Diamond DA 42 NG, Maintenance Manual

Page: 903 / 2339

AIRCRAFT
DA 42 NG AMM Flight Controls
Doc # 7.02.15
Rev. 4
27-39-00
Page 1
15 Mar 2018
Section 27-39
Flight Controls - Elevator Trim-Electrical
1. General
This Section tells you about the elevator electrically controlled trim system. Refer to Section 27-38 for
data about the elevator mechanical trim control system.
A thumb switch on the pilot’s control stick operates the DA 42 NG electrically controlled elevator trim
system.
2. Description
The DA 42 NG elevator has a trim tab that can be operated mechanically via the usual trim wheel in
the center console or electrically via a trim switch on the pilot’s control stick. The elevator electrical trim
system is integrated with the autopilot control system. For more data about the autopilot control system
and the interaction with the elevator electrical trim system refer to Chapter 22.
The elevator electric trim system has two main components:
A. Pilot’s Control Stick Switch
A thumb switch on the pilot’s control stick operates the elevator electrical trim servo. The switch is
spring loaded at the neutral position. The switch can pushed against the spring in a forward or aft
direction. When pushed forwards the trim servo will trim the airplane more nose down and when
pushed aft the trim servo will trim the airplane more tail heavy.
B. Elevator Trim Servo
The DA 42 NG has a pitch trim servo located below the co-pilot’s seat. The servo is mounted on
an aluminum plate and is attached to the plate with a GFRP bracket. A chain gear on the servo,
a cardan shaft and a chain gear on the right side of the cockpit trim wheel transmits the movement
of the servo to the elevator trim wheel.
When the pilot operates the electric trim switch on the control stick the servo will operate and drive
the mechanical trim wheel to the required position.