9 - Flight Controls Flashcards
What are the three Primary Flight Control operating modes?
-Normal
-Secondary (can not be manually
selected)
-Direct (handling qualities approx
same as Secondary mode)
Control inputs are sent to ____ , those signals are sent to ____ which send the signals ____ which send enhanced signals to the flight controls.
4 ACEs (Actuator Control Electronics)
3 PFCs (Primary Flight Computers)
back to the 4 ACEs
Which pilot controls have jam override
mechanisms and which are rigidly connected?
Columns and wheels - override
Rudder pedals - rigidly connected
PFCs use information from other airplane systems such as: (5) to compute enhanced signals
Air data
Inertial data
Flap and slat position
Engine thrust
Radio altitude
Roll control provided by?
2 - Ailerons (move down for flaps
5, 15, and 20 to improve TO
performance)
2 - Flaperons (with flap retracted or
extended)
14 - Spoilers
Yaw control provided by?
- Single rudder (almost same height as tail)
- Partial span tab (lower portion that deflects twice as far as the rudder)
In normal mode what locks out during high-speed flight?
Ailerons
Spoilers 5 and 10
What flight control system mode(s) provides envelop protection and what are they? (3)
Normal Mode only
Stall protection
Overspeed protection
Bank angle protection
What is the difference between
Normal and Secondary mode and how is the pilot notified he is in Secondary mode?
PFCs use simplified computations to generate flight control commands
FLIGHT CONTROL MODE
What is not available in Secondary mode? (6)
Autopilot
Auto speedbrakes
Envelope protection
Gust suppression
TAC (Thrust Asymmety Compensation)
Yaw damping (degraded or inop)
What causes the Flight Control System to switch to Direct mode and what is the indication?
Auto - failure of all three PFCs, or ACEs
lose communication with PFCs
Manual - PFC switch to DISC
PRI FLIGHT COMPUTERS
What functions are not available in the Direct mode? (7)
Autopilot
Auto speedbrakes
Envelope protection
Gust protection
TAC (Thrust Asymmetry
Compensation)
Yaw damping
Rudder trim cancel switch
Is there a mechanical backup system in the event of a complete electrical failure for the flight controls? How does it work?
Yes
Cables from the flight deck to the stabilizer and spoilers 4/11 permit straight and level until the electrical system can be restarted
How do PFCs control pitch?
During landing?
PFCs automatically position elevator and stabilizer to generate the commanded maneuver
Command a slight nose down pitch so pilot has to flare
How does pitch trim differ between in the ground and in flight?
On the ground - stab moves
In flight - inputs to PFCs change the trim reference speed. PFCs move the elevator, then move the stab to streamline (stab auto streamlines for thrust and configuration changes )
How does ALT Pitch Trim work?
ALT trim levers linked to the STCMs (Stabilizer Trim Control Modules) by cables and then mechanically to stab. ALT pitch trim commands have priority over wheel switches in all flight control modes and does not disconnect the autopilot.
How does Stall Protection/Overspeed Protection work?
Limits the speed to which the airplane can be trimmed (minimum maneuvering speed (top of the amber band) - VMO/MMO
Describe Tail Strike Protection
PFCs calculate if a tail strike is imminent and decreased elevator deflection (no control feedback)
How does pitch control differ in Secondary or Direct mode from Normal mode?
Moves elevator, there is no trim reference speed. Pitch trim switches move stab. Spoilers 5/10 locked out.