R3 R4 R5 (right wing)
Describe the multi function spoiler jam
captain controls outboard spoilers, first officer controls middle spoilers, inboard become disabled
Describe the roll trim system
adjusts neutral position of control wheel
How many rudder PCUs?
two (active/standby)
Who powers which rudder PCU
captain - upper
first officer - lower
Which hydraulic system powers which rudder PCU?
1 - upper
3 - lower
Describe a rudder pedal jam
rudder remains active and will be actuated by high-level functions
Describe a rudder PCU jam
rudder will be hydraulically locked at the current position
How many slat surfaces
eight (four per wing)
How many flap surfaces
four double slotted flap surfaces (two per wing)
Slat and flap motion sequence
slats extend first, flaps retract first
How are the slats and flaps deployed
electrical commanded and operated using Power Driver Units (PDUs), four flaps actuators per side, eight slat actuators per side
If an excessive load is detected on the flaps PDUs:
electrical power is stopped to that PDU, can still be commanded in opposite direction or both directions (for three consecutive attempts)
What happens to flap/slats during RAT deployment
- operate at half speed
- prevents deployment beyond position 3
What happens after a flap/slat failure
affected surface is de-energized, non affected surface still commanded except for:
- flaps beyond 10 degrees with slats below 15 degrees (flaps 2 limits flap deflection to 10 degrees)
How many spoiler panels total
10 (5 per wing)
Multifunction spoilers have three modes of operation:
- roll control
- speed brakes
- ground spoilers
Hyd system 1 powers which multi function spoiler panels?
left and right inboard and middle (L3, R3, L4, R4)
Hyd system 2 powers which multi function spoiler panels?
left and right outboard (L5, R5)
Hyd system 1 powers which dedicated ground spoiler panels?
left and right outboard (R2, L2)
Hyd system 2 powers which dedicated ground spoiler panels?
left and right inboard (R1, L1)
Spoilers deploy on ground during the following condition:
- WOW
- wheel speed above 45 kts or airspeed above 60 KIAS
- TLA below 26 degrees
When do the ground spoilers automatically retract?
- wheel speed below 45 kts for at least 5 seconds
- throttles moved beyond 35 degrees
When are ground spoilers and/or speed brakes not available
direct mode
When will speed brakes automatically retract?
- slat/flap 2 or above
- airspeed below 180 KIAS
- TLA beyond 70 degrees
ELEV (RUDDER) (SPOILER) NML MODE FAIL warning
normal mode no longer operative
GROUND SPOILERS FAIL warning
one of the ground spoiler surfaces has extended inadvertently or has failed to extend when commanded
AOA LIMIT FAIL caution
stall protection function has failed
ELEV THR COMP FAIL caution
one or more sensors required to perform Elevator Thrust Compensation function has failed and the function is no longer available
ELEVATOR FAULT caution
left and right elevator control system has reverted to direct mode
ELEVATOR (LH or RH) FAIL caution
left or right elevator control system has reverted to direct mode
FLAP FAIL caution
both flaps electronic control channels are inoperative and the flap system is no longer available or there is a jam in the mechanical portion that precludes the flaps from moving
FLT CTRL BIT EXPIRED caution
50 hours or more has passed since the last time PBIT was activated
FLT CTRL NO DISPATCH caution
one of the components associated with the flight control system has failed to a no-go position
PITCH TRIM FAIL caution
pitch trim function is no longer available
RUDDER FAIL caution
active and standby rudder channels have failed or rudder has jammed
RUDDER FAULT caution
indicated that the rudder control system has reverted to direct mode
RUDDER LIMITER FAIL caution
indicates that rudder ground authority is retained after takeoff
SLAT FAIL caution
both slats electronic control channels are inoperative and the slats system is no longer available; or there is a jam in the mechanical portion that precludes the slats from moving
SLAT-FLAP LVR DISAG caution
flaps were commanded above VFE
SPOILER FAULT caution
airspeed gain scheduling has failed in one or more pairs of multi function spoilers, and the system has defaulted to a fixed gain
STAB LOCK FAULT caution
the mechanical device that locks the horizontal stabilizer has failed, direct mode is not allowed
AILERON (LH or RH) FAIL advisory
indicates that the left or right aileron is no longer available or there is a mechanical disconnection in the surface
AUTO CONFIG TRIM FAIL advisory
pitch trim auto configuration function is inoperative
FLAP LO RATE advisory
one of the flaps electronic control channels is inoperative and the flap system is still available but running at low speed
FLT CTRL FAULT advisory
one of the components associated with the flight control system has failed
PITCH CONTROL DISC advisory
control columns are disconnected
PITCH TRIM BKUP FL advisory
backup pitch trim switch is inoperative
PITCH TRIM SW 1 FAIL advisory
captains pitch trim switch is inoperative
PITCH TRIM SW 2 FAIL advisory
first officers pitch trim switch is inoperative
ROLL CONTROL DISC advisory
control wheels are disconnected
SLAT LO RATE status
one of the slats electronic control channels is inoperative and the slat system is still available but in low speed
