Flight Control Laws and Protections Flashcards

1
Q

What is SRS?

A

Speed Reference System.
Controls speed via elevators.
This speed is appropriate to the phase of flight. There’s SRS T/O and SRS G/A, which are very similar.

Target speed for SRS T/O: V2 which blends into V2+10
Target speed for OEI SRS TO: Current speed, limited V2 to V2+15 (so if EFATO, speed target V2)
Target speed for SRS G/A: Speed at engagement or VAPP, WIG

It is also useful for windshear as it has protections built in for pitch which are slightly less than normal pitch protections and a protection that ensures a minimum rate of climb

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2
Q

How many flight control computers do we have and what do they do?

A

2 x FAC
2 x ELAC
3 x SEC {Lots of sex…}

FAC
Rudder, rudder trim, yaw damper, characteristic speeds, protection speeds, speed tape and speed trend arrow, low energy alert, windshear, beta target

ELAC - Elevator Aileron Computer
Normal elevator/stabiliser control, aileron control

SEC - Spoiler Elevator Computer
Spoiler control, standby elevator/stabiliser control

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3
Q

When is Load Factor protection active?
What are the limits?
What’s the benefit of Load Factor protection?

A

Normal and alternate law

+2.5g to -1g clean
+2g to 0g other configurations

Allows pilot to full back stick instinctively e.g. GPWS

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4
Q

What does the low speed tape look like in other laws except normal?

A

VLS in amber
VSW at top of black and red section

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5
Q

What protections are reduced in alternate law?

A

Load factor limitation similar to normal law.

No pitch attitude protection (Amber Xs)

No bank angle protection

Low speed stability:
- VSW replaces VAprot and VAmax
- 5-10kt above VSW, a gentle nose down signal is introduced
- Pilot can override this
- Alpha floor is inoperative

High speed stability:
- Above VMO/MMO a nose up demand is introduced
- Pilot can override this

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6
Q

Normal flight envelope, what is max limit for bank angle?

A

67 degrees

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7
Q

Above what angle of bank is aft sidestick pressure required in a turn?

A

33 degrees

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8
Q

When is alpha floor available?

A

Normal law

From lift-off to 100ft RA before landing

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9
Q

Which protection has priority over all others?

A

High AOA

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10
Q

What does the low speed tape look like in normal law?

A

VLS in amber outline box
VAprot top of amber and black section
VAmax top of red section

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11
Q

If angle of attack protection is active, and the pilot maintains full sidestick deflection, what is the maximum bank angle?

A

45 degrees

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12
Q

If high speed protection is operative, what will the bank angle return to if sidestick released?

A

0 degrees

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13
Q

Pitch attitude protection limitations?

A

Nose Up
30º - CONF 0, 1, 2, 3
25º - CONF FULL

Nose Down
-15º

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14
Q

At what bank angle does the FD disappear?

A

45º

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15
Q

If high speed protection is active, with full lateral sidestick, what will the maximum angle of bank be?

A

40º

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16
Q

What is the only protection you’ll always have in alternate law, regardless of failure?

A

Load Factor Limitation

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17
Q

What does the sidestick demand in pitch in normal law?

A

Load Factor demand

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18
Q

Describe what happens in flare mode

A

Passing 50’ RA (100’ A321) on landing, the THS is frozen and flare mode provides a direct stick-to-elevator relationship.

The system memorises the attitude at 50ft, and at 30ft introduces a nose down demand to reduce the pitch to -2 degrees nose down over a period of 8 seconds. Consequently, a gentle nose up action is required by the pilot.

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19
Q

When does Ground Mode change to Flight Mode in pitch?

What is the difference between Ground Mode and Flight Mode?

A

Flight mode blends in about 5s after lift off when pitch exceeds 8º.

In Ground Mode sidestick has a direct relationship with Elevator, whereas in Flight Mode it is a Load Factor demand.

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20
Q

I’m normal law, when does auto trim stop functioning?

A

When manual trim input
Rad alt below 50ft
Load factors below 0.5g

21
Q

What is lateral ground mode?

A

Roll is direct relationship to sidestick input
During takeoff max deflection of ailerons and spoilers reduce

22
Q

What’s the difference between Normal and Alternate Law? Pitch, roll, landing, protections and speed?

A

Pitch - unchanged - Load Factor Demand
Roll - direct relationship
Landing - no flare law, landing Direct Law CONF 3
Protections - Load Factor unaffected, High Speed and High AoA are downgraded to stabilities, all other protections lost
Speed - Max speed 320kts, no Alpha Floor

23
Q

What’s the difference between Alternate Law With/Without Reduced Protections?

A

Depends on system downgrades
With protections offers High and Low speed stabilities

24
Q

Describe High Speed stability

A

Alternate Law - may or may not be available depending on failure.
Above VMO/MMO a/c pitches up gently but can be overridden by pilot.
Aural Overspeed Warning is available.

25
Q

Describe Low Speed stability

A

Alternate Law - may or may not be available depending on failure.
Approx 5-10kts above VSW, progressive nose down pitch signal introduced. Pilot can override this.

26
Q

How does PFD annunciation direct law?

A

Annunciates USE MAN PITCH TRIM in amber

27
Q

What is mechanical back up?

A

MAN PITCH TRIM ONLY

Purpose is to manage temporary total electrical, computer, elevator, aileron loss
Manually trim THS for pitch and use rudder for roll

28
Q

What is Rotation Mode?

A

NEO only
Homogenous rotation mode for all possible weight and CG
Minimised risk of tail strike
Pitch Rate demand

Ground Mode -> Rotation Mode -> Flight Mode

29
Q

What are the characteristics of Normal Law Flight Mode?

A

Side stick released - 1g, be that in climb, descent or level
Holds altitude in turns up to 33°

30
Q

High AoA Protection.
When does it activate?
With flight crew input, what does AoA increase to?

A

Activates when AoA > αPROT
Without input, system maintains αPROT
Flight crew can increase this to αMAX

When HIGH AoA activated, sidestick input becomes AoA demand

31
Q

High Speed Protection
When does it active?
What happens when it does?
How does the a/c behave in a dive, both with neutral stick and full forward stick applied?

A

Activates at/above VMO/MMO

When activated:
- Positive spiral static stability (side stick released, a/c returns to 0° bank angle rather than 33°)
- Bank angle limited to 40° rather than 67°
- As speed increases above VMO/MMO, nose down authority progressively reduced AND nose up order applied

Behaviour in a dive:
Neutral stick: Slightly overshoots VMO/MMO
Stick forward: Significantly overshoots VMO/MMO; nose down authority reduces to 0 at VMO+16

32
Q

When does High Speed Protection activate and when does the autopilot disconnect in a high speed scenario? At what speed does ECAM display an overspeed warning and at what speed are the green = shown on the speed tape?

A

High Speed Protection Activation: At/above VMO
Autopilot disconnect: VMO+15
ECAM Overspeed warning: VMO+4
Green overspeed = on speed tape: VMO+6

33
Q

What is meant by positive spiral static stability in Normal law?

A

If release side stick at bank angle >33°, system returns to 33°

34
Q

What is the Load Alleviation Function?

A

Upward deflection of ailerons to reduce wing structure loads
Available in Normal Law when clean

35
Q

What is the point of the Beta/Sideslip indicator?

A

How much rudder to apply to achieve best climb performance - ailerons neutral, spoilers retracted

36
Q

What speeds do you have on the speed tape in a) Normal Law and b) Alternate Law?

A

Normal Law:
1) VLS
2) VαPROT
3) VαMAX

Alternate Law:
1) VLS
2) VSW

37
Q

Do you have bank angle protection in Alternate Law?

A

No.
But when AoB >45°, BANK BANK in red on PFD and “BANK BANK BANK”

38
Q

What protections are available in Direct Law?

A

None!

39
Q

In Direct Law, how does the sidestick deflection relate to pitch and roll demand? What about yaw?

A

Pitch - Direct elevator deflection
Roll - Direct aileron/spoiler deflection
Yaw - Direct mechanical link. Turn co-ordination and yaw damping lost.

40
Q

In what law is overspeed, stall warning and alpha floor available?

A

Overspeed - All laws
Stall warning - Alternate and Direct
Alpha Floor - Normal only

41
Q

What are Abnormal Attitude Laws?

A

Provide PF maximum efficiency to to recover normal attitude
When too banked, nose high/low, slow, fast, high AoA
Like Alternate but no protections, including no Load Factor
F/CTL DIRECT LAW and USE MAN PITCH TRIM displayed
After activated but exited, Alternate Law latched

42
Q

What is Alpha Lock?

A

When clean up Flap Lever 1 - > 0 and:
- Too slow
OR
- Too high AoA

Slats stay out & A-LOCK on EWD

43
Q

At what speed do the flaps auto retract?

A

210 kts

After take off, go from CONF 1+F -> CONF 1

44
Q

Describe the CONF 1 vs CONF 1+F logic

A

If below 100kt, in CONF 0, will get CONF 1+F (setting flap before taxi)

If above 100kt, will get just get CONF 1 (on approach, flaps won’t move until select Flaps 2)

45
Q

When does Alpha Floor activate?

A

Between Alpha PROT and Alpha MAX, depending on aircraft configuration and deceleration rate.

Also if full back stick is held with either pitch attitude or angle of attack protection active

46
Q

When is the Low Energy aural alert available?

A

CONF 2, 3, FULL
When between 100’ RA - 2000’ RA
Normal Law only

Inhibited when:
- TOGA selected
- Alpha Floor
- GPWS
- Double Rad Alt fail

47
Q

What happens when you exit Alpha Floor?

A

When out of conditions and >VLS

TOGA LK

Exit by disconnecting A/THR

48
Q

Ground Speed Mini.
What does it do?
When is it available?

A

Ground Speed Minimum

Ensures approach flown at or above set minimum energy level

Active when approach activated and speed managed

49
Q

SLS.
What is it?
What are the benefits?
Can we do it?

A

Check NTC and included references

SBAS Landing System

Allows some RNP approaches to be flown the same way as CAT 1 ILS

European SBAS is EGNOS.

Vertical path is geometric not based on baro - no temp effect

Can be used if:
RNP approach with EGNOS available
Aircraft equipped with SLS - there will be an OFP attachment
easyJet is restricted to LNAV/VNAV minima - don’t use LPV!