22 Autoflight / Protections Flashcards
What are the differences between TOGA LOCK, THR LOCK, and LVR ASYM?
TOGA LOCK: When aircraft leaves alpha-floor condition. Remove by disconnecting autothrust.
THR LOCK: Thrust levers in CLB detent (or MCT in OEI) and with an involuntary disconnection (failure or A/THR pb on FCU pressed). Move thrust levels to regain control.
LVR ASYM: Only with two engines, when one thrust level is in CLB or MCT/FLX and the other is not.
What is the alpha lock function?
Inhibits slat retraction at high AOA
When does the autoland warning light illuminate? (8)
- at least one RA indicates a height below 200 ft
- at least one AP is engaged with LAND or FLARE on FMA
- at least one of the following:
- LOC deviation exceeds 1/4 dot and aircraft is above 15 ft RA
- GLIDE deviation exceeds 1 dot and the aircraft is above 100 ft RA
- loss of LOC above 15 ft RA
- loss of GLIDE above 100 ft RA
- difference between RAs over 15 ft
- last AP disengages
- FMGS detects long flare
- FMGS detects untimely flare
FMS can calculate position by 3 different methods. What are they?
MIX IRS:
• average position of the 3 IRS positions calculated by accelerometers
Radio:
• position based on precise radio fixes
GPS:
• exact position calculated by 2 GPS satellites
The a/c will use most accurate which is GPS
What is meant by position BIAS?
It’s added to the mix IRS position using the GPS or radio position so that if GPS is lost, it has an accurate starting position
When does the energy circle display on the ND? What is it?
Appears in HDG/TRK mode
Shows distance required to complete a landing from present position
How does FMS detect engine out condition?
• Engine master switch OFF
• Engine N2 below idle
• one thrust lever below 5* and the other above 22*
• FADEC detects engine fault
If EO CLR is pressed by mistake what happens?
System assumes 2 engine ops again and single engine performance figures cannot be recovered
What is EO REC MAX calculation based on?
Aircraft weight
It’s the max altitude a/c can fly with MCT set and maintain level flight
How many channels does auto thrust have?
2…one per FMGC
When does THRUST LOCK appear and how do you recover?
Only occurs when thrust levers are set in CLB or MCT gate and auto thrust is on.
Move thrust lever donuts to where the actual thrust is
What is RETARD mode?
Active during auto land when idle thrust is commanded and activates at 40ft. Calls out RETARD at 20ft on manual landing and 10ft on auto land
How many FACs are there? What functions do they perform?
2 FACs
• yaw functions (damping, turn coordination, rudder travel limiter)
• low energy warning
• windshear detection
• PFD speed scale & speed calculations
• flight envelope calculations
Load Factor protection values?
+2.5G to -1G CLEAN
+2G to 0G CONFIGURED
Pitch Attitude protections in normal situations and in low speed / high alpha?
Normal situations..
Config 0-3…… +30 to -15
Config full…….+25 to -15
High alpha / low speed
0-3. +25
Full. +20
In pitch when do FD bars disappear/reappear?
Disappear +25 or -13
Reappear +22 or -10
Describe AoA protection
Once speed reduces into Amber barber pole it goes beyond A PROT which changes flight control law to direct. Beyond this at some point A FLOOR activates which gives full power from engines. The pitch will not go beyond A MAX therefore providing max climb angle
If side stick released at A MAX what will happen to pitch?
Attitude returns to A PROT
When does AP disconnect in AoA protection?
A PROT + 1*
What does AoA give protection against?
Windshear and stalling
What is alpha floor and when does it activate?
Athr function that activates at certain point below alpha prot
It commands TOGA
Available from lift off to 100ft above landing
How do you recover from Alpha Floor?
Clicking the instinctive PBs on the thrust levers. Put the thrust levers in the climb gate and re-engage A/THR on the FCU
If you hold the instinctive PBs on the thrust levers for 15s what happens?
Disengage ATHR until the end of the flight. A FLOOR not available
Is alpha floor available in alternate law?
No
How does high speed protection work?
If full forward side stick is applied, the a/c will exceed Vmo/Mmo.
The a/c will neutralise the side stick and then command a nose up pitch until the speed reduces to normal
What happens to bank when high speed protection is active?
Max bank angle 40*
Bank returns to 0 if side-stick released
Centring Beta target in SE conditions provides what?
Minimum drag and best climb performance
How does bank angle protection work?
Bank angle limited to 67, when above 33 and side stick released, bank returns to 33*
How is level flight maintained in bank up to max bank angle?
Up to 33* auto trim will maintain level flight. Above 33* back pressure on sidestick is required to maintain level flight
Is there any relationship between BA protection and the others?
If AoA protection active, max BA will not exceed 45*
If high speed protection active, will not exceed 40* and will return to 0 when sidestick released
What is the low energy warning?
Low energy warning below 2000ft in flaps 2, 3 or Full so pilot can take appropriate action before A FLOOR
When is low energy warning inhibited?
• below 100ft RA
• when TOGA is set
• during EGPWS
• Dual Rad Alt Fail
What is Alpha Lock?
Prevents slat retraction at high attitudes and low speeds.
When is reactive wind shear available?
- At T/O: 3 sec after lift off - 1300ft RA
- At LDG: from 1300ft RA - 50ft RA
- At least config 1 selected
When is predictive wind shear available?
- Below 2300ft RA
- Warnings or Cautions below 1200ft RA
- At T/O inhibited: 100kts - 50ft RA
- At LDG inhibited: Below 50ft RA
What controls the windshear detection system?
When is it active, and under what config?
The windshear detection function is provided by the Flight Augmentation Computer (FAC) in takeoff and approach phase in the following conditions:
At takeoff, 3 s after liftoff, up to 1 300 ft RA
At landing, from 1 300 ft RA to 50 ft RA
With at least CONF 1 selected.
What would you expect to see and hear if you experienced windshear?
The warning consists of:
A visual “WINDSHEAR” red message displayed on both PFDs for a minimum of 15 s.
An aural synthetic voice announcing “WINDSHEAR” three times.
How do the FAC’s detect windshear?
The FACs generate the windshear warning whenever the predicted energy level for the aircraft falls below a predetermined threshold.
In computing this energy level prediction, the FACs use data from different sources. From ADIRS comes data such as vertical speed, air and ground speeds and slope.
The FACs express this energy level as an angle of attack and compare it with an angle-of-attack threshold above which windshear conditions are most likely and pilot action is required.
Below what altitude is predictive and reactive windshear available?
Predictive below 2300ft
Reactive below 1300ft
What predictive windshear warnings and cautions can you get?
Warning
W/S AHEAD (red) on pfd
Go around windshear ahead, audio. Or windshear ahead twice for take off.
Caution
W/S AHEAD (amber) on pfd
Monitor radar display, audio.
When are windshear alerts inhibited?
At takeoff, alerts are inhibited above 100 kt and up to 50 ft.
During landing, alerts are inhibited below 50 ft.
What is the difference between alpha floor and toga lock?
How do you get out of Toga lock?
Angle of attack.
Alpha floor changes to toga lock once the angle of attack is reduced.
TOGA lock can only be deselected by disconecting the autothrust.
If you recieve an amber windshear caution:
W/S AHEAD (amber) on pfd
Monitor radar display, audio.
What should you do?
Consider delaying the approach or a divert.
The approach can be continued provided the crew do the following:
Assess the weather severity with the radar display
Consider the most appropriate runway
Select FLAPS 3 for landing, in order to optimize the climb gradient capability in the case of a go-around
Use managed speed, because it provides the GS mini function mini function
The flight crew may increase VAPP displayed on MCDU PERF APP page up to a maximum VLS +15 kt.
If you recieve a predictive GO AROUND WINDSHEAR AHEAD warning what should you do?
Go around unless postive it is spurious.
How does the aircraft compute its position?
Each FMGC computes its position by using its GPS position and its IRS mix position.
3 IRS’s.
The FMGS selects the most accurate position, considering the estimated accuracy and integrity of each positioning equipment.
