曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
etc.).
In the absence of a pressurixed combined hydraulic
system, the wheelbrake accumulators can only be recharged
by the pilot hydraulic handpump with the landmg
gear handle in the down position.
Complete loss of hydraulic fluid through the
wheelbrake hydraulic lines will render parking
brake ineffective.
2.26.7 Wheel Antlrotatlon. Dmingtheinitialphase
of the landing gear r&action cycle, pressurized fluid
from the gear-up lines is directed to the power brake
module to displace the normal metering valves to stop
main wheel rotation before the wheels enter the wells.
This feature is not provided for the nosewheels.
Ebunination of indexer lights is not a positive
indication that the main landing gear is clear
oftherunway. Raisingthegearbeforeapositive
rate of climb is established will result in
blown main tires.
2.27 NOSEWHEEL STEERING SYSTEM
The electrohydraulic nosewheel steering system provides
for on-deck aircmft directional control, nosewheel
shimmy damping, and nosewheel cantering. The power
unit is located on the lower portion of the nose landing
gear shut outer cylinder, which, through a ring gear,
controls the dimctional alignment and damping of the
lower piston assembly.
Combined hydraulic system pressure is the motive
power used for steering and centering. Electrical power
is supplied t?om the essential dc bus with circuit proteotion
by the NOSE WHEEL STEEWAFCS circuit
breaker (RC2) on the pilot right knee panel. Hydraulic
pressure is derived from the gear-down line such that
steering control is disabled subsequent to emergency
extension of the landing gear (Figure 2-72).
Note
If nosewheel steering is inoperative, the
emergency gear extension air release valve
may be tripped, which will prevent gear
retraction.
2.27.1 Nosewheel Steering Control. Nosewheel
steeringc ontrol during ground operationsis onorgixedb y
momentarily pressing the autopilot reference and nosewheel
steering pushbutton on the lower forward side of
pilot stick grip (see Figure 2-72). The system carmot be
engaged without weight on wheels. The system will ro
main engagedu ntil weight is offwheels, electricalp ower
is interrupted,o r the pushbuttons witch is presseda gain
Engagement of nosewheel steering is indicated by illumination
ofthe NWS ENGA caution light. An automatic
nosewheel steering system disengage feature is provided.
If this feature has been activated by cycling the
hookondeckwiththethmttlesatidle,thenthenosewheel
steeringw ill be disengageda nd the NWS ENGA light
extinguished when the launch bar is lowered. The nose
wheel steering automatic disengage feature is deactivated
if the nosewheel steering button is depressed.
With the systeme ngaged,n osewheels teeringi s contmlled
by rudder pedal position. Centering is unaffected
by directional trim displacement. Maximmn steering
authority is 70” either side of neutral, and the nosewheel
can swivel a maximum of 120° about the centered position.
With greater weight on the nosewheel (wings forward,
high gross weight, etc.) the steering torque can
only tum the nosewheel +5” with the aircrag static.
However, only a slight forward movement will provide
the pilot with lull-power steering authority. In a full
pedal-deflection mm using nosewheel steering, the aircratt
pivots about a point between the main gear such
that the inboad main wheel rolls backward. Under this
condition, application of either main wheelbrake will
only serve to increase the radius of turn. Because of the
outboard location of the engines, the application of
thrust in tight turns should be made on the outboard
engine to etliciently complement the turning movement
of the nosegearN. osewheelc entering is enabledb y the
same latching relay that enables nosewheel steering
automatic disengagement with launch bar lowering.
Therefore, if the nosewheel steering is automatically
disengagedw hen the launch bar is lowered, the nosewheels
will be hydraulically centered,
2-125 ORIGINAL
NAVAIR 01-Fl4AAD-1
NOMENCLATURE FUNCTION
0
NWS ENGA caution light lllumlnatlon when nosewheel steering engaged and will respond as a
function of rudder pedal displacement. Nosewheel steering automatically
centers with hook down. Nosewheel centering requires throttles at IDLE and
weight-on-wheels with hook down.
0
Autopilot reference and Press to engage and disengage nosewheel steering. Requires
nosewheel steering weight-on-wheels.
pushbutton
0 Rudder pedals
Figure 2-72. Nosewheel Steering Controls
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F-14D 飞行手册 Flight Manual 1(126)
