Flight Controls Flashcards
Describe the roles of the Elevator Aileron Computers (ELAC 1 and ELAC 2).
Provide controls for elevator, ailerons and Trimmable Horizontal Stabilizer (THS)
Determines requirements for spoiler and rudder inputs during turns
Both ELACs active, other ELAC will takeover if 1 fails
Describe the roles of the Flight Augmentation Computers (FAC 1 and FAC 2).
▪ Provides control of the Rudder to include:
• Turn coordination
• Yaw damping
• High/Low speed rudder limiting
• Rudder trim
• Only one FAC is active at a time with the other serving as a backup.
Describe the roles of the Spoiler Elevator Computers (SEC 1, SEC 2 and SEC 3).
▪ All SECs are active during operations with each responsible for a specific pair, or pairs, of spoiler panels.
▪ SEC 1 and SEC 2 can provide backup control of the Elevators and THS in the event of a dual ELAC failure.
Describe Normal Law
All protections available
Describe Alternate Law
reverts with multiple failures involving Flight control computer, hydraulic or nav systems
some flight envelope protections lost
Describe Direct Law
when landing gear is lowered during alternate law
flight controls are direct, all protections lost
Mechanical Backup
Flight control computers have failed or all electrical power lost
sidesticks inop, aircraft can be controlled by manual pitch trim, rudder pedals and engine thrust
Abnormal Law
provides sufficient control to recover from unusual attitude
Describe Load factor demand
available in normal and alternate law
stick aft signals positive g-load change
stick forward signals negative g-load change
stick neutral signals zero g-load change
Auto pitch trim
provided by ELACs in normal and alternate law
auto pitch trim for bank angles up to 33 degrees
Describe Maneuver Protection
- Available in Normal AND Alternate law
- Restricts flight control surface movement that would cause the aircraft to exceed its designed structural G-load limits:
Clean or slats extended and flaps retracted: -1 G to +2.5 G
Flaps extended: 0 G to +2.0 G
Describe Pitch protection
only available in normal law
ELACs allow no greater than 30 degrees nose up or 15 degrees nose down
Describe High speed protection
only available in normal law
prevents aircraft from exceeding vmo/mmo
autopilot automatically disconnects
ELACs automatically pitch aircraft up
Describe Alpha Protection (Alpha Prot)
Available only in Normal Law.
Flight control computers prevent the aircraft’s angle of attack (AOA) from exceeding a predetermined threshold at low airspeeds.
The autopilot automatically disengages and speed brakes, if deployed, automatically retract.
Flight control computers logic changes from Load Factor Demand to direct sidestick pitch control.
Pilot sidestick input can override the Flight Control computers and further degrade the AOA.
Describe the indication of Alpha Prot on the airspeed indicator.
amber and black band
Describe Alpha Max and how it is indicated on the airspeed indicator.
Red band
highest AOA that computer will allow
cannot be overridden
available only in normal law
Describe roll rate in Normal Law.
15 degrees per second
half sidestick deflection yields half roll rate
neutral sidestick yield zero change in roll rate
Describe Bank Angle Hold and Positive Spiral Static Stability.
available only in normal law
bank angle hold: auto pitch trim provided for up to 33 degrees of bank
pos spiral stability: beyond 33 degrees, if the sidestick is let go, aircraft will return to 33 degrees of bank
Describe the role of Automatic Pitch Trim during turns.
available in normal and alternate law
ELACs provide back pressure through auto pitch trim with 33 degrees of bank or less
Above 33 degrees, sidestick back pressure must be introduced
Describe bank angle protection
normal law, bank limited to 67 degrees
Recall the indications of Normal Law on the PFD.
▪ Green equal signs displayed at:
• 67º bank angle limit.
• +30º and -15º pitch attitude limits.
• High speed protection limit.
Describe the Ground, Flight, and Landing modes of Normal Law.
Ground
Flight
Landing
Ground: control inputs direct to allow flight control checks
Flight: active after takeoff, all protections active
Landing: at 50 ft RA, ELACs memorize aircraft pitch attitude
at 30 ft RA, ELACs add nose down command
after landing, aircraft returns to ground mode and THS resets to zero
Explain how roll control is maintained while in Alternate Law.
Direct relationship exists between sidestick deflection and elevator/aileron deflection.
All roll control flight characteristics and protections are lost.
High and Low Speed stabilities in Alternate Law.
o High Speed Stability:
▪ Becomes active slightly below VMO/MMO
▪ ELACS command the elevators to increase the aircraft’s pitch, attempting to prevent an increase inspeed.
can be overridden by sidestick input.
o Low Speed Stability:
▪ Becomes active at airspeed slightly higher than stall speed.
▪ Flight control computers command the elevators to decease aircraft’s pitch, attempting to increase
airspeed.
can be overridden by sidestick input.
