board horn of each control wheel. The CWTSs
consist of a barrel switch which can be moved
forward and aft (NDN - NUP) for pitch trim
and left and right (LWD - RWD) for aileron
trim and is spring-loaded to the center posi-
tion (Figure 15-3, page 15-4). To complete
the trim command circuit, the arming switch
(button) on top of the barrel must be depressed
simultaneously with movement of the barrel.
Trim commands from the pilot’s CWTS will
override commands from the copilot’s CWTS.
Primary trim speed is variable and is auto-
matically controlled by the #1 IC-600. The
IC-600 uses airspeed information from both
ADCs to schedule trim speed and Mach trim.
The #1 IC-600 sends the primary trim com-
mands to the primary trim actuator. The trim
actuator and the IC-600 both monitor the trim
operation.
The primary trim actuator performs a power-
up circuit check. If the actuator detects a fault
during the power-up check a white “PRI TRIM
FAULT” message is posted on the CAS (Table
15-1). Primary trim will be still available with
the “PRI TRIM FAULT” CAS message dis-
played, however, operation may be at a low
trim rate and configuration trim and Mach
trim may be inoperative depending on the mal-
function.
The primary trim actuator and #1 IC-600 both
monitor primary trim operations for a number
of possible malfunctions including uncom-
manded trim and trim in the wrong direction.
If either of these malfunctions is detected by
the trim actuator, an amber “PRI TRIM FAIL”
message is posted on the CAS and primary trim
is disabled (Table 15-1). This monitoring is
also functional for configuration trim and
Mach trim operation. If primary trim is dis-
abled, the operator must then use the sec-
ondary trim system.
If uncommanded trim, trim in the wrong di-
rection, or incorrect trim rate is detected by the
#1 IC-600 a white “PRI TRIM FAULT” CAS
message is displayed, and primary trim will re-
vert to IC-600 bypass trim. The same moni-
toring function by the IC-600 takes place dur-
ing configuration trim and Mach trim opera-
tion.
Primary Bypass Trim
Primary trim reverts to bypass as a result of a
detected malfunction or #1 IC-600 failure and
is not crew selectable. When in bypass trim,
a white “PRI TRIM FAULT” CAS message is
displayed and CWTS commands go directly to
the primary trim actuator, bypassing the IC-
600. The #1 IC-600 trim functions primary
trim, configuration trim, and Mach trim are all
disabled in this case.
When the “PRI TRIM FAULT” CAS message
is illuminated, depressing and releasing the
MSW may clear the fault. Refer to the PRI
T R I M FAU LT p r o c e d u r e i n t h e A F M o r
Checklist.
When in bypass trim, the primary trim actua-
tor operates at only two speeds (high or low).
The speed depends on flap position. If the flap
signals do not agree, the rate of trim function
is limited to slow speed. Both flap signals
must agree and must indicate flaps are greater
than 3° for the actuator to operate at a high rate.
When the flaps are up (< 3°), primary bypass
trim will be at a slow rate.
The primary trim actuator continues to mon-
itor for uncommanded trim and incorrect trim
direction in the bypass trim mode. It also mon-
itors for the correct trim speed based on flap
position. If it detects a failure in any of these
areas, primary trim is disabled and the amber
“PRI TRIM FAIL” CAS message is displayed.
Configuration Trim
The #1 IC-600 receives spoiler and flap po-
sition information from the DAUs for con-
figuration trim. When the position of the
spoilers or flaps is changed, the #1 IC-600 en-
ergizes the primary trim actuator motor and
m ove s t h e h o r i z o n t a l s t a b i l i z e r a p r e s e t
amount to account for the change in pitch at-
titude. Configuration trim moves the stabi-
lizer at a rate to match the pitch moment
15-16
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