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prevents draining low output of electric pump or accidentally powering Green
Hydraulic)
Parking brake is ON and only one ENG MASTER switch is ON
PTU pb is off
Note: If a cargo door is operated and then the 2nd engine is started within 40
seconds a PTU fault message may be given (due to inhibition during test period).
The engine pumps (Green and Yellow) each have Fire Shut Off Valves that close
when the Engine Fire Pushbuttons are selected open.
Brakes
The brakes are carbon, multidiscs actuated by two independent systems, Normal
and Alternate. The normal brakes are powered by the Green hydraulic system.
Normal brakes are available when:
The A/SKID & N/W STRG switch is ON
Green hydraulic pressure is available
The parking brake is OFF
A BSCU (Brake and Steering Control Unit) controls all normal braking functions
(anti-skid, autobrakes and brake temps.).
Normal brake pressure is 2000 - 2700 psi. w/ full pedal deflection
Anti-skid is deactivated below 20 kts. Anti-skid may or may not be available when
on alternate brakes. If antiskid is inop. then alternate brakes use 1000 psi max to
prevent blowing tires.
The alternate brakes are powered by the Yellow hydraulic system and will
automatically become selected if Green hydraulic is insufficient for normal
brakes. Yellow brakes have the same capabilities as normal brakes except for
autobrake capability. The alternate brakes are essentially a mechanical system.
Think - BSCU on: Normal GREEN - BSCU off: Alternate, YELLOW.
US Airways Airbus A319, A320, A321 Notes
25
Alternate brakes can be used with or without anti-skid. Anti-skid during alternate
brakes is inoperative when:
Electrical power failure
BSCU failure
A/SKID & N/W STRG switch turned off
Brake pressure supplied by Yellow accumulator only
Parking brake disables all other brake modes (319, 320 only). Parking brake is
on Yellow system.
A pressure indicator on the instrument panel indicates Yellow accumulator
pressure and Yellow left and right brake (parking brake) pressure on three
needles.
Accumulators maintain good parking brake pressure for at least 12 hrs. The
cargo door operation will restore parking brake (Yellow system) pressure.
Autobrakes are available on Normal Brakes (Green system) only. Hold pb for at
least one second. LO mode delays for 4 seconds after touchdown. MED mode
delays for 2 seconds. MAX has no delay. Do not use MAX for landing, MAX is
takeoff only (PH 3.12).
The Green DECEL light in the auto brake pb’s indicates actual deceleration is
within 80% of the selected rate (does not indicate that the autobrake is activated).
Autobrakes activate when ground spoilers are extended. On takeoff they are not
armed until 72 kts. 2 SEC’s are required for Autobrakes.
Brake Fans are installed in the main gear hubs. They will indicate an amber HOT
when the brakes are 300° C or more. Brake temps are shown on the ECAM
WHEELS page. An arc will appear above the hottest brake temp. If brake temp
is above 300° C then the temp will turn amber. The brakes must be cooled below
300° C before takeoff. Pilot must manually select brake fans on.
Note: Delay selecting Brake Fans on taxi in for at least 5 mins. or until at gate.
Carbon brakes actually wear better when heated, however if turn time is short or
if brakes will exceed 500° then cool immediately. Fans should only be used to
cool to about 250° C (PH 3.15)
US Airways Airbus A319, A320, A321 Notes
26
Hot Brakes (PH 3.15) Maintenance action is required if there is:
150° C difference in brake temps on the same strut and one brake 600° or
greater or 60° or less
a mean 200° C difference between different trucks
fuse plug melted
brake temp exceeds 900° C (800° C, A321)
Avoid use of the parking brake when brakes are 500° C or above if able.
Do not set Parking Brake ON in flight.
Landing Gear
The Airbus Landing Gear:
Has enclosed gear bays
Is held by mechanical uplocks
Uses manual extension by gravity
Has no mechanical or visual check for gear position
Uses autobraking on the mains during retraction
Has a brake band in the nose gear well
Is hydraulically locked out from operation above 260 kts.
The LGCIU controls the Airbus landing gear operation. The SD will show 2 green
down triangles on the WHEELS page for each gear down and locked. There are
also gear indicators next to gear handle. Any green triangle (at least one out of
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