Technical data

13773-001
27-30
Page 1
ELEVATOR AND PITCH TRIM SYSTEM
1. DESCRIPTION
This section describes that portion of the flight control system which controls the position and movement of
the elevator. Included are; elevator system torque tube, rigging, push/pull rods, pulleys, and pitch trim car-
tridge.
Elevator control motion is transferred by conventional yoke motion through a linkage to a pulley sector
mounted on the elevator torque tube. From the pulley sector, the single cable system runs to a pulley gang
at the bottom of the center console, routed to a second pulley gang under the baggage floor, and finally to
the elevator actuation pulley. The elevator actuation pulley drives a push/pull rod attached to the elevator
bellcrank which is bolted directly to the elevators. Each set of pulleys has a cable retainer to prevent foul-
ing. Adjustable control stops at the elevator actuation pulley limit control surface travel.
The pitch trim system employs a ground adjustable trim tab, and a spring cartridge activated by an electric
motor to act as the autopilot servo. The spring cartridge, directly connected to the elevator bellcrank and
the electric trim motor, provides a centering force regardless of the direction of control surface deflection.
When activated, the trim motor moves the spring cartridge causing the elevator bellcrank to move the ele-
vator to a new trimmed position. A 4-way switch, mounted on both yoke grips, controls the pitch trim sys-
tem.
WARNING:
A system rigging Inspection/Check must be performed after loosening any flight con-
trol cable to assure proper control surface operation. Refer to the appropriate control
system’s rigging procedures for the Inspection/Check maintenance practices.
2. MAINTENANCE PRACTICES
A. Elevator System Rigging (See Figure 27-301)
(1) Removal - Elevator System Cable
(a) Acquire necessary tools, equipment, and supplies.
(b) Remove RH mid console trim panel. (Refer to 25-10)
(c) Remove LH mid console circuit breaker trim panel. (Refer to 25-10)
(d) Remove passenger seats. (Refer to 25-10)
(e) Remove carpet and access panels CF5. (Refer to 6-00)
(f) Remove empennage pulley gang. (Refer to 27-20)
(g) Remove cotter pin and washer securing pulley guard pin to rudder-elevator pulley gang
bracket and remove pin.
(h) Remove cotter pins and washers securing pulley guard pins to forward pulley gang bracket
and remove pins.
Note: To facilitate cable routing during installation, attach string to end of cables
prior to removing from airplane.
(i) Remove nuts, washers, and screws securing elevator cables to elevator pulley sector.
(j) At elevator pulley sector pull forward cables through. Cut string from cable and remove
cable from airplane.
Description P/N or Spec. Supplier Purpose
String - Any Source Cable Routing
30 Nov 2000