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Flight Controls Flashcards

1
Q

The flight control system uses seven flight control computers which include:

A
  • 2 Elevator Aileron Computers (ELACs)
  • 3 Spoiler Elevator Computers (SECs)
  • 2 Flight Augmentation Computers (FACs)

FAC 1 becomes inoperative when the aircraft electrical supply is in a batteries-only configuration.

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2
Q

If both ELACs have failed or are selected OFF:

A
  • The flight control laws degrade from normal to alternate
  • Both ailerons are inoperative and roll control is provided by the spoilers
  • Elevator and THS control is provided by the SECs
  • Both autopilots will be inoperative
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3
Q

What are the purpose of the SECs?

A

The spoilers are controlled in pairs by the SECs so that a single failure does not result in an asymmetric flight control configuration.

SECs 1 and 2 also provide backup elevator and THS control should both ELACs fail.

SEC 3 does not provide any backup control.

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4
Q

If all three SECs have failed or are selected off:

A
  • The speed brakes and spoiler panels are all inoperative and roll is controlled by ailerons only
  • The ability of the SECs to provide backup pitch control is lost
  • Flight control laws degrade from normal to alternate
  • Autopilot remains operational since the primary flight controls are receiving inputs from the ELACs and FACs
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5
Q

If both FACs have failure or are selected OFF:

A
  • Rudder control is through the rudder pedals via mechanical connection
  • Rudder trim, yaw damping, and rudder limiting are lost
  • Flight control laws degrade from normal to alternate
  • Both autopilots will be inoperative

Only one FAC controls the rudder at a time, the other serves as a backup. All three rudder servos are powered by separate hydraulic systems.

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6
Q

Turn coordination is computed by the _____, which send yaw information to the controlling _____ to actuate the rudder servos.

A

ELACs, FAC

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7
Q

How is rudder travel limited at higher speeds?

A

The FACs use airspeed information from the ADIRUs to limit the amount of available rudder travel at higher speeds as deflection produces excessive airframe loads.

Rudder travel is unrestricted below 160 kts in the A320.

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8
Q

Speedbrake extension is inhibited, and any extended panels will automatically retract if:

A
  • Flaps FULL are selected
  • If TOGA thrust is applied
  • If certain high AoA situations are encountered
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9
Q

Ground Spoilers are automatically extended during an RTO when:

A
  • When armed, wheel speed exceeds 72 kts and thrust levers are set to idle
  • Even when disarmed, wheel speeds exceed 72 kts and at least one thrust lever is set to reverse and the other lever set to idle
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10
Q

Ground Spoilers are automatically extended during landing when:

A

During landing, either armed or not in the RET position:
* Both main landing gears are on the ground
* Both thrust levers are at idle, OR reverse is selected on at least one engine, with the other lever being below MCT

During landing, disarmed:
* Both main landing gears are on the ground
* Reverse is selected on at least one engine, with the other lever being below MCT

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11
Q

How would the flight crew manually extend the ground spoilers on the ground?

A

It is possible to manually extend the ground spoilers on the ground by moving the SPEED BRAKE lever aft, however only panels 1 through 4 extend.

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12
Q

What is the purpose of the SFCCs?

A

The SFCC monitors the position of the slats and flaps which enables them to respond to asymmetry, uncommanded movement, or runaway situations.

After an SFCC failure, the remaining SFCC is able to control the remaining unaffected motors to operate the slats and flaps, but only at approximately half their normal speed.

Each SFCC controls one hydraulic motor to extend the slats and one to extend the flaps.

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13
Q

What is the purpose of the WTBs?

A

The WTBs are used to lock the appropriate drive train to prevent further movement in an asymmetry situation as well as during uncommanded movement of slats or flaps.

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14
Q

Slat Alpha/Speed Lock engages if the slats are extended and:

A
  • The AoA, or alpha, becomes excessive, or
  • Airspeed gets too low
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15
Q

All five spoiler panels on each wing are used to perform the ground spoiler function. The bracket markings on the F/CTL page remind you that:

A
  • The 3 middle spoiler panels carry out the speedbrake function
  • The outer four spoiler panels assist in roll control
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16
Q

What are the Normal Law pitch attitude protections?

A

Pitch Attitude - 30 degrees (CONF 0 to 3), reduced to 25 degrees at low speed. Or 25 degrees (CONF FULL), reduced to 20 degrees at low speed. 15 degrees nose down.

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17
Q

What are the Normal Law High Speed protections?

A

High Speed - Protection limit by green equals on speed tape. The autopilot will disconnect at VMO + 15 / MMO + 0.04. This protection does not prevent the aircraft from exceeding VMO/MMO. Bank angle limit is reduced from 67 to 40 degrees.

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18
Q

What is the maximum rate of roll in Normal Law?

A

The ELACs limit a roll to a maximum of 15 degrees per second in normal law.

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19
Q

What is Ground Mode in Normal Law?

A

Ground Mode:
* Control surface deflection is proportional to sidestick and rudder pedal movement.
* Allows for a flight control check and rotation on takeoff.
* Automatic pitch trimming is inhibited.

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20
Q

What is Flare Mode in Normal Law?

A
  • Exists to give the landing flare and touchdown a conventional feel.
  • At 50 feet RA, the system memorizes the current pitch attitude.
  • Beginning at 30 feet, the system begins to reduce the pitch attitude to negative two degrees nose down over a period of 8 seconds.
  • Shortly after landing, Ground Mode again becomes active and the THS automatically resets to 0.
  • In the event of a go-around, the transition from Flare to Flight Mode occurs above 50 feet.
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21
Q

Can the speedbrakes be used in Direct Law?

A

Speedbrakes should be used with caution, allowing time to make manual pitch trim corrections.

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22
Q

What do the FACs provide in Direct Law?

A

Yaw damping no longer functions, however rudder limiting and trimming continue to function as long as one FAC is operable.

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23
Q

What is the purpose of Abnormal Attitude Law?

A

Ensures that the flight control laws do not prevent or interfere with recovery from an abnormal flight attitude.

The same as Alternate Law without automatic pitch trim, yaw damping or protections, except load-factor demand is maintained. Automatic pitch trim and yaw damping are restored after recovery.

Abnormal Attitude Law engages when:
* Bank angle exceeds 125 degrees
* Pitch attitude exceeds 50 degrees nose up or 30 degrees nose down
* Airspeed is below 60 to 90 knots (dependant on pitch attitude), or above 440 knots
* Mach exceeds 0.91
* Angle of attack above 30 to 40 degrees, or below -10 degrees

This is the only case where the flight control laws will remain in Alternate Law after the landing gear is extended.

Recognizing that the flight control computers may have been subjected to conditions that they are not normally designed for, the system is prevented from upgrading back to Normal Law.

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24
Q

When would Mechanical Backup Control become active?

A

Available in the unlikely event that a total loss of the electrical system has occurred, or significant failures have occurred in the flight control system, such as a loss of five FBW computers, a loss of both elevators, or the total loss of ailerons and spoilers.

Allows you to maintain aircraft control until a higher law can be restored.

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25
Q

What aircraft controls are available in Mechanical Backup?

A

Pitch is controlled by using the pitch trim wheels. Yaw and roll are controlled using the rudder pedals which are mechanically connected to the rudders hydraulic servos. Limited pitch and roll control can be accomplished by using differential thrust.

26
Q

What is PLD?

A

Phased Lift Dumping (PLD) is designed to help the aircraft settle onto the runway during crosswind landings or landings on wet or contaminated runways.

27
Q

If the ground spoilers are armed, when will PLD deploy?

A

Speed brake lever not in the retracted position or ground spoilers armed and:
* One main landing gear on ground,
* Both thrust levers at or below Idle position.

Ground Spoilers will automatically retract if the thrust levers are advanced beyond 20 degrees TLA.

28
Q

If the ground spoilers NOT are armed, when will PLD deploy?

A

Speed brake lever in the retracted position, but ground spoilers not armed and:
* One main landing gear on ground,
* Reverse selected on at least one engine (and the other thrust lever below MCT position).

Ground Spoilers will automatically retract if the thrust levers are advanced beyond 20 degrees TLA.

29
Q

PLD will also deploy to reduce bounce severity in the case of inappropriate thrust handling. Ground spoilers are also partially deployed when the following conditions are met:

A
  • Ground spoilers armed,
  • Both main landing gears on ground,
  • Both thrust levers at or below the Climb position.
30
Q

What is Positive Spiral Static Stability?

A

Inside the normal flight envelope, the system maintains positive spiral static stability for bank angles above 33°. If the Pilot releases the sidestick at a bank angle greater than 33°, the bank angle automatically reduces to 33°.

31
Q

Positive Spiral Static Stability angles:

A

Normal: Max of 67°, returns to 33°
Angle-of-Attack or Pitch Attitude Protection: Max of 45°, returns to 33°
High Speed Protection: Max of 40°, returns to 0°

When bank angle protection is active, auto trim is inoperative.

32
Q

When is automatic trim not available?

A
  • Abnormal Attitude Law
  • Direct Law
  • Mechanical Backup
  • Bank Angle Protection
  • On the Ground

Nose-up or down trim is inhibited during high speed and high AoA protection.

33
Q

What are the SDACs?

A

The two identical SDACs acquire data, then generate signals. Some of these signals go to the three DMCs, which use them to generate displays of system pages and engines parameters. Others go to the flight warning computers, which use them to generate ECAM messages and aural aural alerts.

34
Q

What are the FCDCs?

A

Flight Control Data Concentrators (FCDC) acquire data from the ELACs and SECs and send it to the electronic instrument system (EIS) and the centralized fault display system (CFDS).

35
Q

What is Rotation Mode?

A

The objective of the Rotation Mode is to provide homogeneous rotation for all possible weight, CG, and configurations, while minimizing the risk of a tailstrike. The Rotation Mode is a pitch rate demand control law, providing tailstrike protection.

The Flight Crew can override the tailstrike protection. The Rotation Mode is Active from 70 kt during takeoff roll until 10 sec after lift-off.

36
Q

What does sidestick deflection control for pitch?

A

Pitch is controlled by a rate of change for load factor.

37
Q

What occurs when reaching alpha prot?

A

ASAP:
AP Off
Spoilers Retract
Sidestick Controls AoA
Further Pitch Up Trim Inhibited

38
Q

When does Alpha-Floor activate?

A

The Alpha floor function automatically applies TOGA thrust, when the angle of attack exceeds the Alpha floor threshold (between αPROT and αMAX) OR pitch attitude or AoA protection is active with the sidestick close to full aft.

39
Q

How is pitch and bank commanded in Alternate Law?

A

Load factor for pitch and bank is direct.

40
Q

Are stabilities overrideable in Alternate Law?

A

Yes, but pitch trim is inhibited.

41
Q

Is it possible to get into Direct Law without entering Alternate Law?

A

Yes, depending on failures.

42
Q

How long must the pilot hold the sidestick takeover pb to disconnect the other sidestick?

A

40 seconds

43
Q

What are the SFCCs?

A

The slat and flap surfaces are controlled by two Slat and Flap Control Computers which are also known as SFCC 1 and SFCC 2. Each SFCC has two channels. One channel controls the slats and one channel controls the flaps.

44
Q

What speed do the flaps in CONF 2 auto retract at?

A

210 knots

45
Q

What is the Alpha/Speed Lock Function?

A

This function inhibits slat retraction at high angles-of-attack and low speeds. The SFCCs use corrected angle-of-attack (alpha) or airspeed information from the ADIRUs to inhibit slat retraction.

When the FLAPS lever is set to 0, the slats alpha/speed lock function activates and inhibits
slats retraction, if:
- The AOA is above 8.5 ° or
- The speed is less than 148 kt.

Once the slats alpha/speed lock function is active, the slats retract to 0 when:
- The AOA is less than 7.6 °and
- The speed is above 154 kt

If the FLAPS lever is already set to 0, when either of the above conditions occurs, the function will not activate, therefore, the slats will continue to retract or will remain at 0.

46
Q

Is there any time that the speed brakes would be extended asymmetrically without failure?

A

In order to assist in roll commands

47
Q

When are speedbrakes inhibited?

A

SAAFET:
* SEC1 and SEC3 both have faults., or
* Angle-of-attack protection is active, or
* Alpha floor activation, or
* Flaps are in configuration FULL, or
* An elevator (L or R) has a fault, or
* Thrust levers above MCT position, or

48
Q

When is speedbrake retraction slowed?

A

When the aircraft is flying faster than 315 knots or Mach 0.75 with the autopilot engaged, the speedbrake retraction rate is reduced (Retraction from FULL to CLEAN takes about 25 seconds).

49
Q

What is the purpose of drooping the ailerons?

A

The Airbus A320 is equipped with drooping ailerons, which are a type of high-lift device that enhances the lift produced by the wings during takeoff and landing. The ailerons extend 5 degrees down when the flaps are extended (aileron droop). The drooping ailerons are part of the aircraft’s overall high-lift system, which also includes the flaps and slats.

50
Q

What is Aileron Anti Droop?

A

Allows the ailerons to act as additional spoilers.

51
Q

After which comuper failure would you lose A/THR?

A

FMGC

52
Q

When is Alternate Law entered?

A

If Multiple Failures of Redundant Systems occur, the flight controls revert to Alternate Law.

53
Q

If both ELACs fail, the ailerons revert to the _____ mode.

A

Damping

54
Q

ELAC 1(2) performs the following functions:

A
  • Normal pitch and roll
  • Alternate pitch
  • Direct pitch and roll

Additionally:
* Abnormal attitude
* Aileron droop
* Load Alleviation Function (if installed)
* Acquisition of autopilot orders.

55
Q

Which computers control the THS?

A

ELACs

SECs 1 and 2 will also control the THS in case of ELAC failure.

56
Q

SEC 1(2)(3) performs the following functions:

A
  • Normal roll (by controlling the spoilers)
  • Speedbrakes and ground spoilers
  • Alternate pitch (SEC 1 and SEC 2 only)
  • Direct pitch (SEC 1 and SEC 2 only)
  • Direct roll

Additionally:
* Alternate LAF (if installed)
* Abnormal attitude.

57
Q

Both FACs perform the following functions:

A
  • Normal roll (coordinating turns and damping dutch roll)
  • Rudder trim
  • Rudder travel limit
  • Alternate yaw
58
Q

Both FACs perform the following functions:

A
  • Normal roll (coordinating turns and damping dutch roll)
  • Rudder trim
  • Rudder travel limit
  • Alternate yaw
59
Q

What are the some examples of multiple redundant systems failing?

A

ADIRS, Flight Control Computers, Hydraulics, Electrics

60
Q

When is High Speed and Low Speed Stability present?

A

In Alternate Law

High and Low Speed Stabilities are not always present in Alternate Law.

indoc (80 decks)

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