Flight Control Computers
2 ELACs
- Elevator Aileron Computers
3 SECs
- Spoiler Elevator Computers
2 FACs
- Flight Augmentation Computers
Elevator Aileron Computer
ELAC functions
- normal elevator
- normal aileron
- normal pitch and roll
- alternate pitch
- direct pitch and roll
- abnormal att
- aileron droop
- autopilot orders
Spoiler Elevator Computer
SEC functions
- normal roll
- speed brakes
- alternate pitch
- direct pitch
- direct roll
- abnormal attitude
What does SEC 3 control
- Spoiler control - one flight spoiler and one ground spoiler on each wing.
Flight Augmentation Computer
FAC functions
- rudder trim
- rudder travel limit
- yaw control
Flight Envelope Protection
- Windshear Protection
- Low Energy Protection
- Alpha Floor Protection
- Characteristic PFD speeds
FCDC
Flight Control Data Concentrator
There are 2, and they aquire data from the ELACs and SECs and send it to the EIS and CFDS.
Normal Law protections
- High Speed
- High AOA
- Load Factor +2.5G / -1.0G clean (+2.0G / 0.0G with flaps/slats)
- Pitch 30° up / 15° dn
- Bank 67°
Alternate Law protections
- load factor
- high speed stability
- low speed stability
How is DIRECT LAW indicated on the PFD?
“USE MANUAL PITCH TRIM”
(in amber)
Amber Xs
(indicating lack of Normal Law protections)
How is MECHANICAL BACKUP indicated on the PFD?
“MAN PITCH TRIM ONLY”
(in red)
Amber Xs
(indicating lack of Normal Law protections)
DIRECT LAW protections
none
How are the flaps and slats affected if only GREEN hydraulic pressure is available?
Flaps and slats will still operate, but at half speed.
What prevents flap or slat asymmetry?
Wing Tip Brakes
If WTBs activate due to a flap asymmetry, how are the slats affected?
Slats can still operate normally, only flaps are inhibited.
What is ALPHA LOCK?
This function inhibits slat retraction from 1 to 0 with a high AOA and low airspeed.
What happens to the ailerons when the flaps are extended?
The ailerons droop
When will the ground spoilers automatically retract?
During a touch and go or balked landing with at least one thrust lever above 20%
What conditions will inhibit speed brake extension?
active AOA protection
Thrust levers above the MCT detent
ALPHA FLOOR
What happens to the THS after landing?
Resets to zero
Abnormal Alternate Law
Triggered by exceeding approximately double the NORMAL LAW limits
Allows the aircraft to be recovered from an unusual attitude
ALPHA MAX
The maximum angle of attack allowed in NORMAL LAW, indicated by the top of the red
High AOA Protection
When the AOA exceeds ALPHA PROT nose up trim ceases and AOA is now proportional to side stick deflection, not to exceed ALPHA MAX even with full aft sidestick.
How are the flight controls controlled and actuated?
Electronically controlled and hydraulically actuated
How is NORMAL LAW indicated on the PFD?
Green = for pitch, bank and overspeed limits, and amber/black (ALPHA PROT) airspeed tape
