Flight Controls Flashcards
What is the meaning of a flag on the Stab Trim Indicator?
If in view trim indicator is INOP
When are spoiler panels automatically commanded UP (extended)?
Speed Brake Lever DN (not armed)
- main landing gear on the ground
- Eng 1 AND 3 thrust levers idle and Eng 2 OR 4 thrust reverser lever raised
- spoilers will retract if Eng 1 OR 3 thrust lever moved above idle (go around protection)
Speed Brake Lever ARMED:
- main landing gear on the ground
- Eng 1 AND 3 thrust levers idle
- spoilers will retract if Eng 1 OR 3 thrust lever moved above idle (go around protection)
Flap Lever Positions and Normal TO/LNDG ranges
UP 1 - stop gate - Inboard and Midspan Leading Edge Flaps extend 5 - all leading edge flaps extend 10 - normal TO range 20 - stop gate - normal TO range 25 - normal LNDG range 30 - normal LNDG range
In transit what does the white flap position indicator translate?
The actual position fo the slowest trailing edge flap group
What EICAS messages indicate Flaps are not operating normally?
- FLAPS CONTROL
- FLAPS DRIVE
- FLAPS PRIMARY
Flight Control Surfaces
Pitch:
- 4 elevator surfaces
- movable horizontal stabilizer
Roll:
- 4 ailerons
- 10 (of 12 panels) spoilers
Yaw:
- upper and lower rudder
Elevator Control
- hydraulically actuated, mechanically commanded through control wheel
- inputs hydraulically actuated inboard elevators
- Left Inboard: HYD 1 and 2
- Right Inboard: HYD 3 and 4
- inboard elevator panel position controls related outboard elevator actuator
- Left Outboard: HYD 1
- Right Outboard: HYD 4
- Artificial feel provided thought Elevator Feel Unit (HYD 2 and 3)
- elevator feel a function of airspeed
Stabilizer Trim
2 Channels:
- Normal (control wheel trim switches)
- Alternate (alternate trim switches
2 Stabilizer Trim Control Modules each command an actuator
- HYD 2 ——> Stab Trim Control Module
- HYD 3 ——> Stab Trim Control Module
- with only one STCM trim is at 1/2 rate
*Alternate Trim overrides autopilot and does not disengage AP
How is takeoff trim calculated?
- FMS gross weight
- center of gravity
- takeoff thrust selection
- takeoff flap setting entry
- green band is cross checked with position of nose hear pressure switch
Speed outboard ailerons are locked at neutral
238 knts
Which control surfaces are available for roll control with a control wheel jammed?
- ailerons corresponding to free control wheel
- half the flight spoilers
Which spoiler surfaces are used for roll control in flight?
All surfaces except inboard spoiler
Aileron Control
Inboard and Outboard Ailerons are hydraulically controlled
Left Outboard - HYD 1 and 2
Right Outboard - HYD 3 and 4
Left Inboard - HYD 1 and 3
Right Inboard - HYD 2 and 4
What’s installed to overcome a flight control surface jam?
Elevator - shearouts between inboard and outboard surfaces
Aileron - shearouts between control wheels
Rudder - shearouts in rudder system
*significant force must be applied to control wheel or rudder pedals
Purpose of Rudder Ratio Changer
- two rudder ratio changer systems (Upper and Lower)
- reduces rudder surface response as airspeed increases
- protects vertical tail from stress from large rudder inputs at high airspeed
Purpose of Yaw Dampers
- two yaw dampers (upper and lower)
- upper powered by HYD 3
- lower powered by HYD 2
- improve lateral and directional stability
- provides turn coordination
- counters yaw with control inputs to prevent Dutch roll tendency
Rudder Control
Mechanically controlled via rudder pedals, hydraulically actuated
- upper surface has 3 actuators (HYD 1 - top; HYD 3 - middle and bottom)
- lower surface has 2 actuators (HYD 4 - top; HYD 2 - bottom)
Rudder trim is available through rudder trim selector
-rudder feel and trim mechanism reposition neutral point
How many spoiler surfaces?
12 spoilers (6 per wing)
- all 6 panels on each wing for ground spoilers
- 4 inboard on each wing used for speed breaks
- 5 outboard used for roll
- left wing 4th spoiler in from wingtip used for EICAS position
- right wing outboard-most spoiler used for EICAS position (will not show Speedbrake indication)
Which Hydraulic Systems control spoilers?
HYD 2, 3, and 4
3,2,2,3 4,4 4,4 3,2,2,3
Flap Groups
Leading Edge (pneumatically powered from bleed air)
- outboard group
- midspan group
- inboard group
Training Edge
- inboard group (powered by HYD 1)
- outboard group (powered by HYD 4)
How many leading edge flaps?
Inboard - 3
Midspan - 5
Outboard - 6
How are the flaps controlled?
Flap lever transmits desired position to Flap Control Units
- 3 identical FCUs
FCUs:
- control flaps in primary or secondary mode
- control flap sequencing
- control asymmetry, disagreements, and uncommanded motion
- control flap and load relief in primary mode only
- send flap position information to EICAS and other systems
Drive Units
- each LE Flap group has its own unit
- pneumatic power in Primary Mode
- electric motor secondary/alternate mode
- each TE Flap group has its own unit
- hydraulic power in Primary Mode
- electric motor secondary/alternate mode
Flap control modes
Primary:
- leading edge pneumatically from bleed air
- trailing edge hydraulically (HYD 1 and 4)
Secondary
- leading and trailing edge flaps driven through electric motors
- flaps move much slower than in Primary mode
Alternate
- FCUs are bypassed
- all flaps are extended or retracted by electric motor
- flap lever inoperative
Flaps Sequencing
Primary and Secondary Modes:
Up to 1: leading edge inboard and midspan groups extend
1 to 5: leading edge outboard group extend and all trailing edge groups move to 5
10, 20, 25, 30: trailing edge groups move to selected position
Alternate mode:
Extension: leading and trailing edge flaps extend immediately
*maximum extension for trailing edge flaps is 25
Retraction: all leading edge flaps retract after all trailing edge flaps have been retracted
Flap Load Relief
- only available in Primary Mode
- if airspeed limit is exceed in flaps 25 or 30 flaps will retract to 20 or 25 as needed
What happens to Elevator Feel if HYD SYS #2 and #3 fail?
- The Elevator Feel Sys is unavailable
- feel forces are provided by mechanical springs
- elevator feel is not a function of airspeed
Purpose of STAB TRIM CUT OUT switches
- control hydraulic pressure to STCMS
- In AUTO: HYD pressure is automatically cutout for uncommanded trim
- CUTOUT: manually disables the affected trim system
- ON: overrides automatic cutout
Which spoiler panels are referenced on the STAT synoptic page?
- Panel #4 (Roll spoiler, ground spoiler, speedbrake)
- Panel #12 (roll spoiler, ground spoiler)
Position for flight spoilers with lever in FLIGHT DETENT
- two inboard spoilers move to mid-travel position
- two middle spoilers move to full-travel position
> SPEEDBRAKES EXT
Lever aft of ARM:
- between 15’ RA and 800’ RA; or
- flaps set for landing; or
- two more more thrust levers forward of idle
How is rudder trim applied?
- Manual rotation of rudder control knob
- activates a motor which gives input to feel and trim unit
- feel and trim unit repositions the neutral point
What happens if a rudder ratio changer fails?
- the response of the associate rudder panel or the rudder pedal inputs remain the same as when the failure occurred
Does the Stab Trim switch on the control wheel cause autopilot disconnection?
- With single AP engaged: YES
- With multiple APs engaged: control wheel switches inhibited
What does the Alternate Flap Arm switch do?
- turns off primary and secondary mode
- arms alternate control mode
If one flap group fails to secondary mode what happens to the remaining flap groups?
- The symmetrical flap group on the other wing will switch to secondary
- LE Midspan and Inboard switch to secondary together
*
FLAP DRIVE EICAS message
- One or more flap groups fail to drive in secondary mode, or
- asymmetry condition detected
Purpose of Spoiler Mixers
Combine Speedbrake Lever and Control Wheel inputs allowing roll inputs to deflect spoiler panels up and down when Speedbrakes and ground spoilers are in use
> STAB GREENBAND
Nose gear pressure switch disagrees with the calculated stabilizer green band
Amber X on Flap Indication
- position sensor for flap has failed
- when STBY Bus is the only AC source, left wing trailing edge flaps sensors are not powered (left outboard & left inboard) - amber X’s will be displayed
Amber Solid Box/Crosshatch/Open Box on expanded flap indication
Amber Solid Box - drive unit inop with flap group retracted
Amber Crosshatch - drive unit inop with flap group in transit
Amber Open Box - drive unit inop with flap group extended
