Secondary Pitch Trim - BOMBARDIER LEARJET 40 Pilot's Manual

Pilot's Manual

SECONDARY PITCH TRIM

Secondary pitch trim is electrically independent of the primary trim,
configuration trim, and Mach trim. In the event of primary trim failure,
secondary pitch trim is available as a backup means of trimming the
airplane in the pitch axis. The autopilot also uses the secondary trim ac-
tuator as a normal means of trimming in the pitch axis. The autopilot
can use the secondary trim actuator with the trim selector in the PRI or
SEC position.
The dual-segment SEC trim switch (Figure 5-4) is located on the center
pedestal. Manual activation of secondary trim requires that the pitch
trim selector be in the SEC position and that both segments of the
spring-loaded SEC switch be moved at the same time. When SEC posi-
tion is selected, a CAS is displayed.
The secondary pitch trim actuator has a monitor function similar to the
primary actuator. It performs a power-up check and if any faults are de-
tected, a fault is displayed on the CAS, however, secondary trim oper-
ates normally. The secondary trim actuator also monitors for
uncommanded trim, trim in wrong direction, and incorrect trim rate. If
any of these malfunctions are detected, a fail annunciation is posted on
CAS and the secondary actuator is disabled. The IC has no control or
monitor functions for manual secondary trim.
The following CAS illuminations are specific to the secondary pitch
trim:
CAS
SEC TRIM FAIL
SEC PITCH TRIM
SEC TRIM FAULT
Electrical power for the secondary pitch trim system is provided from
the R ESS BUS and is protected by the TRIM-SEC PITCH circuit breaker
located on the copilot's circuit breaker panel (FLIGHT group).
5-18
Color
Amber Secondary pitch trim has failed.
White Secondary pitch trim is selected by the crew.
White A pitch trim actuator (secondary) fault is
detected.
Description
PM-132A