The steering authority decreases from a max-
imum 60 degrees authority at the beginning of
takeoff roll and gradually decreases to 7 de-
grees authority at approximately 70 KIAS as
the airplane accelerates for takeoff. The au-
thority limit then remains at 7 degrees to lift-
off. On landing, steering authority will initially
be limited to 7 degrees left or right after touch-
down and as the airplane decelerates, the au-
thority will gradually increase to 60 degrees
at the lowest ground speeds.
Fade-in is provided to ensure smooth transi-
tion from the disengaged to the engaged mode
and allows the pilot adequate time to respond
to steering effects on the aircraft. The fade-in
gradually increases steering rate over a few
seconds until the maximum rate of 22 degrees
per second has been reached.
The steering system has an out-of-range re-
covery feature. If the system is engaged out of
the normal operating range of 60 degrees left
or right, the system will drive the wheel at 35
degrees/second in a direction, which represents
the shortest path to an operational range.
NORMAL OPERATION
The nose wheel steering system is normally se-
lected ON prior to taxi by momentarily de-
pressing the NOSE STEER switch. When the
system is armed, “ON” will be illuminated in
the NOSE STEER switch/indicator. To dis-
arm/disengage the NWS on the ground, mo-
mentarily depress either control wheel master
switch (MSW) or momentarily depress the
NOSE STEER switch. Depressing either
wheel master switch while in flight does not
cause the NWS to disarm, but it can be dis-
armed in flight after the landing gear is low-
ered by momentarily depressing the NOSE
STEER switch.
The nose steering should remain engaged
throughout takeoff. After lift-off, the nose
wheel steering computer commands a 2 sec-
ond nose centering signal, then disconnects
power to the servo actuator. When the landing
gear is retracted, the NOSE STEER “ON” leg-
end will extinguish. When the nose gear is
down and locked for landing, the “ON” leg-
end will illuminate in the NOSE STEER
switch/indicator if power to the nose steer
computer has not been interrupted in the in-
terim. The system is armed when the “ON” leg-
end is illuminated and when the aircraft is on
the ground the nose wheel steering will engage.
DEGRADED MODE OF
OPERATION
The nose wheel steering system is designed to
fault under some malfunction conditions rather
than fail. This increases nose wheel steering
availability and minimizes the probability that
certain system malfunctions remain latent.
When a fault is detected, a white “NWS
FAULT” CAS message will be posted on the
EICAS. System operation will be degraded
with this CAS message displayed and steer-
ing authority may be limited. The “NWS
FAULT” CAS message may indicate a loss of
pedal force steering. Significantly larger turn
radius may result and must be planned for. In
the event that a NWS fault (white “NWS
FAULT”) or failure (amber “NWS FAIL”) is
annunciated on EICAS, depressing and re-
leasing the NOSE STEER switch/indicator
will initiate a reset of the NWS computer in
an attempt to clear the fault/failure.
For some nose wheel steering system mal-
functions, internal monitors are programmed
to disconnect the system and illuminate the
amber “NWS FAIL” CAS message. A nose
wheel steering malfunction may be accompa-
nied by an unwanted swerve. If this should hap-
pen during taxi, maintain directional control
using differential braking and if the computer
monitor has not already disengaged the steer-
ing, disengage it using either control wheel
master switch (MSW). Taxi without steering
is possible using differential braking and
thrust. Avoid sharp turns, since it may not be
possible to straighten the nose wheel by dif-
ferential braking alone.
14-25
FOR TRAINING PURPOSES ONLY
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
FlightSafety
international
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
FlightSafety
international