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HAC > AFCS > Flashcards

AFCS Flashcards

1
Q

What does SAS do?

What is the difference between SAS 1 and 2?

What percent control do they have?

A

Senses acceleration and applies control to reduce the rate.

SAS 1 is Analog, SAS 2 is Digital. They are identical except for the hover aug/ gust alleviation and alt hold/ hover coupler provided by SAS 2.

They have 10% authority With each providing 5%.

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2
Q

SAS 2 commands the collective inner-loop actuator by operating with ___________

A

RADALT, BARALT, APP/HVR and DEPART MODES ENGAGED.

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3
Q

Which SAS must be manually disengaged by the pilot if it has failed?

A

SAS 1

SAS 2 will be turned off by the AFCC.

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4
Q

Which trim servos are electric?

Hydraulic?

A

Yaw, collective

Pitch, roll

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5
Q

Trim is limited in movement by _________

A

10% percent per second

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6
Q

To disengage yaw trim above 50 kias the pilot must _________

Below 50 kias?

A

Push the cyclic button and the trim micro switches

Just the pedal micro switches

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7
Q

Auto pilot does what?

A

Maintains pitch and roll attitude, airspeed, heading during cruise

And

Provides a coordinated turn above 50 kias.

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8
Q

Attitude hold is engaged below _______, and using the 4-way trim switch will adjust pitch attitude at a rate of _________.

A

50 kias

5* per second

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9
Q

Airspeed hold is engaged ___________. The 4-way trim switch will adjust the airspeed by ___________. The lateral trim roll rate is _________. It resets to __________ when you ___________.

A

Above 50 KIAS and AOB less than 30*

6 KIAS per second

6* per second

Wings level

Accelerate through 50 kias

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10
Q

Heading hold is slewed at ____ below 50 kias and _______ above 50 kias.

A

3* per second

1* per click or 1* per second

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11
Q

Heading hold is re-engaged when what 2 conditions are met?

A

Roll attitude is within 2* of wings level

Yaw rate is less than 2* per second

Disengaged by WOW switch.

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12
Q

Altitude hold: The AFCC commands both the ____ and the ____ to maintain the reference altitude.

It will stop increasing power if torque hits _______ above 80 kias or ________ below 80 kias.

A

Collective SAS actuator and collective trim actuator

106%

120%

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13
Q

Altitude that RADALT will work?

A

0 to 5000ft AGL.

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14
Q

RADALT and BAR ALT require what push buttons to be engaged?

A

SAS 2, TRIM, and AUTOPILOT

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15
Q

RADALT climb and descent rates?

A

1000 ft per minute

200 ft per minute

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16
Q

What does hover augmentation/gust alleviation do?

A

Improves aircraft stability at low airspeeds by using attitude retention, longitudinal acceleration, and lateral acceleration to eliminate drift.

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17
Q

Turn coordination is provided ______. It will engage when _________ and any of what 3 conditions exist?

A

Above 50 KIAS

Roll attitude is greater than 1*

And either:

1) lateral cyclic displacement is greater than 3%
2) Cyclic TRIM REL is pressed
3) roll attitude is more than 2.5* using 4-way trim

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18
Q

The purpose of Maneuvering stability is to __________. It is provided by _________ between _______.

The ___________ push button must be engaged for it to function.

A

Increase pilot effort to maintain pitch rate at greater than 30* AOB

Pushing the cyclic forward by 1% for every 1.5* AOB. Between 30* and 75* AOB.

Autopilot

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19
Q

Automatic approach assumes _______ when engaged and again at ________.

A

Wings level

80 KIAS

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20
Q

The 4-way trim switch changes the deceleration rate by ________ during the automatic approach.

It will reset the deceleration profile at _____________. Pressing the ________ will reset the profile.

A

+- 1kt per second, 2 seconds for a full knot.

40KGS

TRIM REL

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21
Q

Automatic approach profile numbers?

ON (above 40KGS and below 40KGS)

Below-

Above-

A

Above 40: 2.5kt/sec 215 ft/min

Below 40: 1.5kt/sec 130 ft/min

Below profile: 2.5 kt/sec w/RADALT hold

Above profile: 360 ft/min w/airspeed hold

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22
Q

What is the Warning associated with an automatic approach?

A

If auto approach is turned on while in a trimmed turn it will spiral downward past the selected altitude and crash.

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23
Q

Hover coupler speeds can be varied by ________ with the 4-way trim switch.

Hover coupler will automatically engage after an automatic approach when __________ and manually when within ________

A

+- 10

Within 2 ft and 1KGS
Or
5KGS

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24
Q

The hover coupler will stop increasing the _______ at ________.

A

Collective torque

116%

25
Q

During couple hover if winds are greater than 50KIAS and the cyclic trim is depressed the ____________

A

Heading hold will be disabled. This could cause rapid deviation from the desired helicopter heading.

26
Q

Automatic depart, if not interrupted, will reach _____ and ______.

A

150ft and 120kias

27
Q

Automatic depart assumes __________ at _______ if bank angle is ________.

If bank angle is greater than ____.

Automatic departure will limit power at __________.

A

Wings level attitude, 50KIAS

Less than 5*

5* it will maintain a coordinated turn.

106 and 120% dependent on airspeed.

28
Q

Automatic departure profile?

A

240ft/min climb
3kt/sec below 85 kts

1kt/sec above 100 kts

29
Q

Crew hover control authority?

A

+- 5 KGS

30
Q

Cable angle is decoupled from the AFCS for ____ when dome raising/lowering is stopped or started in the water.

A

9 seconds

31
Q

Scale on the cable angle display is _________. The rings are at _____ and ______.

A

2 degrees per tick

  1. 25 degrees
  2. 5 degrees
32
Q

CABLE ANGLE AT LIMIT caution appears when ___.

A

cable angle has exceeded 7.5 degrees total deflection.

33
Q

The helicopter will default to HVR mode at _________ during cable angle hover.

If either axis is failed it must be _________.

What should you not continue if both axis are failed?

A

27+- 12 ft water depth.

Manually controlled

Dipping operations.

34
Q

What is required for Cable Angle Hover Mode?

A

KGS of +-5

Altitude hold w/in 10 ft.

Dome wet indication.

35
Q

The ______ are inoperative when CABLE ANGLE HOVER is engaged.

A

LONG VEL and LAT VEL potentiometers.

36
Q

Cable angle takes ______ to come up with a solution.

A

25 seconds. Do not make inputs during this time.

37
Q

Cable angle hover will not _________ with ____________ engaged.

A

Disengage

Cable angle override on. (Must be manually disengaged)

38
Q

To conduct AFCS preflight checks you need:

BREWS

A 
Both EGIs attitudes valid
Rotor brake ON
Engine torque below 10%
WOW
SAS 1 ON (AFCC must be on for at least 20seconds)
39
Q

If one of the SAS channels fail, what operable control authority is the operable channel limited to?

A

+-5 percent authority, but it operates at twice the normal gain to compensate for the failed SAS channel

40
Q

When does the SAS caution appear?

A

Whenever SAS 1 and SAS 2 lose electrical power or when hyd pressure is lost to the actuators.

41
Q

Is Trim an outer-loop functions, or inner-loop?

A

Outer-loop

42
Q

Cable angle is used to keep the cable ____ to the water.

A

Perpendicular

43
Q

What does the SUBM OVRD button do?

A

Provides override capability of the 27+-12 ft submerge requirement to engage cable angle hover mode. (in case you’re dipping in shallow water or don’t have the dome wet indication.)

44
Q

How do you initiate the automatic preflight check?

A

by pressing the SAS 1 pushbutton. Takes approx 10 seconds to complete.

45
Q

3 major subsystems

A

SAS
AFCC
Stab

46
Q

19 Functions of the AFCS

A

6 hover, 5 hold, MASTBSTD

  1. Maneuvering stability
  2. Automatic preflight checks
  3. Stability augmentations (pitch, roll, yaw)
  4. Turn coordination
  5. Blade Fold Assist
  6. Stab Control
  7. Trim (pitch, roll, yaw)
  8. Diagnostics
  9. Crew hover
  10. Cable angle hover
  11. Auto approach
  12. Auto depart
  13. Hover coupler
  14. Hover augmentation/gust alleviation (pitch and roll)
  15. BAR Alt
  16. RAD Alt
  17. Heading hold
  18. Attitude hold (pitch and roll)
  19. Airspeed hold
47
Q

2 types of AFCC control

A
  1. Inner loop (SAS)

2. Outer loop (autopilot)

48
Q

Inner loop is

A

fast in response, limited in authority, and does not move the flight controls

49
Q

Outer loop provides

A

Long term input by moving flight controls through their full range of travel (100% authority) at a limited rate of 10% a second

50
Q

ATT caution cube indicates loss of pitch or roll attitude or

A

3 deg miscompare between EGIs

51
Q

AFCC uses the ___ to choose between the ___ for the best source of power

A

Voltage sensor relay

AC primary buses

52
Q

4 Inputs to the Stab

A

Collective Position
Lateral Acceleartion
Airspeed
Pitch Rate

53
Q

How is the stab positioned? What buses power its movement?

A

2 electrical jackscrews acting in series
Each jackscrew provides 1/2 the input
DC Essential & No 1 DC Primary

54
Q

Stab movement if it fails full down/up?

A

35 degrees if fails full down, 30 if full up

55
Q

Primary purpose of the stabilator

A

To eliminate undesirable nose up attitudes caused by rotor downwash on the horizontal stab during transition to a hover and low speed flight

56
Q

When is the TEST pushbutton for the stab operable?

A

Below 50 KIAS

57
Q

Range of motion for the stab

A

42* trailing edge down for hover/low speed flight (below 30 KIAS) to 10* trailing edge up for cruise and maneuvering flight

58
Q

AFCS is what type of system?

A

Electrohydromechanical

HAC (47 decks)

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