TRIM-AIL circuit breaker if the malfunction
is isolated to the roll trim system.
There are no CAS or CWP indications for
the aileron trim system and there is no back-
up aileron trim system. A normal approach
and landing can be made with only light con-
trol force applied to overcome a full roll trim
condition.
Aileron Augmentation
The spoilerons provide full-time roll aug-
mentation and for backup roll control in the
event of a jam in the aileron control system.
The spoilers (Figure 15-8) are electrically
controlled and hydraulically actuated. The
spoileron computer receives roll commands
f r o m t w o R o t a r y Va r i a b l e D i f f e r e n t i a l
Transformers (RVDTs) located in the hub of
the pilot's control wheel. The spoileron com-
puter then deploys each spoileron surface ac-
cording to a schedule, depending on flap
position, airspeed, etc.
Aileron Disconnect
In the unlikely event that the aileron controls
become jammed, the pilot's control wheel can
be disconnected from the aileron control ca-
bles and airplane roll can be controlled with
spoilerons alone. Pulling the roll disconnect
actuation lever on the pilot's control wheel
(Figure 15-9) to the full aft position mechan-
ically disengages a clutch within the control
w h e e l h u b a n d t r i p s t wo r o l l d i s c o n n e c t
switches that signal the spoileron system. The
copilot's control wheel will remain connected
to the aileron control system. A "ROLL DISC"
message will be posted on the CAS when roll
disconnect is actuated. The “ROLL DISC”
CAS message is amber on the ground and
white when the aircraft is airborne.
Two Rotary Variable Differential Transformers
(RVDTs), also located in the pilot's control
wheel hub send continuous information to the
spoileron computer indicating pilot's control
wheel position. The RVDTs provide signals
to the spoileron computer for normal full time
spoilerons, but when the ailerons are discon-
nected, the operation changes slightly.
Artificial friction is introduced into the pi-
lot's control wheel upon disconnection to pro-
vide some level of pilot feel. If the autopilot
is engaged when roll disconnect is activated,
it will disengage and cannot be re-engaged as
long as roll disconnect is activated.
15-8
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
Figure 15-8. Spoiler/Spoileron
(Left Wing)
ROLL
DISC
Learjet
ROLL DISCONNECT LEVER
PILOT'S CONTROL WHEEL
ROLL
DISC
Figure 15-9. Roll Disconnect Lever on
Pilot’s Control Wheel