FLIGHT CONTROL MODES Flashcards
What are the different flight control modes?
Normal, Secondary, and Direct.
What protections do you have in Normal flight control mode?
S Stall Protection
O Overspeed Protection
B Bank angle protect
T TAC (Thrust Asymmetry Compensation) Computer A Auto pilot G Gust supression R Rudder cancel A autospeed brakes T tailstrike protect Y Yaw Dampering W wheel x-tie
What causes Flight Control to switch to Secondary Mode?
Loss of inertial or speed reference
What do you lose in Secondary Mode?
Stall Protection Overspeed protection Bank Angle protection TAC computer autopilot Gus supression Autospeed brakes tailstrike protection wheel x-tie Yaw Dampering with loss of inertial data
What do you keep in Secondary mode?
Rudder cancel
Degraded w/ inertial data
What causes Flight Control to switch to Direct mode?
Loss of other references or by switching PFC switch to disconnect
What do you lose in Direct Mode
Everything:
stall protect overspeed protect bank angle protect tac computer autopilot gust supression rudder cancel autospeed brakes tailstrike protect yaw dampering wheel x-tie
What is Stall protection?
Reduces possibility of stick shaker
No trim below VMC speed
Autothrottles engage automatically
Stick Shaker activates at the min speed displayed on the PFD/no aural warning
What is Overspeed Protection?
Limits the speed to which the airplane can be trimmed.
Requires constant forward force above VMO/MMO
Limits speed the aircraft can be trimmed to VMO/MMO
Gives EICAS warning “OVERSPEED” and aural tone alerts the crew
Releasing the forward force allows the 777 to return to a speed below VMO/MMO
What is Band Angle Protection?
For banks 30 degrees or less, back pressure is not required
Partial compensation needed for banks 30-60
When exceeding 35 degrees bank, PFD pointers changes to amber and more force is required to maintain bank.
Wheel forces cease when roll returns to 30 degrees or less
What is TAC?
Thrust Asymmetry Compensation.
Assists in maintaining directional control after engine failure.
Immediately counters assymmetry with a high rate of rudder command.
Assists also when thrust levers are split
Armed above 70kts but NOT available in reverse thrust
When is TAC unavailable
Thrust Asymmetry Compensation is unavailable:
Below 70 kts
In Reverse Thrust
In Secondary and Direct Mode
What is Wheel X-tie
Wheel to Rudder Crosstie:
Controls the initial effect of engine failure in control wheel only. No rudder needed.
When is Wheel X-tie unavailable?
At speeds of 210 kts or greater
In Secondary and Direct modes
What do the slats do in the secondary mode?
If they are up when the system goes to secondary, they go to full extend as soon as flaps are selected. If they are at mid when the system goes to secondary, they remain at the mid-position.
