Flt Controls / Flt Control Laws / MCDU / FMGS Flashcards
What type of flight control system does the A320 family aircraft utilize?
Fly-by-wire system
Describe how the flight controls are controlled and activated
Electrically controlled and hydraulically activated
How is NORMAL LAW indicated on the PFD?
Green “=” for pitch, bank and overspeed limits
Amber/black (ALPHA PROT) airspeed tapes
How is DIRECT LAW indicated on the PFD?
Amber "USE MANUAL PITCH TRIM" Amber Xs (indicating lack of NORMAL LAW protections)
How is MECHANICAL BACKUP indicated on the PFD?
Red "MAN PITCH TRIM ONLY" Amber Xs (indicating lack of NORMAL LAW protections)
When operating in NORMAL LAW in “flight” mode, what does the side stick command for pitch and roll?
Pitch - G load
Bank - Roll rate
How is ALTERNATE LAW indicated on the PFD?
Amber Xs (indicating lack of NORMAL LAW protections)
What is the significance of the Side Stick Priority (Red Arrow) Light?
The other pilot has gained side stick authority
Name the flight control computers and the number of each.
FAC - Flight Augmentation Computer (2)
ELAC - Elevator Aileron COmputer (2)
SEC - Spoiler Elevator Computer (3)
What are some of the ELAC functions?
Normal elevator Normal aileron Normal pitch and roll Alternate pitch Direct pitch and roll Abnormal att Aileron droop Autopilot orders
What are some of the 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
What are some of the FAC functions?
Rudder Trim Rudder travel limit Yaw control Flight envelope protection - vertical Windshear protection Low energy warning protection Alpha floor protection PFD speed scale
What should happen to the THS after landing?
Reset to zero
Describe some of the protections a pilot will have in NORMAL LAW
- High speed
- High Angle of Attack (AOA alpha protection)
- Load fator limitation +2.5G / -1.0G (+2.0G/0.0G with flaps/slats)
- Pitch Attitude (30 up / 15 down)
- Bank Angle (67 degrees)
Describe High Speed Protection
If VMO/MMO plus a predetermined factor is exceeded, the system induces a pitch-up input to limit aircraft speed
What, if anything, can a pilot do to override high-speed protection pitch up?
It is not possible to override a protection while still in NORMAL LAW. In this case the aircraft would need to be forced into ALTERNATE LAW (by turning 2 ADRs off, for example)
What is ALPHA MAX?
The maximum angle of attack allowed in NORMAL LAW, indicated by the top of the red strip on the airspeed scale.
How does high angle of attack protection operate?
When the angle of attack exceeds ALPHA PROT, pitch trim ceases and angle of attack is now proportional to side stick deflection, not to exceed ALPHA MAX even with full aft side stick deflection.
What protections, if any, does a pilot have in ALTERNATE LAW?
Load factor
High speed stability
Low speed stability
What protections, if any, does a pilot have in DIRECT LAW?
none
When, if at all, does flare mode activate in ALTERNATE LAW? Describe the whole process.
No flare mode in Alternate Law
Aircraft proceeds directly from Alternate Law to direct law when the gear is selected down and flare mode will not be available
If in alternate law, when will the aircraft revert to DIRECT LAW?
If the controls degrade to alternate law for any reason other than recovery from abnormal attitude, direct law automatically becomes active with gear extension and autopilots not engaged. In this case, full use of autopilot is recommended until they must be disconnected.
When is there a direct relationship between side stick and flight control surface deflection
When in DIRECT LAW
When below 100 feet
It’s common Airbus philosophy that the Airbus cannot stall in NORMAL LAW. However, there are conditions in which it can. Describe how this can happen.
Faulty Radio Altimeter
A good pilot will operate under the philosophy that anything can happen.
Preventative systems such as (ALPHA PROT, ALPHA MAX, etc.) could
interpret bad data as valid data and subsequently fail to recognize the actual
angle of attack or flight path of the airplane. Therefore, it is hard to point to
exact scenarios when the Airbus can stall in NORMAL LAW. We need to
understand anything is possible and we should recognize stall indications
and recover regardless of the active control law.
After recovery from an unusual attitude, what control law would the aircraft likely be in?
Abnormal Attitude Law
How would the aircraft enter ABNORMAL ATTITUDE LAW?
By exceeding approximately double the NORMAL LAW limits.
What is the purpose of ABNORMAL ATTITUDE LAW?
Allows the aircraft to be recovered from an unusual attitude
If the flight crew is flying at 300 knots and they happen to pull full back on the side stick, how high can the pitch up?
30 degrees up
If the flight crew selected 100 knots on the speed knob, how slow would the aircraft fly?
VLS
Describe, in detail, what would happen if the flight crew slowly pulled the thrust levers to idle.
As airspeed decays, the THS adjusts the pitch attitude to maintain altitude.
If the angle of attack increases to a threshold value, known as ALPHA PROT, the pitch function of the side stick changes. Stick movement commands a specific angle of attack instead of a G load change.
Since auto trimming is inoperative, the pilot must hold continuous back pressure in order to fly slower than the speed for ALPHA PROT.
The side stick no longer provides a “G demand.” Instead, the pilot is requesting a specific angle of attack with the side stick.
Describe what would happen if the flight crew continued to pull back on the side stick (with thrust at idle). How slow would the aircraft go?
The speed corresponding to ALPHA MAX
With the stick full aft, the elevators will adjust the pitch attitude to maintain a maximum safe angle of attack (ALPHA MAX). This maximum angle of attack, induced by the pilot, is slightly lower than the stall angle of attack;
therefore, the aircraft theoretically cannot be stalled in NORMAL LAW.
At some point during this demonstration (pulling thrust levers to idle, then pulled back on stick) the AUTOTHRUST automatically applies TOGA power. What is this protection, and how does it work?
ALPHA FLOOR is a function of AUTOTHRUST. It will activate at any airspeed based on angle of attack and automatically apply TOGA thrust regardless of thrust lever position.
ALPHA FLOOR is available if the AUTOTHRUST is functional (it does not need to be active), an engine is running (not both), and the aircraft is in NORMAL LAW.
Angle of attack protection does not depend on ALPHA FLOOR to function.
On NEO aircraft, ALPHA FLOOR is inhibited above M 0.6
Describe what would happen if a flight crew attempted to overstress the aircraft while in NORMAL LAW.
Maneuver protection prevents a pilot from over stressing the aircraft by limiting flight control inputs.
If G loads become greater than normal, they are displayed in amber on the lower ECAM above the digital clock.
When the side stick is pushed forward, less than 1G is commanded. A given pitch input always results in the same pitch response regardless of airspeed.
When the stick is returned to neutral, the new pitch is held constant regardless of airspeed changes.
What are the main components of the FMGS?
2 FMGCs
2 MCDUs
1 FCU
2 FACs
What are the functions of the FMGCs?
Flight Guidance
Flight Management
What are the three modes of FMGC operation?
Independent
Single
Dual
What are the two modes of flight guidance?
Managed Guidance
Selected Guidance
What is the managed mode of flight guidance used for?
Long-term lateral, vertical, and speed profiles as determined by the FMGS.
What is the selected mode of flight guidance used for?
Temporary lateral, vertical, and speed commands as selected with the FCU.
Does selected or managed guidance have priority?
Selected guidance
What does ACTIVATE/CONFIRM APPR phase do for the pilot?
Allows thrust and speed target to follow a predetermined schedule, based on flap selection:
- FO = green dot
- F1 = S speed
- F2 = F speed
- F3 = F speed or VAPP (depending on landing flap selection)
- F4 = VAPP
If using managed speed, GSmini is available. If using selected speed, GSmini is not available.
What type of database is periodically updated in the FMGS?
Navigation database
Can the crew modify data in the navigation database?
The crew has limited ability to create pilot stored navigational data.
How would a flight crew determine the validity of the navigation database?
On the A/C STATUS page.
What input does each FMGC normally use for position determination?
A hybrid IRS/GPS position.
What is the normal operational mode of the FMGS?
Dual mode, with on eFMGS as master and the other FMGS as slave.
How does autopilot selection influence master FMGS logic?
If one autopilot is engaged, the respective FMGS is master
If both autopilots are engaged, FMGS 1 will be the master
If no autopilot is engaged, FMGS 1 is the master
If an amber OFF SIDE FM CONTROL message is displayed on the ND, what action should the crew take?
An FMGS has failed and both NDs must be set to the same mode and range. The full procedure can be found in the COM.
In cruise flight with AP1 engaged, what would happen if AP2 was selected?
AP2 would take over, and AP1 would disengage. It is only possible to engage both autopilots in the approach phase after selection of the APPR pushbutton.
What is the difference between the large and small fonts utilized in the MCDU?
Large - Pilot entries and modifiable data
Small - Default or computed, non-modifiable data
When would a Takeoff Shift be entered on the PERF TO page?
When takeoff begins at a runway intersection with NO GPS PRIMARY
If the FLEX TEMP is not entered on the TAKEOFF page of the MCDU, and the thrust levers are positioned in the FLEX detent, what will occur and what should be done?
A warning will be generated
Thrust levers should be moved into the TOGA detent and a max thrust takeoff should be accomplished.
Where would a pilot enter the Zero Fuel Weight?
INIT B page
What do amber box prompts on the MCDU indicate?
An entry is mandatory
What occurs when managed NAV mode is engaged and the aircraft flies into a flight plan discontinuity?
NAV mode will be lost and the HDG/TRK mode engages.
What is the bank angle limited to if either high-speed protection and angle of attack protection are active?
45 degrees
What is VLS?
Velocity lowest selectable
It is possible to SELECT a speed lower than VLS
MANAGED speed lower than VLS is not possible
In landing config, equal to VREF in other aircraft.
Lowest speed FDs and A/THR will allow
What is VAPP?
VLS adjusted for winds
What is GSmini?
Minimum ground speed
Purpose - Maintain a minimum energy state
Only available in MANAGED speed
Equals VAPP minus headwind component entered on PERF APPR
Never less than VAPP or greater than VFE
