A320 Landing Gear & Brakes Flashcards
(109 cards)
1
Q
What controls the landing gear?
A
It’s controlled by the 2 Landing Gear Control Interface Units (LGCIU’s)
2
Q
What controls the nose wheel steering and brakes?
A
Brake Steering Control Unit (BSCU)
3
Q
On the wheels page, when do you get a green arc over one of the brakes?
A
It appears over the hottest brake between 100ºC-300ºC
4
Q
How can you see the brake accumulator pressure?
A
Triple Pressure indicator next to the gear lever. It’s powered by the yellow hydraulic system.
5
Q
How is the nose gear controlled?
A
It’s electrically controlled and hydraulically operated by the green hydraulic system
6
Q
What hydraulic system actuates all gear and doors?
A
The green hydraulic system
7
Q
Above what speed does the safety valve automatically cut off hydraulic supply to the landing gear system?
A
260kts. Remember that Vle (extension) is 250kts. Cutting off pressure at 260kts ensures you won’t accidentally exceed the landing gear extension limit by more than 10 knots.
8
Q
Can the gear be retracted with a green hydraulic system failed?
A
No
9
Q
How can the gear by extended when the green system is failed?
A
Turn the emergency extension knob 3 times
10
Q
What does the red light on the outside nose gear indicate?
A
That the parking brake is set
11
Q
What hydraulic system controls nose wheel steering?
A
Yellow for nearly all of our aircraft. There’s a few who use the green system (203, 204, 218, 219) - edit - It appears that none of the green system aircraft are still in service.
12
Q
What auto brake setting do we use for takeoff?
A
MAX.
13
Q
What are the 4 braking modes?
A
Normal
Alternate with anti-skid
Alternate without anti-skid
Parking brake
14
Q
What auto brake modes are used for landing?
A
MED or LO
15
Q
What do the proximity sensors do?
A
They monitor the gear uplock, downlock, and shock absorber positions, as well as gear door positions and send information to the LGCIU’s.
16
Q
Which LGCIU operates as a backup?
A
It alternates each time the landing gear is retracted.
17
Q
What prevents gear up on the ground?
A
The interlock, which is activated if any of the gear shock absorbers are sensed as compressed.
18
Q
Can the crew override the interlock?
A
No
19
Q
What do the landing gear lights indicate when the gear is up?
A
Lights out
20
Q
When does UNLK appear on the landing gear lights?
A
When the gear position differs from the position selected by the landing gear selector
21
Q
What to the green triangles represent on the landing gear lights?
A
Down and locked
22
Q
Which LGCIU provides information to the landing gear indicating panel?
A
LGCIU 1. If this is failed you’ll need to refer to the WHEEL page for gear position.
23
Q
Apart from the landing gear, what else do the LGCIU’s do?
A
They also determine the air/ground status of the aircraft, and supply landing gear information to the ECAM display. Additionally the monitor the locked position of the cargo doors.
24
Q
How many doors are on the nosewheel gear?
A
5, 2 forward doors, 2 aft doors, and 1 rear door
25
Which doors remain open when the nose gear is in extended position?
The 2 aft doors, and the single rear door. The 2 forward doors are closed when the nose gear is extended, but the do open temporarily during the actual extension and retraction of the nose gear.
26
How are the main gear doors operated?
They are electrically controlled, and hydraulically operated by the green hydraulic system
27
What do the proximity sensors do?
They monitor the landing gear uplock, downlock, shock absorber positions, and gear door positions. They send this information to the LGCIU’s.
28
What sends information to the LDG GEAR indicator panel?
LGCIU 1 only
29
What happens if one LGCIU fails?
The other one automatically takes over
30
What monitors the position of the landing gear lever?
The LGCIU’s
31
What electronically sequences the gear extension and retraction?
The LGCIU’s
32
What prevents the landing gear lever from being placed in the UP position on the ground?
The interlock
33
What activates the interlock?
If a main gear or nose gear shock absorber is sensed compressed by the proximity sensors, the interlock is activated.
34
Above what speed does the safety valve prevent movement of the landing gear?
260kts
35
What is the condition of the LDG GEAR indicator panel when the gear is UP?
Lights out
36
When do the UNLK lights illuminate on the LDG GEAR indicator panel?
When the gear position differs from the position selected by the landing gear lever
37
What is shown on the LDG GEAR indicator panel when the gear is down and locked?
The green down triangles
38
What will be displayed on the LDG GEAR indicator panel when LGCIU 1 is inoperative?
Nothing. Since only LGCIU 1 sends info to the LDG GEAR indicator panel, when it’s inoperative the indicators should be blank. In this circumstances the WHEEL page should be used for gear position info.
39
What should be used for gear position info if LGCIU 1 is inoperative?
The WHEEL page. In this circumstance the LDG GEAR indicator panel will remain blank.
40
When is the WHEEL page automatically displayed?
-On the ground after the engine start sequence is complete
-In flight when the landing gear lever is moved to the DOWN position
41
What indication should you get on the WHEEL page to let you know that the gear is down and locked? To let you know that the doors are closed?
2 green downward triangles for each of the 3 gears. The gear door bars are in the horizontal position.
Note: if one gear indicator on the wheels page is red (indicating it’s in transit or at least not locked down) and the same tire on that gear is green, that is a sufficient indication that the gear is locked. See Vol 3, currently page 2460.
42
What does a red downward triangle on the WHEEL page represent?
That the LGCIU senses that the gear is not down and locked
Note: If there’s a red downward triangle on the wheels page, indicating that it’s not locked, but its partner wheel is displaying a green downward triangle, that is sufficient to indicate that the gear is in fact down and locked. See Vol 3, currently page 2460.
43
What’s the maximum speed at which the gear may be extended?
250kts
44
What’s the maximum altitude at which you may extend the gear?
FL250
45
What’s the maximum speed with the gear extended?
VLE = 280kts/0.67M
46
What’s the maximum speed to retract the gear (VLO (RET))?
220kts
47
When does the LDG memo appear on the E/WD?
Below 2000’ AGL and in the approach phase
48
When do you get the L/G GEAR NOT DOWNLOCKED ecam?
When a malfunction is sensed that is preventing the gear from locking down
49
When do you get the L/G GEAR NOT DOWN ecam?
3 circumstances
-Landing gear is not downlocked below 750’ RA with both engines operating below 75% N1, or if single engine, the remaining engine is operated below 97% N1
-Landing gear is not downlocked below 750’ RA and both engines are not at takeoff power with flaps selected to 1, 2, 3, or FULL
-Landing gear is not downlocked and flaps are selected to 3 or FULL with both radio altimeters failed
50
How do you use the hand crank to extend the gear?
Pull up on the hand crank until it locks in place, rotate it clockwise 3 times, and then place the landing gear lever into the DOWN position if not done already (this will extinguish the UNLK lights in the LDG GEAR indicator panel to provide a correct down and locked indication).
51
What does each clockwise rotation of the landing gear hand crank do?
1st rotation = The hydraulic shut off valves close, which isolates green hydraulic pressure from the system
2nd rotation = The gear door uplocks release, and the doors open
3rd rotation = The landing gear uplocks release and gravity causes the landing gear to extend (locking springs assist the main gear to the locked position, and aerodynamic forces assist the nose gear in locking)
52
What assists the main gear in extending to the locked position?
Locking springs
53
What assists the nose gear in extending to the locked position?
Aerodynamic forces
54
What will happen to the gear doors after gravity extending the gear?
They will remain down since there is no hydraulic fluid to assist in their retraction
55
What is the nosewheel steering controlled by?
It’s electrically controlled by the dual channel Brake and Steering Control Unit or BSCU
56
What happens if one channel of the BSCU fails?
The other channel automatically takes over
57
What sends commands to the BSCU?
-Two steering hand wheels
-Rudder pedals
-Autopilot (to track the localizer during an autoland)
58
What automatically centers the nose gear after takeoff?
The internal centering cam.
59
What must happen in order for the internal centering cam to center the nose gear after takeoff?
The nose gear strut must be extended
60
How does the BSCU control the nosewheel steering?
By controlling the nose wheel steering cylinder which is powered by the yellow hydraulic system
61
When does the N/W STEER indication on the WHEEL page turn amber?
-Nosewheel steering is lost
-Both BSCU channels fail
-Yellow hydraulic system pressure is low
-A/SKID and N/W STRG switch is OFF
62
What’s the maximum angle the hand wheels can command the nose gear to turn?
75º
63
Up to what speed is full handwheel steering authority available?
20kts groundspeed
64
How does handwheel steering authority change with ground speed?
You have full authority (75º) up to 20 knots GS, and then it decreases linearly to 0º at 80 knots GS
65
What happens if both handwheels are moved simultaneously?
The combined input is summed, and sent as a command to the BSCU
66
How much nose wheel steering is available through the rudder pedals?
+/- 6º up to 40 knots groundspeed and then decreasing linearly until you reach 0º at 130 knots groundspeed
67
During an autoland approach, until when is steering commanded to track the localizer?
Until the autopilot is disconnected. This is usually done via the side stick disconnect buttons but can also be done if significant handwheel or rudder pedal inputs are made.
68
What happens when the towing control lever is placed in the TOWING position?
The nosewheel steering is inhibited
69
In what position is the towing control lever when in the TOWING position?
The lever is vertical
70
What message is displayed when the nosewheel steering is disconnected via the towing control lever? Will you get the same message if you select the A/SKID & NW STRG switch to the off position?
NW STRG DISC is displayed when the lever is in the TOWING position. This message is NOT displayed when the nosewheel steering is commanded off with the A/SKID & NW STRG switch.
71
When does the N/W STRG DISC memo turn amber?
When at least one engine is running
72
What protects against tire burst in the event of an overheat?
Fusible plugs
73
Is the braking system designed to hold the aircraft in a stationary position when high trust is applied?
No. If high thrust is required on the ground care should be taken to ensure the aircraft remains stationary, and the thrust levers must be immediately retarded to idle if the aircraft begins to move.
74
Which hydraulic system provides pressure for the normal brakes?
Green system
75
Which hydraulic system provides pressure for the alternate brakes?
Yellow system
76
Do the rudder pedals directly control the brakes?
No. They send electronic commands to the BSCU, which in turn commands hydraulic pressure to clamp the brakes.
77
When is the normal braking system automatically selected?
When the green hydraulic system pressure is available and the A/SKID & N/W STRG switch is selected ON
78
When is the alternate braking system (with anti-skid) automatically selected?
It’s automatically selected when the green hydraulic system is lost and:
-yellow hydraulic pressure is available
-A/SKID & N/W STRG switch is in the ON position
-Parking brake is not set
79
What controls the alternate braking system?
The Alternate braking control unit (ABCU)
80
How does the aircraft modulate braking pressure?
By modulating the NORMAL servo valve, or the ALTN servo valve, depending on whether normal or alternate braking is in use
81
Can the auto brake function when the alternate braking system is in use?
No
82
What controls the anti-skid function when alternate brakes with anti-skid is active?
The BSCU
83
Is brake pedal displacement the same for normal and alternate brakes?
No. Pedal displacement in the alternate mode produces MORE braking action than in the normal mode.
84
When is alternate braking without anti-skid activated?
-When the A/SKID & N/W STRG switch is selected OFF
-When both BSCU’s fail
-When the yellow and green hydraulic systems have failed
85
If both the yellow and green hydraulic systems have failed, is braking still possible?
Yes. Through the yellow system brake accumulator.
86
How many brake applications are available from the yellow system brake accumulator before teh accumulator becomes depressurized?
7 applications
87
Do you have to press the brake pedals to activate the parking brake?
No
88
Is the parking brake signal processed through the BSCU’s?
No
89
Which braking systems are deactivated when the parking brake is set to on?
Both the normal and alternate brakes are deactivated, and the brake pedals have no effect
90
How long should a fully charged accumulator maintain parking brake pressure?
At least 12 hours
91
What sends brake temperatures to the WHEEL page?
The BSCU does, which in turn gets its information from temperature sensors in each brake
92
When does a green arc appear above a brake on the wheel page?
The green arc appears above the hottest brake, and only when the temperature exceeds 100ºC
93
When does the HOT light on the BRK FAN pushbutton illuminate?
If a brake temperature exceeds 300ºC
94
When is anti-skid operable?
When the A/SKID & N/W STRG switch is selected to ON and the BSCU is functional
95
How can the BSCU detect when a wheel skid is about to occur?
The BSCU can detect an impending wheel skid by comparing data it receives from wheel tachometers (to know the wheels rotational speed) and the ADIRS (to know the aircrafts forward speed)
96
What does the BSCU do if it detects an impending skid?
It sends a release signal to the normal and alternate brake servo valves for the wheel
97
What measures the rotational speed of the wheels?
Wheel tachometers
98
What do the green bars next to the wheel numbers on the WHEEL page indicate?
The anti-skid system of each brake. The appear in flight to indicate that the wheel brakes are released and will remain so until touchdown. They also indicate that the anti-skid function is armed. During the landing roll the bars disappear when braking occurs. They then reappear when an anti-skid release order is sent to the respective brake.
99
When does the ON light illuminate on the AUTO BRK push buttons after they’ve been pressed?
When the system is armed and all of the following are met:
-Green hydraulic pressure is available
-The anti-skid system is electrically powered
-No failures exist in the braking system
-At least one ADIRU is available
100
What is required to send the ground spoiler signal after landing?
-2 SEC’s must be operative
-Both main gear must be compressed
-And main gear wheel speed must be greater that 72 knots
101
How are MAX autobrakes deactived?
Any of the following
-Applying brake pressure to either brake
-Pressing the MAX AUTO/BRK pushbutton
-After the aircraft becomes airborne
-One or more f the arming conditions becomes lost
-Retracting the ground spoilers
102
Under what conditions will the signal to the spoilers be sent during a rejected takeoff?
When the thrust levers are moved to idle, AUTO brakes are set to max, the spoilers are armed, and speed is great then 72kts
103
What triggers the signal to be sent to the spoilers during a rejected takeoff, assuming all necessary conditions are met?
Retarding the thrust levers to idle
104
When will MAX autobrakes activate on the ground?
When the ground spoilers are deployed. That’s why we do our flight control check before selecting autobrakes to MAX.
105
When MED is selected, when do the autobrakes begin braking during landing?
2 seconds after the spoiler deployment signal is triggered
106
When LOW is selected, when do the autobrakes begin braking during landing?
4 seconds after the spoiler deployment signal is triggered
107
When is the spoiler deployment signal triggered during landing?
When both main gears are compressed and the wheel speed is greater than 72kts
108
What does the green DECEL light indicate on the AUTO BRK panel?
Deceleration has achieved 80% of the desired rate
109
When do the ground spoilers partially extend during landing?
When reverse thrust is selected on at least one engine with the other at idle, and one main landing gear is compressed. Once the other main gear is compressed full extension should occur.
