Landing Gear and Brakes

Question 1

How is landing gear controlled?

Answer 1

Electrically controlled, hydraulically
actuated, and electrically sequenced

Question 2

What does the white light indicate in
gear handle?

Answer 2

Disagreement between landing gear
handle and the gear

Question 3

What’s the meaning of magenta gear
indication on flight control synoptic
page?

Answer 3

Gear in transit

Question 4

What functions are performed from
Landing Gear Control Maintenance
Panel (LGCMP)?

Answer 4

Used to open/close gear doors, retract or
extend the gear when jacked, and change
WOW status

Question 5

What’s the purpose of the landing
gear LOCK RELEASE button?

Answer 5

It allows landing gear handle to be placed
in UP position regardless of WOW mode

Question 6

What’s the normal source of
hydraulics for opening and closing
gear doors on the ground?

Answer 6

Aux pump (in the absence of hydraulic
pressure from left system) through
LGCMP

Question 7

What’s the caution associated with
gear doors once they’re opened for
preflight?

Answer 7

Always pin the doors open when
movement is not desired

Question 8

After opening the gear doors for
preflight, what must be accomplished
to put the airplane back into “ready
for flight mode?”

Answer 8

Close all gear doors and select Normal on
LGCMP; otherwise, plane will remain in
MX mode and gear will not retract on
departure.

Question 9

What’s the location of the nitrogen
bottles used for emergency landing
gear extension?

Answer 9

There are two (2) bottles: one located on
each side of the nose wheel well

Question 10

What’s the pressure on a fully
serviced emergency landing gear
extension bottle?

Answer 10

3,000 psi at 70°F/21°C; enough for only
one extension of landing gear

Question 11

What happens to uplocks when left
hydraulic system pressure is applied
during gear retraction?

Answer 11

They move to correct position

Question 12

What happens if an uplock is found in
wrong position during preflight and
aux pump pressure is applied?

Answer 12

The hook snaps to correct position: there’s
no preflight requirement to make sure
they’re open.

Question 13

What happens if you takeoff with nose
and main gear downlock safety pins
installed?

Answer 13

Gear will not retract

Question 14

What’s the purpose of disconnecting
torque link from NWS unit during
towing?

Answer 14

It prevents damage to NWS unit from over
travel. With steering unit torque links
disconnected, nose wheels are free to
rotate 360°

Question 15

Describe WOW system.

Answer 15

Two proximity sensors are installed on
each landing gear and provide WOW
indications.

Question 16

How many landing gear dump valves
are there?

Answer 16

Two: one for nose and one for mains

Question 17

After performing an emergency
extension, Nose Gear and Main Gear
illuminates in blue inside Dump Valve
switches. What does this indicate?

Answer 17

After performing an emergency
extension, Nose Gear and Main Gear
illuminates in blue inside Dump Valve
switches. What does this indicate?

Question 18

What happens when Dump Valve
switches are pressed?

Answer 18

Dump valves are electrically placed in
hydraulic position and blue switch labels
change to white

Question 19

Describe what happens when EMER
LDG GEAR handle is pulled?

Answer 19

Emergency air release valve opens and
releases compressed nitrogen into landing
gear extension system

Question 20

What happens when EMER LDG
GEAR handle is returned to stowed
position?

Answer 20

Nitrogen pressure releases from actuators
and exhausts overboard through vent on
right side of nose wheel well adjacent to
NLG doors

Question 21

What’s the position of landing gear
doors following an emergency
extension?

Answer 21

Open

Question 22

Describe sources of hydraulics for
normal braking.

Answer 22

Inboard brakes are powered by hydraulics
from left system, PTU or aux system.
Without source of hydraulics, inboard
accumulator is available for use through
toe brakes as well as parking brake.
Outboard brakes are powered by
hydraulics from right hydraulic system.
Without source of hydraulics, outboard
accumulator is available for use through
toe brakes as well as parking brake.

Question 23

Describe sources of hydraulics for
parking brake.

Answer 23

Parking brake uses pressure from left and
right hydraulic systems (i.e., left system
for inboard and right system for outboard).
In the absence of left or right system
pressure, it uses accumulator pressure
which is charged from left and right
hydraulic systems. Important note: if you
select AUX pump to ON during ground
operations without engines running, only
the left (inboard) parking brake
accumulator is charged.

Question 24

What happens if both pilots are
providing brake input?

Answer 24

Greater input wins

Question 25

With RTO enabled for takeoff, when
would you get anti-skid limited
braking during an abort?

Answer 25

> 80 knots

Question 26

What’s the purpose of brake fuses?

Answer 26

They shut off applied brake fluid in case
of line rupture and fluid loss downstream

Question 27

Each MLG wheel has dedicated brake
assembly which functions as normal
toe brakes and parking brakes. What
other functions do they perform?

Answer 27

Provides main wheel de-spin during
retraction of landing gear

Question 28

When parking brake is set, what
component ensures the pressure
coming from outboard accumulator is
equal to or slightly less than pressure
coming from inboard accumulator?

Answer 28

Repeater valve

Question 29

How is brake life determined during
preflight?

Answer 29

“Life remaining” is determined by wear
pin indicator (2 per brake assembly)
attached to the end of stator. The amount
of protrusion indicates the amount of life
remaining in heat stack (parking brake
must be set for proper indication).

Question 30

How does basic antiskid work?

Answer 30

It’s accomplished by comparing individual
wheel deceleration rates to predetermined
ideal reference deceleration

Question 31

Below what speed is antiskid
protection not available?

Answer 31

10 knots

Question 32

How does touchdown protection
work?

Answer 32

Zero brake pressure is applied until wheel
speed > 70 knots or WOW plus five (5)
seconds.

Question 33

Why is brake pressure applied during
gear extension and retraction?

Answer 33

During gear extension to check system
health and during retraction to control rate
of wheel spin down

Question 34

What does Gulfstream recommend to
hold the aircraft for extended periods
of time?

Answer 34

Always chock the aircraft: parking brake
is not designed to hold aircraft for
extended periods of time.

Question 35

What happens if nose wheel steering
power is selected to OFF?

Answer 35

Nose wheel is free to caster in passive
mode, responding to tracking forces of
differential braking or engine power
settings

Question 36

What happens when pedal steering
switch is selected to OFF?

Answer 36

Rudder pedal steering is disabled

Question 37

What does a NWS popped overtravel
indicator indicate?

Answer 37

That steering unit was forced beyond
normal travel range and maintenance is
required

Question 38

What’s the purpose of variable gain?

Answer 38

It helps to prevent the pilot from over
controlling the nose wheel steering.