Flight Controls Flashcards
Describe the roles of the Elevator Aileron Computers (ELAC 1 and ELAC 2).
▪ Provides control of the Elevators, Ailerons, and Trimmable Horizontal Stabilizer (THS).
▪ Determines requirement for and activates spoiler assist during rolls, and rudder input for yaw.
▪ Both ELACs are normally active. Should one fail, the remaining ELAC automatically assumes all ELAC-related functions.
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.
Flight Control Laws.
❇️Normal Law:
▪ Defines the Flight Control Computers’ logic of the aircraft’s pitch, roll, and yaw limits during normal operations.
▪ All protections are available in order to prevent the aircraft from exceeding its designed flight envelope. Active when all, or nearly all, systems are functioning correctly.
Flight Control Laws.
❇️ Alternate Law:
▪ Defines the Flight Control Computers’ logic of the aircraft’s pitch, roll, and yaw limits in response to multiple failures involving a Flight Control computer, Hydraulic, or Navigation system/s (ADIRS).
▪ Maintains a high level of capability, though some flight control characteristics change, and some flight envelope protections are lost.
Flight Control Laws:
❇️Direct Law:
❇️Typically occurs as the result of the landing gear lowered while in Alternate Law but, can also be the result of more significant system failures.
▪ Flight control feel, and response is like a conventional aircraft but, all protections are lost.
Flight Control Laws
❇️Mechanical Backup Law:
▪ Occurs when all flight control computers have failed or there has been a total loss of electrical power.
▪ Side sticks are inoperative, and the aircraft can only be controlled by manual pitch trim, rudder pedals and engine thrust.
Flight Control Laws
❇️Abnormal Law:
▪ Provides sufficient control to recover from unusual attitudes as the result of extraordinary external event.
▪ Is a subset of Alternate Law.
Describe Load Factor Demand.
▪ Available in Normal and Alternate Law.
▪ Flight control computers interpret pitch change commands as G-load changes:
• Climb commands (Stick aft) result in a positive G-Load change
• Descent commands (Stick forward) result in negative G-Load change
• Neutral stick results in zero G-Load change
Describe Automatic Pitch Trim during a roll.
▪ Automatic pitch trim is provided by the ELACs in Normal and Alternate Law.
▪ Pitch trim is automatically provided for bank angles up to and including 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 configuration (Flaps and Slats retracted): -1.0g to +2.5g
• Slats extended, and Flaps retracted: -1.0g to +2.5g
• Slats and Flaps extended: 0.0g to +2.0g
Describe Pitch Protection.
▪ Available only in Normal Law.
▪ Prevents excessive nose-up and nose-down attitudes.
▪ ELACs will allow attitudes no greater than 30º nose-up, or 15º nose-down, even if the sidestick is held full aft/forward.
Describe High Speed Protection.
▪ Available only in Normal Law.
▪ Attempts to prevent aircraft from exceed VMO/MMO.
▪ Autopilot automatically disengages.
▪ ELACs automatically pitch the aircraft up to limit further acceleration, even if the sidestick is held full
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.
▪ 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.
▪ Alpha Prot is represented by the position of the top of the amber and black band.
▪ Is available only in Normal Law.
▪ It can be overridden with aft side stick movement.
Describe Alpha Max and how it is indicated on the airspeed indicator.
▪ Alpha Max is the highest angle of attack (AOA) that the flight control computers will allow:
❇️Available only in Normal Law.
❇️It cannot be overridden by the pilot even with full aft sidestick pressure.
▪ It is represented by the top of the red band on the airspeed indicator.
Describe roll rate in Normal Law.
▪ Full sidestick deflection yields the maximum allowable roll rate of 15º per second, regardless of airspeed or configuration.
▪ Deflecting a sidestick only halfway yields a roll rate half of the maximum allowable rate.
▪ Neutral sidestick commands a zero change in roll rate.
Describe Bank Angle Hold
Only available in Normal Law. Bank Angle Hold - At commanded bank angles of ≤33º, the bank angle is maintained with automatic pitch trim when sidestick is released.
Describe Positive Spiral Static Stability.
❇️Only available in normal law.
Positive Spiral Static Stability - At commanded bank angles of >33º, if the sidestick is released, bank angle returns to and maintains 33º. Continuous pressure must be applied to the sidestick to hold bank angles exceeding 33º as well as pitch.
Describe the role of Automatic Pitch Trim during turns.
▪ Available in Normal and Alternate Law.
▪ At bank angles ≤33º, the ELACs automatically introduce the necessary back pressure through automatic pitch trim.
▪ At bank angles above 33º, this feature becomes inhibited, and aft sidestick will be necessary to maintain a level turn.
Describe Bank Angle Protection.
▪ Available only in Normal Law.
▪ ELACs restrict bank angle to a maximum of 67º, even if full left or right sidestick is maintained
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 mode of Normal Law.
❇️Ground Mode:
• Active when aircraft is on the ground.
• Direct relationship between the sidesticks and flight control surfaces
• Permits pilot to perform a flight control check and rotate the aircraft on takeoff.
Describe the Flight mode of Normal Law.
❇️Flight Mode:
• Active shortly after takeoff.
• All flight control computer protections and flight characteristics take effect.