Diamond DA 42 NG, Maintenance Manual

Page: 859 / 2339

AIRCRAFT
DA 42 NG AMM Flight Controls
Doc # 7.02.15
Rev. 4
27-30-00
Page 3
15 Mar 2018
2. Description
Figure 1 shows the elevator controls in the cockpit. Figure 2 shows the elevator controls in the rear
fuselage.
Each pilot has a control stick that attaches to the torque tube assembly. The torque tube assembly has
a lever which attaches to a short pushrod. The short pushrod connects to an idler lever on the front
main bulkhead. The idler lever connects to a long pushrod.
The long pushrod has three guide bearings. The aft baggage frame, ring frame 1 and ring frame 2
have pushrod guides. Each guide has three rollers.
The long pushrod attaches to a bellcrank at the bottom of the vertical stabilizer. The bellcrank attaches
to a vertical pushrod in the vertical stabilizer. The vertical pushrod connects to the elevator horn. The
vertical pushrod has two balance springs attached to a bracket welded to the pushrod. These springs
assist the elevator to return to the neural position.
The elevator stop for the downward movement consists of a GFRP block which is bonded to the inside
of the upper skin of the horizontal stabilizer. When the elevator is deflected fully downwards, the
forward extension of the elevator horn is deflected fully upwards and contacts the stop.
The elevator stop for the upward movement consists of a bolt/bush assembly which is installed in the
trim actuator mounting bracket in a transverse direction (refer to Section 27-38). When the elevator
is deflected fully upwards, the forward extension of the elevator horn is deflected fully downward and
contacts the stop.
Figure 3 shows the variable elevator stop. The DA 42 NG is equipped with an electrically operated
actuator that limits the elevator up travel to 13° as soon as the power setting of both engines exceeds
approximately 20 %. The linear actuator acts as a movable stop and is controlled by two switches on
the throttle quadrant, one for each power lever. When power is reduced below approximately 20 %,
full elevator deflection is regained. The operation of the variable elevator stop is only controlled by the
position of the engine power levers and cannot be selected or deselected by the pilot.
An amber STICK LIMIT caution is provided on the PFD to inform the pilot in case a malfunction is
present. The STICK LIMIT caution appears when the variable elevator stop should be in place and is
actually not activated (power ON condition) or should be retracted and actually limits the elevator travel
(power OFF condition). The annunciation circuitry is not operative when one power lever is positioned
beyond the approach power setting, while the other is below or in idle position (engine failure or
training).
You cannot adjust the elevator stops.