Landing Gear/Brakes Flashcards
Gear Position Disagree light (amber)
Gear position disagrees with the lever position
Landing Gear Lever positions
UP - pressurizes UP hydraulic lines
DN - pressurized Down hydraulic lines
OFF - removes hydraulic press from system
Nose gear deflection by rudder and steering tiller
Rudder - 7º
Nose Wheel Steering tiller - up to 65º
AUTOBRAKES Light (amber)
Autobrakes are disarmed or inoperative
Autoborake RTO
automatically applies maximum braking pressure
- above 85 knts groundspeed
- thrust levers idle
Brake Source Light
Both normal and alternate brake system pressure is low
Reserve Brake Switch ON
- Allows use of reserve right hydraulic fluid
- Activates right electric hydraulic pump
- Isolates the right electric hydraulic pump power to the normal brake system
Hydraulic power source for brakes
Normal and Reserve Brakes - Right hydraulic system (757)
Alternate brakes - left hydraulic system (757)
Normal Brake - Right hydraulic (767)
Alternate and Reserve Brakes - Center hydraulic (767)
How does air/ground sensing system receive air/ground logic signals
Tilt sensor on each main gear
- configure aircraft systems to appropriate air/ground status
Nose gear strut compression sensors
- for stall warning and portions for caution and warning system
Landing Lever Lock
- automatically locks landing gear lever on the ground-
- controlled by main gear tilt sensors
- manual override switch
Landing Gear Normal Retraction
- both main gear tilt after takeoff releasing lever lock
- lever in Up position pressurized lines and starts retraction
- Gear and Door lights illuminate showing gear in transit (gear, door, and lever position disagree)
- Gear doors open and landing gear retracted into position
- gear and doors held up by up locks (757); rest on gear doors (767)
Alternate Gear Extention (757)
- Alt Gear extend switch selected ON
- battery bus powers a DC electric pump
- trapped fluid in the supply line release all gear doors and uplocks
- gear free-fall to down and locked position
- Gear doors remain open (GEAR DOORS light displays)
Components of Brake System
- Normal/reserve brake hydraulic system
- Alternate brake hydraulic system
- Brake accumulator
- Anti-skid protection
- Autobrake system
- Parking brake
When does Alternate Braking become active?
- selection of alternate braking is automatic
- powered by left hydraulic system
- if right hydraulic pressure becomes low
Back up braking if Normal/Reserve and Alt braking are lost
braking supplied by accumulator
- can provide several brake applications and parking brake application
Anti-Skid Protection system
Provides Anti-skid, locked wheel, touchdown, and hydroplaning protection
- anti-skid valves reduce brake pressure
- normal/reserve brakes provide anti-skid to each main gear wheel
- alt braking provides anti-skit to laterally paired wheels
When are autobrakes automatically supplied?
- one of fives levels of deceleration selected (1, 2, 3, 4, MAX AUTO)
- aircraft on the ground with wheel spin up
- thrust levers idle
- selected deceleration level occurs when pitch angel is less than 1º
When will Autobrake automatically disarm
- brake pedal application
- either thrust lever advanced after landing
- speed break lever to full up after being deployed
- DISARM or OFF selected
- autobrake fault
- Normal anti-skid faul
Landing Gear and Brake hydraulic source (767)
Landing Gear and Steering - Center Hydraulic system
Normal Brakes - right hydraulic system
Alternate Brakes - Center Hydraulic system
Reserve Brake and Steering Switch (767)
Selected ON:
− Turns on center hydraulic system #1 electric pump regardless of switch position – and –
− Provides pressure to alternate brake system – and –
− Provides pressure to nosewheel steering system
− Isolates Center Hydraulic system fluid
When are brake temperature readings accurate (767)
10-15 mins
Tailskid system (767)
- extends for takeoff and landing
- helps protect the pressurized part of the aircraft from contract with the ground
Alternate Gear Extension (767)
− Alternate gear extension uses battery bus to power an electric motor that uses a cable to
release the nosegear uplocks and main gear door locks
Normal gear extension airspeed limit
270 kts/0.82M
Alternate gear extension airspeed limit
250 knts/0.75M
Reserve Brakes and Steering system (767)
Inflight, if center hydraulic system quantity sensed low, system automatically:
− Closes Isolation valve ♦ Shuts off center hydraulic system pressure from all components except: ◊ Reserve brakes – and – ◊ Nosewheel steering − Opens Supply valve ♦ Supplies center system standpipe protected fluid to: ◊ Reserve brakes – and – ◊ Nosewheel steering
