A prelight check of the switches should be accomplished before light by moving the switches individually on both
control wheels. No one switch alone should operate the system; operation of elevator trim should occur only by
movement of pairs of switches. The trim system disconnect is a bi-level pushbutton, momentary type switch, located
on the outboard grip of each control wheel. Depressing the switch to the irst of two levels disconnects the autopilot
and yaw damp system, and the second level disconnects the electric trim system. The system can be reset by
moving the ELEV TRIM switch toggle on the pedestal (Fig. 2-19) to OFF/RESET position, then back to ELEV TRIM
c. Aileron Trim Tab Control. The aileron trim tab control, placarded AILERON TAB LEFT , RIGHT , located
in the control pedestal (Fig. 2-19), adjusts the aileron trim tab. The amount of aileron tab delection from a neutral
setting, as indicted by a position indicator, is relative only and is not in degrees.
d. Rudder Trim Tab Control. The rudder trim tab control knob, placarded RUDDER TAB LEFT, RIGHT , located
in the control pedestal (Fig. 2-19), controls adjustment of the rudder trim tab. A position indicator indicates the
amount of rudder tab delection, in units from a neutral setting.
2-40. WING FLAPS.
The slot-type wing laps are electrically operated and consist of two sections for each wing. These sections extend
from the inboard end of each aileron to the junction of the wing and fuselage. During extension, or retraction, the
laps are operated as a single unit, each section being actuated by a separate jackscrew actuator. The actuators
are driven through lexible shafts by a single reversible electric motor. Wing lap position is indicated in percent of
travel by a lap position indicator on the center subpanel. Full lap extension and retraction time is approximately 11
seconds. The lap control switch is located in the control pedestal. No emergency wing lap actuation system is pro-
vided. With laps extended beyond the APPROACH position, the landing gear warning horn will sound, unless the
landing gear is down and locked. The circuit is protected by a 20-ampere circuit breaker, placarded FLAP MOTOR
, located on the overhead circuit breaker panel (Fig. 2-12).
a. Wing Flap Control Switch. A three-position switch with a lap shaped handle on the control pedestal (Fig.
2-19) controls lap operation. The handle of this switch is placarded FLAP . Switch positions are placarded: FLAP
UP , APPROACH and DOWN . The amount of extension of the laps is established by position of the lap switch
as follows: UP = 0%, APPROACH = 40%, and DOWN = 100%. Limit switches, mounted on the right inboard lap,
establish the lap travel. The lap control switch, limit switch, and relay circuits are protected by a 5-ampere circuit
breaker, placarded FLAP CONTR located on the overhead circuit breaker panel (Fig. 2-12). Intermediate lap posi-
tions between UP and APPROACH cannot be selected. For intermediate lap positions between APPROACH and
DOWN , the APPROACH position acts as an off position. To return the laps to any position between full DOWN
and APPROACH place the lap switch to UP and when desired lap position is obtained, return the switch to AP-
PROACH detent. To return the laps to full UP , place the lap switch to the UP detent position. To return the laps to
APPROACH , move the lap switch to the UP position and then to the APPROACH detent position. In the event that
any two adjacent lap sections extend 3 to 5 degrees out of phase with the other, a safety mechanism is provided to
discontinue power to the lap motor.
b. Wing Flap Position Indicator. Flap position in percent of travel from O percent (UP ) to 100 percent (DOWN
) is shown on an indicator, placarded FLAPS , located in the center subpanel (Fig. 2-11). The approach and full
down lap positions are 14 and 35 degrees, respectively. The lap position indicator is protected by the 5-ampere
circuit breaker, placarded FLAP CONTR , located on the overhead circuit breaker panel (Fig. 2-12).