AFCS Flashcards

1
Q

What does the AFCS provide?

A
  • autopilot functions
  • yaw dampening functions
  • flight director system
  • altitude alerts
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2
Q

What powers the AFCS computer?

A

DC emer bus

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3
Q

What powers the Advisory Display Unit?

A

DC stby bus

ADU displays advisory and caution messages

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4
Q

What are the servo actuators?

A

Control the aircraft

Consist of an electric motor and clutch assembly that moves the respective flight control surface

Pitch and yaw actuators located in the aft portion

Roll servo actuators located on the aft side of the wing box

Control for servos powered by DC stby bus

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5
Q

How do you engage the autopilot?

A

AP pb on the AFCS control panel

This will automatically engage the yaw damper

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6
Q

How do you disengage the autopilot?

A
  • Pressing the AP pb - this will only disengage AP not the yaw damper
  • pressing AP quick disconnect button on control column
  • using normal or standby pitch trim
  • pressing YD pb on AFCS control panel
  • pressing GA button on the power levers
  • applying force to the rudder pedals or control column
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7
Q

How is the yaw damper engaged/disengaged?

A

The YD pb

AP will be disengaged by disengaging the YD

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8
Q

What mode will the AP be in if no vertical or lateral modes are selected on AFCS control panel?

A

Basic mode - will maintain the pitch at time of engagement and will level the wings and maintain heading at the time the wings levelled

If wings are already level, it will maintain that heading

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9
Q

What will the autopilot do on engagement if vertical and lateral modes are active?

A

It will immediately manoeuvre to follow the active commands

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10
Q

What happens on autopilot engagement if vertical and lateral modes are armed?

A

The autopilot will remain in basic mode until the flight director modes are active

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11
Q

What vertical modes are available?

A

IAS
VS
ALT - altitude hold

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12
Q

How can VS be changed?

A

By the pitch wheel

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13
Q

What lateral modes are available?

A

HDG
NAV
APP
BC - back course

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14
Q

What does the BANK pb do?

A

It will change the max bank angle between HI (27 degrees) and LO (15 degrees)

At initial system power up the max bank angle is set at 27 degrees

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15
Q

When will the AP and YD be disengaged together?

A

By applying a force on the rudder pedals

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16
Q

What aural and visual indications will you get on AP disengagement?

A

Red AP OFF light
Cavalry charge will sound
Arrows adjacent to AP pb will extinguish
RESET pb will illuminate on the ADU
AP DISENGAGED amber message on the ADU

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17
Q

What indications will you get on YD disengagement?

A

Two arrows on either side of YD pb will extinguish
ADU message will show AP/YD disengaged

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18
Q

How can you clear the AP disengagement warnings?

A

By pressing the RESET pb or by pressing the AO disconnect buttons on either control wheel

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19
Q

When will the AP disengage automatically?

A
  • one of the engagement conditions for the AP or YD no longer exists
  • stall warning threshold has been reached
  • there is a disagreement between the two AHRS or ADCs
  • there is a mismatch between the two pitch trim commands
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20
Q

What failures mean hand flying the rest of the flight?

A

PITCH TRIM FAIL
PITCH MISTRIM
AILERON MISTRIM

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21
Q

What does PITCH TRIM ASYM mean for the AP?

A

AP will automatically disengage and cannot be re engaged

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22
Q

Can you re engage the AP or YD after a failure?

A

If they disengaged due to a fault they can be re engaged by pressing the reset button but if the cause of disengagement still exists, they will disengage again

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23
Q

What conditions prevent AP are-engagement

A
  • AP or YD failure
  • trim inoperative monitor failure
  • failure of AFCS control panel
  • if an app mode was selected at the time of the failure
  • if GA mode was selected at the time of the failure
  • if LOC or BC mode was selected at the time of the failure
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24
Q

What is TCS (Touch Steering Control)?

A

Pilot can manually change the aircraft’s attitude, altitude, vertical speed and airspeed without disengaging the AP

Press and hold TCS button on control column

25
Q

What happens to TCS if AP is in basic mode?

A

Pilot can reset the AP’s pitch and roll references and when TCS is released the AL will use the references that existed at the time the button was released

26
Q

What are the TCS pitch limitations?

A

Pitch angle must be within +/- 15 degrees when TCS is released

If pitch exceeds these values, the AP will automatically reset to +/- 15

27
Q

When are the flight director bars visible?

A

Only when an associated mode is selected

28
Q

What are the Flight Director vertical modes?

A

ALT SEL
ALT
VS
IAS

29
Q

What are the flight director lateral modes?

A

HDG
NAV
BC

30
Q

What are the flight director combined modes?

A

APP
GA

31
Q

What flight director modes are not selectable?

A

ALT SEL - automatically armed, both an AP and FD mode
GA - armed by pressing one of the GA buttons on the power leavers, a FD mode only

32
Q

What will the flight director command in GA mode?

A

The lateral bars will command the present heading

The vertical bars will command a safe pitch altitude based on flap setting and SE performance

33
Q

What mode stays active in GA mode?

A

ALT SEL - upon reaching a preset altitude it will be captured as normal

34
Q

Where are armed modes indicated?

A

On the third line of the ADU in white

35
Q

Where are captured modes indicated?

A

On the fourth line of the ADU in green

36
Q

What vertical modes have an armed status?

A

ALT
GS

37
Q

What lateral modes have an armed status?

A

VOR
LOC
BC

38
Q

How are captured modes displayed?

A

Displayed in green with an Asterisk
Contained within a box which lasts for five seconds

39
Q

Where will the AP ENG be displayed?

A

On the bottom right of the EADI in green

40
Q

What is the AP caution message on the EADI?

A

AP MSG in amber to tell crew to check ADU

41
Q

What is the AFCS normally coupled to?

A

Coupled to the captains side at initial power up and uses data from the associated ADC and SGU

42
Q

How can you change which side the AFCS is coupled to?

A

Press the CPL button on the AFCS control panel

The side it’s coupled to is indicated by a green arrow displayed on left side of the EADI, arrow will point in the direction of the coupling

The arrow next to the CPL pb will also indicate direction of coupling

43
Q

What modes will disengage after changing coupling?

A

NAV
BC
APP

44
Q

When does dual coupling occur?

A

Occurs automatically when the localiser and glideslope are captured provided both ILS receivers are turned to the same ILS frequency

Dual coupling will be indicated by illumination of both arrows either side of CPL pb

45
Q

What will the flight director be coupled to when approach mode is cancelled?

A

Flight director will remain coupled to the side selected at the time dual coupling occurred

46
Q

When will the GUIDANCE light illuminate?

A

In the event of excessive deviation during a dual approach or if CAT II engagement conditions are lost

47
Q

What happens if a sensor fails on the selected coupled side?

A

The AFCS can still be coupled but the FD mode that uses that failed sensor cannot be selected or engaged

48
Q

What does the STBY pb do on the AFCS control panel?

A

Cancels all armed and engaged flight director modes

If the AP is engaged it will revert to basic mode

49
Q

When is the altitude select mode automatically armed?

A

When the aircraft is climbing or descending towards a selected altitude

Altitude is set by rotating the ALT rotary switch

Selected altitude is displayed on the ADU

50
Q

What are the altitude select mode phases?

A

Armed phase - crew can use vertical speed hold, IAS hold or pitch hold to perform the climb or descent

Capture phase - mode used to fly the selected altitude is cancelled and AFCS will provide guidance to capture the selected altitude - indicated by ALT SEL CAPTURE on ADU and green ALT message on EADI

Altitude hold phase - once altitude has been captured. ALT message on ADU and green ALT message on the EADIs

51
Q

What is pitch hold mode?

A

Will automatically default to pitch hold mode if the selected altitude is changed during the capture phase

52
Q

What will happen when selecting the ALT pb?

A

The aircraft will round out the climb or descent to return and hold the altitude existing at the time the altitude hold mode was selected

53
Q

What happens when you press the VS mode?

A

Aircraft is placed in vertical speed hold mode

Action cancels any other active flight director vertical modes

54
Q

What will happen when the IAS pb is pressed?

A

The AFCS will provide guidance to maintain the indicated airspeed existing when the IAS pb was pressed

Airspeed will be displayed in green on the ADU

55
Q

What is over station mode?

A

When the aircraft is in the cone of confusion

AFCS will provide steering command based on heading only

56
Q

What will be displayed when the AFCS is tracking the localiser?

A

ADU and EADI will display a green LOC message

57
Q

How is the go around mode cancelled?

A
  • selecting another vertical mode
  • engaging the TCS
  • pushing the STBY pb
  • engaging the autopilot
58
Q

What is the altitude alerts?

A

Visual alert is an amber light on the two altimeters and an aural C chord tone

59
Q

When will the altitude alert light illuminate?

A

When the aircraft is within 1000 ft to 250 ft of the selected altitude