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B787 Flight Controls > Flight Controls > Flashcards

Flight Controls Flashcards

1
Q

What are the 3 primary flight control system modes?

A

Normal
Secondary
Direct

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2
Q

With the autopilot off, explain how control inputs are sent to the flight controls. (normal mode)

A

4 ACEs receive pilot control inputs and sends these signals to 3 PFCs. The PFCs verify these signals and information from other airplane systems to compute enhanced control surface commands. These commands are sent back to the ACEs, then to the flight control surface actuators.

AOM 9.20.6

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3
Q

Explain how the flight controls receive inputs with the autopilot engaged.

A

The autopilot system sends control surface commands directly to the 3 PFCs. The PFCs generate control surface commands which are sent to then ACEs and then to the flight control actuators.

AOM 9.20.6

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4
Q

Which flight control mode(s) allow for autopilot operation?

A

Normal mode only.
Autopilot is not available in secondary and direct modes.

AOM 9.20.9 and 9.20.10

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5
Q

In secondary and direct modes, what determines the elevator flight control feel force levels?

A

Flap position.
Normally the feel force changes with airspeed.

AOM 9.20.14

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6
Q

When do the PFCs automatically revert to secondary mode?

A

When inertial or air data is insufficient to support normal mode, or when ALL slat and flap position data is unavailable.

AOM 9.20.9

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7
Q

Do all flight controls remain operative in the secondary mode?

A

Yes.
However, the rudder and elevator become more sensitive at some air speeds and yaw damp is degraded.

AOM 9.20.9

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8
Q

What flight control functions are not available in the secondary mode?

A
  • Autopilot -pitch compensation
  • Auto speedbrake -roll/yaw asymmetry compensation
  • envelope protection -tail strike protection
  • gust suppression

AOM 9.20.9

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9
Q

Can the crew manually select the secondary flight control mode?

A

No.

AOM 9.20.9

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10
Q

When do the ACEs revert to the Direct control mode?

A

When the ACEs detect a failure of all 3 PFCs or lose communications with the PFCs.

AOM 9.20.10

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11
Q

Can the direct control mode be manually selected by the crew?

A

Yes. By moving the PRIMARY FLIGHT COMPUTERS disconnect switch to DISC

AOM 9.20.10

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12
Q

Which flight control functions are unavailable in the Direct mode?

A

The same as secondary.
Autopilot, pitch compensation, auto speedbrake, roll/yaw asymmetry compensation, envelope protection, tail strike protection, gust suppression.

AOM 9.20.10

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13
Q

How do the flight controls receive inputs in the DIRECT mode?

A

Pilot inputs are received by the ACEs and sent directly to the flight control actuators. The PFCs are not connected.

AOM 9.20.10

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14
Q

Up to what degree of bank do the PFCs provide pitch compensation?

A

30 Degrees of bank. Beyond 30, the pilot may need to increase pressure on the control column to maintain a level flight path.

AOM 9.20.11

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15
Q

INFLIGHT, after a pilot makes a primary pitch trim change, how do the PFCs physically trim the aircraft?

A

First the PFCs automatically move the elevator to achieve the trim change, then moves the stabilizer to streamline the elevator. (stabilizer motion can also occur automatically for thrust and configuration changes)

AOM 9.20.11

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16
Q

ON THE GROUND, how does the primary pitch trim function?

A

The stabilizer is directly positioned when using the pitch trim switches.

AOM 9.20.11

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17
Q

The pitch envelope protections include…?

A

Overspeed protection

Stall Protection

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18
Q

How does the overspeed protection help prevent an exceedance of Vmo/Mmo?

A

At Vmo/Mmo the trim reference speed is limited by inhibiting trim in the nose down direction. The pilot must apply continuous forward pressure at twice the normal force to maintain a speed above Vmo or Mmo

AOM 9.20.12

19
Q

How does the stall protection help prevent exceeding the stall angle of attack?

A

The trim reference speed is limited by inhibiting nose up trim when the airplane is at a speed where maneuver margin is limited (top of amber band at lower altitudes)

AOM 9.20.13

20
Q

Which control surface is locked out at high speed?

A

Ailerons

AOM 9.20.16

21
Q

How can the crew disable the bank angle roll protection?

A

The autopilot disengage bar on the MCP. (also maximum control wheel deflection will command maximum roll authority)

9.20.17

22
Q

What autopilot mode(s) is gust suppression available?

A

Altitude Hold or VNAV Level flight modes.

AOM 9.20.19

23
Q

The rudder trim is automatically zeroed during the takeoff roll when the aircraft exceeds ____ knots groundspeed.

A

30 knots

AOM 9.20.19

24
Q

How many spoilers are on each wing?

A
  1. 4 outboard and 3 inboard

9.20.21

25
Q

Which HYD systems provide power to the spoilers?

A

All 3 systems.

AOM 9.20.21

26
Q

How does the spoiler pairing prevent asymmetric roll conditions?

A

Each HYD system controls a pair of spoilers on opposite wings so if one HYD systems fails, then an equal number of spoilers fail on each wing.
(5 pairs are hydraulic… The remaining two pairs are powered by two electrical buses)

AOM 9.20.21

27
Q

When do the spoilers automatically deploy regardless of the handle position?

A
  • On the ground when airspeed is above 85kts, either thrust lever was in the takeoff range, and both are moved to idle(RTO)
  • When both thrust reversers are moved to the Idle detent.

AOM 9.20.22

28
Q

When do the spoilers automatically RETRACT?

A
  • On the ground when either thrust lever is moved to the takeoff range
  • During landing if the aircraft bounces and becomes airborne again
  • In the air when either thrust lever is moved beyond 90%

AOM 9.20.22

29
Q

When do the flight controls automatically unlock with the flight control lock switch in the LOCK position?

A

When groundspeed exceeds 40knots

AOM 9.20.4

30
Q

When do the slats move to the fully extended position?

A

When flaps 25 is selected.

AOM 9.20.24

31
Q

Which flap positions have flap load relief?

A

15 to 30

AOM 9.20.25

32
Q

What is slat autogap?

A

When the slats are in the middle position, the airspeed is less than 225knots and at high angles of attack, the slats automatically extend to full to increase the stall margin.

AOM 9.20.26

33
Q

At what speed and altitude are “cruise flaps” available?

A

Above 25,000
.54 to .87 Mach

AOM 9.20.27

34
Q

In the alternate flap/slat extension mode, how are the flaps/slats actuated?

A

Electrically

AOM 9.10.10

35
Q

In the alternate flap/slat extension mode, what is the maximum flap and slat position?

A

Flaps 20
Slats Midrange

AOM 9.10.10

36
Q

Flaps 15 placard speed? (787-8)

A

215kts

AOM 9.10.10

37
Q

Flaps 15 placard speed? (787-9)

A

220kts

AOM 9.10.10

38
Q

Flaps 1 Placard speed? (787-9)

A

260kts

AOM 9.10.10

39
Q

Flaps 5 Placard speed? (787-9)

A

240kts

AOM 9.10.10

40
Q

After landing, the flight control system conducts two tests automatically. The first is with HYD ON test. The test takes 90 seconds to complete after flap retraction. What would cause the test to stop automatically?

A
  • Taxi speed exceeds 35kts
  • Large input in the flight control system
  • HYD power is turned off

AOR 9.1.1

41
Q

How long does the HYD OFF flight control test take to complete?

A

70 seconds after HYD power is removed.

AOR 9.1.1

42
Q

When setting the stab trim for takeoff with a value near the edge of the green band, which direction should the stabilizer be moved?

A

Nose up to Nose down and do not pass the target stab setting. This reduces the chances of a takeoff config warning.

INFO #77

43
Q

What happens when there is a complete loss of flight control signaling? (all ACEs failed)

JCAB Oral Question

A

Direct wiring from the flight deck to the stabilizer and a spoiler pair allow pilot control of pitch using the alternate trim switches and roll using the control wheel

AOM 9.20.2

B787 Flight Controls (1 decks)

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