9 - Flight Controls Flashcards

1
Q

What are the three Primary Flight Control operating modes?

A

-Normal

-Secondary (can not be manually
selected)
-Direct (handling qualities approx
same as Secondary mode)

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2
Q

Control inputs are sent to ____ , those signals are sent to ____ which send the signals ____ which send enhanced signals to the flight controls.

A

4 ACEs (Actuator Control Electronics)
3 PFCs (Primary Flight Computers)
back to the 4 ACEs

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3
Q

Which pilot controls have jam override
mechanisms and which are rigidly connected?

A

Columns and wheels - override

Rudder pedals - rigidly connected

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4
Q

PFCs use information from other airplane systems such as: (5) to compute enhanced signals

A

Air data
Inertial data
Flap and slat position
Engine thrust
Radio altitude

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5
Q

Roll control provided by?

A

2 - Ailerons (move down for flaps
5, 15, and 20 to improve TO
performance)
2 - Flaperons (with flap retracted or
extended)
14 - Spoilers

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6
Q

Yaw control provided by?

A
  • Single rudder (almost same height as tail)
  • Partial span tab (lower portion that deflects twice as far as the rudder)
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7
Q

In normal mode what locks out during high-speed flight?

A

Ailerons
Spoilers 5 and 10

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8
Q

What flight control system mode(s) provides envelop protection and what are they? (3)

A

Normal Mode only

Stall protection
Overspeed protection
Bank angle protection

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9
Q

What is the difference between
Normal and Secondary mode and how is the pilot notified he is in Secondary mode?

A

PFCs use simplified computations to generate flight control commands

FLIGHT CONTROL MODE

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10
Q

What is not available in Secondary mode? (6)

A

Autopilot
Auto speedbrakes
Envelope protection
Gust suppression
TAC (Thrust Asymmety Compensation)
Yaw damping (degraded or inop)

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11
Q

What causes the Flight Control System to switch to Direct mode and what is the indication?

A

Auto - failure of all three PFCs, or ACEs
lose communication with PFCs
Manual - PFC switch to DISC

PRI FLIGHT COMPUTERS

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12
Q

What functions are not available in the Direct mode? (7)

A

Autopilot
Auto speedbrakes
Envelope protection
Gust protection
TAC (Thrust Asymmetry
Compensation)
Yaw damping
Rudder trim cancel switch

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13
Q

Is there a mechanical backup system in the event of a complete electrical failure for the flight controls? How does it work?

A

Yes

Cables from the flight deck to the stabilizer and spoilers 4/11 permit straight and level until the electrical system can be restarted

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14
Q

How do PFCs control pitch?

During landing?

A

PFCs automatically position elevator and stabilizer to generate the commanded maneuver

Command a slight nose down pitch so pilot has to flare

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15
Q

How does pitch trim differ between in the ground and in flight?

A

On the ground - stab moves

In flight - inputs to PFCs change the trim reference speed. PFCs move the elevator, then move the stab to streamline (stab auto streamlines for thrust and configuration changes )

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16
Q

How does ALT Pitch Trim work?

A

ALT trim levers linked to the STCMs (Stabilizer Trim Control Modules) by cables and then mechanically to stab. ALT pitch trim commands have priority over wheel switches in all flight control modes and does not disconnect the autopilot.

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17
Q

How does Stall Protection/Overspeed Protection work?

A

Limits the speed to which the airplane can be trimmed (minimum maneuvering speed (top of the amber band) - VMO/MMO

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18
Q

Describe Tail Strike Protection

A

PFCs calculate if a tail strike is imminent and decreased elevator deflection (no control feedback)

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19
Q

How does pitch control differ in Secondary or Direct mode from Normal mode?

A

Moves elevator, there is no trim reference speed. Pitch trim switches move stab. Spoilers 5/10 locked out.

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20
Q

What is the power source for the stab trim?

A

C and R hydraulic systems (normal and alternate both use the same stab trim control modules, one for each hydraulic source)

21
Q

What does STABILIZER C or R indicate?

A

Uncommanded stab motion sensed (automatic shut off) or another failure.

22
Q

What does STABILIZER indicate?

A

Both stab trim control modules automatically shutdown or fail or automatic shutdown fails to stop uncommanded motion

23
Q

Is pitch trim available with both Stab Cutout Switches in CUTOUT?

A

Yes, in Normal Mode. Pitch trim inputs change the PFC trim reference speed which repositions the elevator

24
Q

How is the Stab Trim Greenband calculated? How is it cross-checked?

A

FMC entered GW, CG and TO thrust

Nose gear oleo strut (STAB GREENBAND if press switch and Green Band disagree)

25
Q

What happenes to flight controls at high speed?

A

Ailerons and spoilers 5/10 are locked out

26
Q

What is ‘maneuver load alleviation’ and when does it operate?

A

Moves spoilers and ailerons to reduce wing loads caused by pilot inputs in Normal Mode with flaps up

27
Q

What is Bank Angle Protection?

A

If the boundary is exceeded, (approximately 35 deg), PFD bank indicator turns amber and the control wheel rolls bank back to 30 deg. Can be overridden by the pilot.

28
Q

What does the Rudder Ratio Changer do?

A

Automatically reduces rudder deflection (for a given pedal input) as airspeed increases

29
Q

What is the TAC and what does it do?

A

Thrust Asymmetry Compensation automatically adds rudder to minimize yaw if one engine thrust differs more than 10%. (Partial during TO, full after liftoff)

30
Q

When is the TAC available/not available (3)?

A
  • only available in Normal Mode

Not available;
- below 70 kts
- reverse thrust
- system malfunction or loss of engine
thrust data

31
Q

What is Wheel to Rudder Cross-Tie?

A

Controls the initial effects of an engine failure inflight, (Normal Mode, below 210 kts), using control wheel inputs only. Control wheel inputs can deflect the rudder up to 8 deg.

32
Q

What is Gust Suppression?

A

Reduces the effect of lateral gusts through a combination of yaw and roll commands without rudder pedal or control wheel movement.

33
Q

How is yaw control different in Secondary and Direct Modes?

A
  • TAC inop
  • gust suppression inop
  • yaw damper degraded or inop
    (rudder ratio has two fixed ratios
    determined by flap position)
  • manual rudder trim cancel switch
    inop (Direct Mode only)
34
Q

How many spoiler panels are there and when do they operate in flight?

A

14; 5 outboard and 2 inboard of the Flaperons on each wing. (If a single spoiler fails symmetrical spoiler on other wing retracts)

Spoilers 5/10 are locked out during cruise, (depending on speed/altitude)

35
Q

How do Speedbrakes work? Is there any limitation speed/configuration?

A

Used to supplement roll control and increase drag and reduce lift. 5/10 are locked out during cruise, (depending on speed/altitude). 5/10 available as ground spoilers only, 4,5/10,11 locked out in secondary and direct modes.

No limitation (can be used in Lndg Config)

36
Q

How do ground spoilers work? And when does Auto operate?

A

Only in NORMAL mode

Armed - speedbrake lever driven up when Lndg Gr not tilted and thrust levers at idle

Disarmed - either thrust lever moved to reverse

Down - either T/L advanced to TO

37
Q

What is LAM and when does it operate?

A

Landing Attitude Modifier - automatic function used to increase pitch attitude when landing flaps are selected at higher speeds by partially selected lateral control surfaces. (Decreased lift requires increase pitch. Some airframe buffet may occur).

38
Q

How many Flaps and Slats and what is there power source?

A

4 Flaps / 14 Slats, 2 Krueger Flaps
(provides a seal between the inboard slat and engine nacelle)

Primary - C Hyd

Secondary/Alternate L and R AC Busses

39
Q

Flap/Slat sequencing - Normal Mode

A

F1 - Slats move to midrange
F5 - Slats remain in midrange
F25 - Slats extend full, then flaps

(retraction - sequencing is reversed)

40
Q

Flap/Slat sequencing - Secondary

A

Secondary- Slats fully extend at all flap positions when less than 256 kts. If A/S above 256 kts slats retract to mid. Autoslats not available.

(If slats in midrange when Secondary Mode engaged, they remain in mid until Lndg Flaps or flaps up)

41
Q

Flaps sequencing - Alternate (ARM)

A

Limited to F20 and slats mid

Extend/retracts flaps/slats simultaneously, (slat retraction inhibited until flaps are up)

ARM Switch - Inop
- flap lever
- asymmetry protection
- uncommanded motion protection
- autoslats
- flap/slat load relief

42
Q

When is Flap/Slat load relief available and how does it work?

A

F15-30 (Primary Mode only) - 1 kt above placard speed LOAD RELIEF, flaps retract until 5 kts below placard speed then re-extend.

Slats (Primary/Secondary) - exceeds 256 kts with slats fully extended - LOAD RELIEF, slats retract to mid

43
Q

What are Autoslats and when do they operate?

A

Stall warning signal fully extend slats from midrange only in Primary Mode. Retracts to mid a few seconds after signal is removed.

44
Q

What happens if uncommanded flap or slat motion is detected?

A

Causes auto transfer to Secondary Mode, FLAPS or SLATS PRIMARY FAIL displayed. If motion continues, the system shuts down and FLAPS or SLATS DRIVE msg is displayed.

45
Q

When is flap/slat extension inhibited?

A

Speed more than 275 kts or altitude above 20,000 ft

46
Q

What happens about 2 min after HYD PRESS SYS L+C+R is displayed after shutdown?

A

PFC self test - various EICAS msgs, trim indicator blinks and failure indications on FCTL synoptic

47
Q

How does the elevator variable feel system differ in Secondary and Direct mode?

A

Provides two feel levels instead of a continuous variation with airspeed, (flaps up/flaps down)

48
Q

What are the three Flap and Slat modes?

A
  • Primary (C Hyd)
  • Secondary (L/R AC Bus)
  • Alternate (L/R AC Bus)