787 SYS 3 Flt Cntrls Flashcards
In NORMAL flt cntrl mode, yaw controls attempts to maintain zero yaw rate due to engine failure when above what
60 knots ground speed on the ground
What are the 3 primary flt cntrl system modes and how are they selected
1) NORMAL
2) SECONDARY
auto with IRU or AHRU fault or all slat/flap position data loss
3) DIRECT
Auto or Manually (Loss of all 3 PFC or turning them off)
What Spd does rudder become aerodynamically effective
~60 knots
How does pitch trim differ between the NORMAL, Secondary, DIRECT MODES
-Secondary, Direct and Normal on ground..pitch trim moves Stabilizer
-Normal, in air..trim input sent to PFC that moves elevator and trims for predicated Spd then moves Stabilizer to streamline
Slat AUTOGAP helps at slow speed by extending Slats from middle to full at high AOA. What mode is it available and what speed does this occur for -8 and -9/10
-NORMAL
-8..225kts
-9/10…240kts
What Flt Cntrl mode is is SLAT PREGAP used, why isn’t it AUTOGAP, and what speeds does it enable for -8 and -9/10
-Secondary
-in secondary the system is to slow to respond to AUTOGAP
—8..225 knots; -9/10…240 kts
What does the Wheel to Rudder Cross-Tie do, and what Flt Cntrl modes is it available
-Reduces maximum sideslip and vertical fin loads
-Secondary and Direct
FLAP/SLAT LOAD RELIEF is the same for all variants. What Flap setting is it active
15 to 30
In the secondary flight control mode what functions are not available
-2 Autos (pilot/Spd Brakes)
-2Compensations (pitch and roll/yae assymetry)
-2Protections (envelope/tail strike)
-1Suppression (gust)
Which flt cntrl mode is this
Normal
Inputs from controls are translated into Analog and sent to ACEs. ACEs Send to PFCs which calculate the control position command and send it back to ACEs. ACEs convert the data back to analog and then send to PCUs
CONTROL SUFACE HYD PWR
-Ailerons
-Elevator
-Rudder
-Flaperon
-Stab
-Rudder
-A: side and center
-E: side and center
-R:
-F: Left=L&R; Right=L&C
-S:
-R: All 3
This is the secondary mode. What is the difference in the PFC info sent back to the ACEs and what is the control degradation
-PFCs send simplified commands
-Elevator and Rudder are more sensitive at some speeds and yaw damping is degraded
This is the Direct mode. How is Direct Auto and Manually entered
-Auto: ACEs detect failure or lost comm with all 3 PFCs
-Man: select disconnect on Primary Flight Computers switch (panel 1 middle)
How does degrading to Direct differ from Secondary
-Same
Your in the green, do why do you have this EICAS
-disagreement btwn computed green band and OLEO transducers data
-OLEO transducers out of tolerance
-either OLEO transducer has failed
Alternate vs primary pitch trim commands…which wins in all flight control modes
Alternate
How does Alternate Pitch Trim switches operate on the ground and in flight for all three modes
-Normal Air -sets new trim ref speed
-Normal ground and ground/air for Secondary and Direct it directly moves the stab
What is this speed and what happens when you reach it re: stall protection
-Vmm - min maneuver
-nose-up trim inhibited below this spd
What speed is this and what happens at this speed
-Vmin
-Stick shaker
What are the 3 Pitch Envelope protections
-over speed
-stall
-tail strike
What speed is overspeed protection provided and what are the indications
-Vmo/Mmo
-EICAS WARN OVERSPEED
-Aural Warning Siren
-Trim Ref change inhibited nose down
What happens to thrust as speed decreases to near stick shaker
-If Autothrottle is armed but not engaged it will AUTO activate is SPD mode with thrust set for Vmm (top of Amber band) or the Spd set in MCP
-EICAS CAUTION AIRSPEED LOW
What are the exceptions to Autothrottle Auto activation for Low Spd
-Won’t activate if:
–Pitch mode FLCH or TO/Ga
–<400’ takeoff; <100’ approach
—Descent in VNAV SPD w/ Autothrottles in HOLD
What system monitors for Tailstrike protection, what do they do, does it keep pilot from striking
1) PFCs
2) decrease Elevator deflection
3) No…pilot can override
What does the LAM (Land Attitude Modifier) do, when does it apply, and how does it do it
-increases pitch attitude and nose gear height
-higher speed landings with flaps at Landing (20, 25, 30)
-undroops flaperons and raises inboard spoilers
How is the Stabilizer moved
-Pitch commands from PRI/ALT pitch trim switches sent to Stab
-STAB is moved by ECU (elec cntrl unit) powered by L2 & R2 AC buses
Bank angle protection:
-What mode is it available
-When does it kick in
-What does it do
-Normal only
-Bank >35deg
-control wheel force back to within 30deg
What does pulling down your n A/P disengage bar do to bank angle protection
Disables
What does this indicate
Bank angle >35
If you lose all HYDs, what controls are available and how are pitch and roll maintained
-Electrically actuated Stab/two spoiler pairs
PITCH: primary and alternate pitch switches and control wheel
If you have complete loss of flight control signaling, how is the aircraft flown, and which control surfaces are direct wired for this
-Pitch: ALTN PITCH TRIM
-Roll: control wheel
-Stab and spoiler pair
When is the Flap and Slat airspeed and altitude extension inhibited and what modes offer this protection
1: 260 kts / 20,000’
2: Primary and Secondary
