Landing gear and brakes

Tricycle gear moved by the left hydraulic system, carbon brakes with anti-skid on the main wheels, and steer-by-wire nosewheel steering.

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How it moves

Gear and steering

LANDING GEAR panel. Top row under TAWS WARN: GS, FLAPS and TERRAIN guarded OFF switches. Below: the NWS switch on the left and the LANDING GEAR handle on the right, with UP VLO 200 above it and DN VLO 250 VLE 250 below it.
LANDING GEAR panel: the gear handle with its speed placards, and the NWS switch. Tap to enlarge
Nosewheel steering tiller: a looped black handle on a round hub with a white pointer and centre and left and right marks, on a grey mounting plate.
Nosewheel steering tiller, on the pilot's side panel. Tap to enlarge
  • Two main gears and a steerable nose gear, with twin wheels on each.
  • The left hydraulic system moves the gear. The main gears retract inward and the nose gear forward.
  • The PSEU reads the LANDING GEAR handle, the proximity sensors and weight on wheels, then drives the selector valve.
  • During retraction the BCU holds 350 psi on the brakes for 4 s, so the main wheels stop spinning before they enter the bay.
  • After takeoff the PSEU disarms the normal brakes and the nosewheel steering. The steering re-arms at touchdown.
  • EICAS shows a DN icon for each gear down and locked. A red gear icon with the GEAR warning means you are landing with a gear not down and locked.
Steering
NWS switch (LANDING GEAR panel)Arms the steering. The switch is lit when OFF.
Tiller (pilot's side panel)Full authority, ±65° at the nosewheel
Rudder pedalsLimited authority, ±7° at the nosewheel
Steering works withleft hydraulic pressure, nose gear down and locked with weight on wheels, NWS on
NWS off or failedThe nosewheel casters freely.

How it stops

Brakes and anti-skid

PARK/EMER BRAKE handle on its pedestal panel, seen from above, with a red and white striped grip. Beside it two side views of the handle: STOWED, lying flat, and SET, pulled up.
PARK/EMER BRAKE handle on the centre pedestal, stowed and set. Tap to enlarge
  • Carbon multi-disc brakes on every main wheel. Left hydraulics brake the inboard wheels, right hydraulics the outboard wheels, each channel with its own electrical source.
  • Both pilots have full and differential braking. The BCU uses whichever pedal input is greater.
  • The brakes arm when the gear is selected down or ground mode is detected.
  • Anti-skid works on each main wheel down to 10 kt, with touchdown and locked-wheel protection.
  • Each main wheel has four fusible plugs. They melt if the wheel gets too hot and let the tyre deflate before it can burst.
  • An overheat loop in each main wheel bin triggers GEAR BAY OVHT.
PARK/EMER BRAKE
Handle (centre pedestal)Pull up until it latches to park. To release, pull up, press and hold the button, and let it go down.
Used forParking, or braking when the normal brakes are inoperative
What it brakesAll four main wheels, with no differential braking and no anti-skid
Accumulator (left hydraulic system)Extended parking, or at least 6 emergency brake applications
INBD BRAKE PRESS LOInboard accumulator below 1,400 psi
OUTBD BRAKE PRESS LOOutboard accumulator below 1,400 psi
PK/EMER BRK PRESS LOBelow 1,200 psi: not enough for full PARK/EMER BRAKE. Normal brakes still work.

What not to exceed

Limits and abnormals

Manual release system: cutaway of the forward fuselage showing the cable run, the red LG PULL / PUSH FULLY TO STOW handle in detail B, and cables from the main quadrant to the NLG uplock, both MLG uplocks, the runaround and dump valve, and the dump and manual selector valve.
Manual release system: the LG PULL handle and the cables to the three uplocks. Tap to enlarge
Key numbers
VLO, retraction200 KIAS
VLO, extension250 KIAS
VLE250 KIAS
Gear extensionprohibited above 18,000 ft
Tyre speed182 kt ground speed maximum
Towing, torque links connected120° either way at the nose gear. Beyond that: NWS LIMIT EXCEEDED and possible damage.
Brake coolingobserve the cooling times between a landing or RTO and the next takeoff
  • Alternate extension: the LG PULL handle, at the rear of the centre pedestal on the copilot's side, releases the uplocks. It works after a gear control or left hydraulic failure.
  • The nose gear falls by gravity and springs. The main gears fall by gravity, and right hydraulic pressure, backed by an accumulator, helps them into their downlocks.
  • GEAR DISAGREE: a gear is still in transit after 28 s, or does not match the handle.
  • GEAR SYS FAIL: the gear control has failed completely. Gear, door and spoiler indications may be lost.
  • NORM BRAKES FAIL, with the aural "NORMAL BRAKES FAIL": all normal pedal braking is lost.

The full module

The slides take you through the gear, steering, brakes and the abnormals, then a 10-question test.

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