When the roll disconnect mode is activated
within the spoileron computer, it outputs a
signal to cause the “ROLL DISC” message to
be posted on the CAS (Table 15-1). The “ROLL
DISC” CAS message will be amber on the
ground and white inflight.
The roll disconnect mode provides roll control
through RVDT signals from the pilot’s control
wheel to the spoileron computer. This mode is
much the same as the normal spoileron mode
but has a different gain curve relating to con-
trol wheel input and panel deflection. Also, in
this mode, response to control wheel deflec-
tion begins at 1° movement instead of 5°.
Spoilers can be operated in conjunction with
the aileron disconnect mode the same as they
are with the normal spoileron mode. The au-
topilot is not usable when roll disconnect is ac-
tivated. Depressing the MSW will not affect
spoileron operation while in the roll discon-
nect mode.
The roll disconnect mode may be deactivated
in flight after matching the position of the
control wheels and returning the roll discon-
nect lever to its normal (forward) position.
Spoiler Monitor System
The spoileron computer contains a monitor
system to prevent electrical or mechanical
faults from causing uncommanded extension
or retraction of the spoilers.
The spoileron computer performs a self-test
(BITE) at power-up. A test failure will trip the
spoileron monitor. If the monitor detects a
self-test failure or a fault during normal op-
eration, hydraulic pressure is removed from the
system by closing the spoiler shutoff valve
(Figure 15-21). A hydraulic return is provided
so that spoilers can blow closed. During nor-
mal operation, the shutoff valve is held open
with an electrical solenoid. Power failure will
also cause the valve to close.
In the event a spoiler/spoileron malfunction oc-
curs where the monitor does not stow the spoil-
ers, the crew can initiate the stow with either
MSW. When either MSW is held depressed, the
spoiler shutoff valve is depowered closed and
the spoilers should blow down to a “float” po-
sition of approximately 10°.
When a malfunction causes the spoileron mon-
itor to trip, an amber “SPOILERS FAIL” mes-
sage is posted on the CAS. If a spoiler surface
deploys uncommanded due to a malfunction,
or deploys further than commanded, the mon-
itor system should cause the spoiler to retract
and generate a “SPOILERS FAIL” CAS. If
there is uncommanded roll, the
AFM
/Checklist
provides a Roll or Yaw Axis Uncommanded
Motion procedure. If the malfunction was mo-
mentary or has cleared, it may be possible to
reset the spoileron computer using the “SPLRN
RESET” position on the system test knob
(Figure 15-19).
If the monitor detects a jammed spoiler, the
spoileron computer continues to operate using
the spoiler that is not jammed and it applies a
full retract input to the affected actuator for 5
to 7 seconds. It also causes the amber “L or R
SPOILER JAM” message to be posted on the
CAS. If the jammed spoiler will not retract, the
AFM
procedure is to try to match the operat-
ing spoiler position with the jammed spoiler
using the spoiler lever and the FLT system
schematic display. The MSW should not be
held depressed with this malfunction. If the
fault cannot be cleared, the
AFM
provides a
procedure for landing with one or both spoil-
ers deployed.
Spoiler Electrical Power
The spoileron computer uses electrical power
from the L Essential Bus for operation and
the spoiler indicating system uses power from
the R Essential Bus as depicted in Figure 15-
21. The circuits are protected by the SPLR
CTRL and SPLR IND circuit breaker, re-
spectively, located in the FLIGHT group on the
pilot’s and copilot’s circuit breaker panels.
If power to the spoileron computer is lost
through the SPLR CTRL circuit breaker, the
spoilers will retract and be inoperative in all
modes. If power is lost through only the SPLR
IND circuit breaker, spoilerons will be oper-
ational in only the roll disconnect mode.
15-29
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