FIGHT CONTROLS Flashcards
(124 cards)
1
Q
How many operating modes are there for the primary flight controls?
A
3
Normal mode
Secondary mode
Direct mode
2
Q
Describe the FLT CTRL operating schematic?
A
Control sends an analog signal to the ACE
ACE(Actuator Control Electronics) converts this to a digital signal and sends it to the PFC(Primary Flight Computers)
The PFCs send a signal back to the ACE which converts them back into analog and sends them to the PCU(Power Control Unit)
PCUs gives the power to operate the flight controls
3
Q
What are the inputs to the PFCs?
A
Airspeed
Air data
Inertial data
Flap/slat position
4
Q
How are the primary flight controls operated?
A
Electrically operated but hydraulically actuated
5
Q
What unit drives the flight controls?
A
PCU drives the pirmary flight controls
6
Q
Which controls have jam override mechanisms?
A
Control columns and wheels
7
Q
Which controls are ridgidly connected to each other?
A
The rudder pedals
8
Q
How many ACEs and PFCs are there in the flight control system?
A
4 ACEs
3 PFCs
9
Q
Why do the PFCs receive other data inputs?
A
To compute control surface commands for improved handling characteristics
10
Q
How does autopilot commands get routed to control surfaces to create movement in comparison to manual control inputs?
A
Sends commands directly to the PFCs and not via the ACE
11
Q
Which control surfaces provides Roll control?
A
14 spoilers
2 ailerons
2 Flaperons
12
Q
Which control surfaces provides Pitch control?
A
Elevators
THS
13
Q
Which fight controls provides yaw control?
A
Dual surface hinged rudder
14
Q
When do the aileron droop, and why?
A
With flaps 5, 15 and 20 selections to improve take-off performance
15
Q
When and how does the flaperons droop?
A
Move down and aft in proportion to trailing edge flap extension
16
Q
What are the flaperons used for?
A
In normal mode for roll control but also for increased lift
17
Q
What are the 3 protection features for the flight controls?
A
1 Stall protection
2 Overspeed protection
3. Bank angle protection
18
Q
What functions work in Normal Flight Control Mode?
A
Auto spd brake
Auto pilots
All 3 protections
PFCs and ACEs
19
Q
When does the system switch to Secondary Flight Control mode?
A
If airspeed and/or inertial data is lost
20
Q
What functions are lost in Secondary Flight Control mode?
A
All 3 protections
Auto spd brake
Auto pilot
Yaw damping is lost or degraded
21
Q
Are the PFCs and ACEs working in secondary mode?
A
Yes and full manual control is retained
22
Q
When is Direct Flight Control Mode operative?
A
Goes to this mode if other failures occur or if the pilot selects DISC for the “Primary Flight Computers” switch.
23
Q
Are the ACEs and PFCs working in Direct mode?
A
ACEs are working. Sends signals direct to the PCU and skips the use of the PFCs
24
Q
Which HYD systems powers the elevator?
A
Left, Center and Right
25
Describe stall warning system?
There is a stick shaker but no aural warning.
Top of amber band is the manouvering speed and is the lowest speed the aircraft can be trimmed to. In the amber band a caution "AIRSPEED LOW" comes up on EICAS
If A/T is armed it will automatically engage in the amber band
If A/T is off but A/P is on, the aircraft will pitch forward to increase speed
26
Which HYD systems powers the THS?
Center and Right HYD systems
27
What are the inputs to the stabilizer green band indicator?
CG
T/O thrust
Gross weight
28
How is the calculated stabilizer green band double checked for accuracy?
By a nose gear oleo pressure switch that double checks the CG
29
What does the EICAS message "STAB GREEN BAND" mean and what could be the problem?
The nose gear x-check function disagrees with greenband calculation
Problem can be incorrect entry into FMC
30
Does the control wheel pitch trim work when the autopilot is engaged?
No, it is inhibited
31
With no autopilot engaged, when is pitch trim necessary?
Only when airspeed is changed
32
Describe how pitch trim is achieved in flight with autopilot engaged?
1. Set speed on MCP, that sends info to the PFCs to change trim reference speed
2. PFCs send signal to ACEs to position the elevators via the PCU
3. Elevator moves to the required position
4. Stabilizer streamline with the elevator
33
How much does the trim reference speed change when the trim switch is operated?
Approximately 10 kts/second
34
On the ground, what are the trim switches on the control wheel used for?
Directly positioning the stabilizer
35
What surface do the primary pitch trim switches move in flight?
The elevators via the PFCs-ACEs and the PCU
36
Which surfaces have cable driven back-up?
Stabilizer and spoilers 4 and 11
37
When will trim in the nose up direction be inhibited?
When close to the manouvre margin speed
38
When will overspeed protection occur?
At Vmo or Mmo
39
How many levels on elevator feel exists in Secondary and Direct mode?
2. Control column force is lower with flaps extended
40
Which spoiler surfaces are mechanically controlled?
4 and 11
41
What does the Alt pitch trim lever do?
Moves cables that controls the THS dirctly in all modes. Levers are spring loaded to neutral
42
Can the Alternate Pitch trim be used when autopilot is engaged?
Yes
43
Describe tail strike protection?
The PFCs calculates the rotation rate and decreases elevator deflection if needed
44
When do control column forces increase?
When airspeed increases, in Normal mode
45
How are control column commands changed in secondary and direct mode?
Control column now commands a proportional elevator deflection instead of a manoeuvre command
46
What happens is one control column jams?
Applying force on the other control wheel overrides the jam
47
What is an STCM?
Stabilizer Control Module
48
What does the stabilizer cut out switches control?
Controls HYD power to the respective STCM. Placing both switches in cut out removes HYD power from the stabilizer
49
Is stab trim possible with one cut out switch in "cut-off"?
Yes, through the other STCM and other HYD system.
50
Which control surfaces are normally locked out in cruise?
Ailerons and
Spoilers nr 5 and 10
51
Which flight control modes allow for autopilot operation?
Only the Normal Mode
52
Can the plane be controlled with a complete electrical shutdown?
Yes, via cables to the stabilizer and spoilers 4 and 11 as long as there is some HYD power
53
Can the autopilot be overridden by pilot control inputs?
Yes
54
When are the ailerons used?
At low speed only
55
Is aileron trim available with the autopilot engaged?
No, it is inhibited
56
What is the bank angle protection boundry, and what happens if it is exceeded?
35 degrees
Control wheel force rolls the plane back to within 30 deg bank
This roll command can be overridden by the pilot to enable steep turns
57
Does the control wheel move when aileron trim is used?
Yes
58
What happens to roll control in Secondary and Direct modes?
Roll control is very similar
Bank angle protection is not available and spoilers 5 and 10 are locked out
59
Which spoilers are not available for roll control at high speed?
Nr 5 and 10
Only available at low speed
60
Which HYD system gives power to the ailerons?
Left and Center system together for each aileron
61
Which components gives yaw control?
1 Rudder pedals
2 Rudder trim
3 Rudder ratio system
4 Yaw dampers
62
Which component reduces rudder authority at higher speeds?
Rudder ratio system
63
What device provides additional yaw authority?
A tab that deflects twice as far as the main rudder surfaces to provide additional yaw authority
64
In normal mode, what functions are provided by the yaw damping system?
Turn co-ordination and
Dutch roll damping
65
Are the rudder pedal forces affected by airspeed?
No, pedal forces increase as pedal displacement increases
66
How does the rudder ratio system work?
At low speed the rudder has full deflection with full pedal displacement
At high speed the rudder has smaller deflection with full pedal displacement
67
Is the rudder ratio system operative in Secondary and Direct mode?
No, changes to two fixed modes
With flaps UP, the rudder displacement is less than for flaps DOWN
68
Is there a separate yaw damping system on the B777?
No, PFCs sends commands via the ACEs to the PCU to control Dutch roll and turn co-ordination
69
Which HYD systems powers the rudder?
All 3 HYD systems separately via a PCU
70
What does the MANUAL TRIM CANCEL pushbutton do?
Cancels manual trim that the pilot put in. Keeps trim that the aircraft itself put in
71
What is the rudder trim position for T/O?
It should be zero
72
What is gust suppression?
It reduces the effects of lateral gusts and improves lateral ride stability through a combination of yaw and roll commands
73
How is gust suppression achieved?
Transducers sends a signal to the ACEs, then to the PFCs, then back to ACEs and then to the PCU to dampen the force
74
Does the gust suppression move the rudder pedals?
No
75
What is TAC?
Thrust Asymmetry Compensation
It assists the pilot to maintain directional control after an engine failiure
Also assists the pilot when thrust levers are split
76
When does TAC start to work?
When there's a 10% difference in thrust level between the engines
Is armed over 70 kts
77
Does the rudder pedals move when TAC is active?
Yes
78
In what modes are TAC and Gust Suppression available?
In Normal Mode only
79
When does TAC not work?
Below 70 kts and
When reverse is applied
80
When can control wheel input cause rudder deflection and how much rudder deflection can you get?
During engine failiure, the "Wheel to rudder cross tie" system delects the rudder up to 8 degrees
81
In what mode is Wheel to rudder cross tie available?
In Normal Mode only
82
Under what condition does the Wheel to rudder cross tie system work?
Below 210 kts in Normal Flight Control mode
83
How does the turn compensation system work, and in which modes does it work?
No back pressure is needed for turns between 0-30 deg
Partial compensation from 30-60 deg
Only works in Normal Mode
84
Normally, do all spoilers operate as speed brakes on the ground?
Yes
85
Which spoilers are normally locked out in flight as speed brakes?
Nr 5 and 10
86
Which spoilers are locked out as speed brakes in Secondary and Direct modes?
Nr 4, 5, 10, 11
87
If armed, when do the speed brakes extend?
When the landing gear is fully on the ground, not tilted and the thrust levers are at idle
88
Does the speed brake lever move automatically for extension?
Yes, from ARMED to UP
89
What are the speed brake lever positions?
Down, armed and up
90
Describe the 3 automatic features of the speed brake system
1. Moves the lever to down for T/O
2. During an RTO when reverse is engaged the speedbrakes automatically comes up and lever moves to up
3. For landing with speed brakes armed the speed brakes automatically moves to up.
Speed brakes are also automatically operated for landing when reverse is engaged
91
In wich modes does the auto speed brake function operate?
Only in Normal Mode
92
What 3 mode of operation does the high lift devices have?
1. Primary (Hydraulic)
2. Secondary (Electrical)
3. Alternate (Electrical)
93
What hydraulic system operates the Flaps/slats in primary mode?
The C HYD system
94
When a flap lever is moved, where is the signal sent to?
To two FSEU (Flap Slat Electronics Units)
95
In what modes does the FSEU work?
In primary and secondary mode
96
What is the purpose of the Krueger flap?
To provide a seal between the inboard slat and the engine nacelle
97
What flap positions are available?
1, 5, 15, 20, 25 and 30
98
What are the flap limit speeds?
1 = 265
5= 245
15=230
20=225
25=200
30=180
99
When is flap/slat operation inhibited?
With speed over 275 kts and above approximately 20'000 ft
100
How any slats are there?
7
6 outboard and 1 inboard
101
When are the Krueger flaps extended?
At selection of Flaps 1 together with the slats
102
What high lift surfaces are moved with selection of Flaps 1?
The slats to their mid position and the Krueger flaps
103
What high lift surfaces move with selection of Flaps 5, 15, 20, 25 and 30?
5= Flaps only
15= Flaps only
20= Flaps only
25= Slats to full and Flaps
30= Flaps only
104
What are the normal landing Flap positions?
Flap 25 and 30
105
How does the flap load relief system work, and in what control mode are they available?
Only available in Primary mode
It protects the flaps from excessive air loads. Works from Flap 15 to 30(takes it back to 5 for 15)
Flaps retract when speed is 1 kt over the limit speed. When speed is 5 kts below the limit speed the re-extend.
106
In what modes are Flap relief available?
Only in the Primary mode
107
In what modes are Slat relief available, and how does it operate?
Available in Primary and Secondary mode
If speed exceeds 256 kts with slats fully extended they retract back to mid range and EICAS message "LOAD RELIEF" is displayed
108
When does Secondary high lift device mode become active?
Engages automatically when the primary (HYD) fails to move flaps/slats
109
How are flaps powered in Secondary high lift device mode?
Electrically and at a much slower speed
110
How is the Flap indications changed in Secondary mode?
An expanded view comes up
111
When is alternate high lift device mode engaged, and how does it work?
When both Primary and Secondary fails
Must be manually selected. When selected it overrides the Flap lever
The extend/retract signal bypasses the FSEUs and is sent directly to the flap/slat electric motor
112
What are the flaps/slats positions available in alternate high lift device mode?
Flap 1, 5, 20
Slats goes to midrange
113
How is the slats moved during alternate high lift device mode?
Slats extend together with the Flaps but slat retraction is inhibited until the flaps are up
114
What protective functions are not available in Secondary and Alternate high lift device mode?
Secondary: No load relief
Alternate: No load relief, Asymmetry and auto slats
115
Why are the slats fully extended in Secondary mode?
Because no Auto-slat is available they go to fully extended at all flap positions to improve stall handling characteristics (if airspeed is below 256 kts)
116
What is the purpose of the auto-slat function, and how does it work?
Purpose is to improve stall characteristics
Auto-slat is armed at Flaps 1, 5, 15 and 20 and is available only in primary mode.
Slats extend from mid range to fully extended if a signal from the stall warning system is received
117
How is the stall protections system operating?
Trim inhibit speed is approximately top of amber band(MMS) at lower altitudes but can be 10 to 20 knots lower at higher altitudes. Near stick shaker activation the autothrottles automatically activates and maintains MMS or the speed set in the MCP speed window, whichever is greater. EICAS “AIRSPEED LOW” will show in amber band.
118
How many computer processors are there in each PFC?
3, so there are 9 in total as there are three PFCs
119
What is the EICAS message to indicate that Secondary Flight Control Mode is active?
EICAS message “FLIGHT CONTROL MODE” will appear when Secondary mode is active
120
What is the EICAS message to indicate that Direct Flight Control Mode is active?
EICAS message “PRI FLIGHT COMPUTERS” will appear when Direct mode is active
121
What is the TAC actually controlling in order to correct for thrust assymetry?
TAC typically does not provide a rudder input. In fact, the TAC drives the rudder trim control that in turn drives the rudder pedals on the bottom of the pilot’s feet, which drives the rudder.
122
Why can't the TAC control 100% of the rudder input needed during an engine failure? What is the purpose of it not controlling it 100%?
During an engine failure during take-off you can’t only control the yaw with rudder trim and so the TAC can’t do this either. Therefore you have to use rudder inputs yourself to keep the aircraft moving straight.
123
Why can the TAC fail at a critical engine failure situation?
During catastrophic engine failures, there are short periods of time when the engine parameters feeding into the on board computers are invalid. When this is sensed by the TAC – it fails. Since TAC feeds in rudder pressure based on calculated thrust difference – if it can’t calculate thrust on an engine – it can’t safely feed in rudder.
124
In what modes are turn compensation to hold level flight available?
Only in Normal Mode
