Flight Controls. FCTRL Flashcards
What are the roles of the Elevator Aileron Computers(ELAC1 and ELAC2)?
- Control of elevators, ailerons, trimmable horizontal stabilizer(THS)
- Determines requirement for and activated spoiler assist during rolls, and rudder input for yaw
- Both are normally active. If one fails the remaining one assumes control automatically for the other one
What are the roles of the Flight Augmentation Computers(FAC 1 and FAC2)
1 Control of rudder including Turn coordination Yaw damping High/low speed rudder Limiting Rudder Trim 2. Only one FAC is active at a time with the other one a backup
What are the roles of the Spoiler Elevator Computers?(SEC1, SEC 2, SEC3)
- All SECs are active with each responsible for a specific pair, or pairs, of spoiler panels
- SEC1 and SEC2 can provide backup of the elevators and THS in the event of a dual ELAC failure
Describe normal law
- FCCs logic of the aircrafts pitch roll and yaw limits during normal ops
- ALL protections are available to keep aircraft in design envelope.
- Active when all or nearly all systems are functioning properly
Describe alternate law
- FCCs logic for pitch, roll, and yaw limits in response to system failures involving the FCC, hydraulic, or NAV systems(ADIRS)
- Some flight control characteristics change
- Some flight envelope protections are lost
Describe Direct Law
1 typically as a result of the landing gear being lowered while in Alternate Law but can be the result of more significant failures
- Flight control feel, and response is like a conventional aircraft
- All protections are lost
Describe Mechanical Backup Law
- Occurs when all FCCs have failed or total loss of electrical power
- Inoperative side sticks
- Only controlled by manual pitch trim, rudder pedals, engine thrust
Describe Abnormal Law
- Provides sufficient controls for unusual attitudes
2. A subset of Alternate Law
Describe Load Factor Demand
What’s Law/s is it available?
- Available in Normal and Alternate Law
- FCCs interpret pitch change command as G loading
A. Climb commands(stick aft) result in a
Positive G load change
B. Descent commands(stick forward)
Result in negative G load
C. Neutral Stick result in 0 G loading
Describe automatic Pitch Trim during a roll
Which law/s is it available
- Automatic pitch trim is provided by the ELACs in Normal AND Alternate mode
- Automatically provided for pitch trim up to 33 degrees
Describe Maneuver Protection
Available in which Law/s
- Available in Normal and Alternate modes
- Restricts flight control movement that exceed its designed structural G loading
A. Clean = -1.0g to 2.5g
B. Slats extended/flaps retract = -1g to 2.5g
C. Slats and flaps extended = 0g to 2.0g
Describe pitch Protection
Available in which Law/s?
- Available ONLY in Normal Law
- Prevents excessive nose up or nose down attitudes
- ELACs will allow attitudes no greater than 30* nose up and 15* nose down
Describe high speed protection
Available in which Law/s?
- Only in Normal Law
- Attempts to prevent aircraft from exceeding VMO/MMO
- Autopilot automatically disengaged
- ELACs auto pitch the aircraft up to limit acceleration regardless of stick position
Describe Alpha Protection (Alpha Prot.)
Available in which Law/s?
- Normal Law only
- FCCs prevent AOA from exceeding predetermined threshold at low speed
- Auto pilot disengages and speed brakes auto retract
- FCC Load Factor Demand to direct side stick pitch control.
- Pilot side stick input CAN override the FCC and further degrade AOA
Describe Roll Rate Demand
Available in which Law/s?
- Only in Normal Law
- Full sidestick give max roll rate if 15* per second regardless of airspeed or configuration
- Half stick deflection yield half max roll rate
- Neutral side stick commands a zero change in rate
Describe Bank Angle Hold and Positive Spiral Stability
Both roll characteristics are only available in Normal Law
Bank Angle Hold = at bank angles of less than or equal to 33* the bank is maintained with automatic pitch trim when side stick is released
Positive Spiral Stability- at bank angles greater than 33* if sidestick is released the aircraft will auto roll back to 33*
1. Continuous pressure on sidestick to hold bank angles exceeding 33* as well as pitch adjustments
Describe the roll of Automatic Pitch Trim during turns
Available in which Law/s?
- Available in Normal Law and Alternate Law
- At bank angles of 33* or less, the ELACs auto introduce necessary back pressure through auto pitch trim
- At bank angles over 33* the feature is inhibited and aft sidestick will be necessary to maintain a level turn