Diamond DA 42 NG, Maintenance Manual

Page: 1685 / 2339

AIRCRAFT
DA 42 NG AMM
Standard
Practices/Structures
Doc # 7.02.15
Rev. 4
51-60-00
Page 1
15 Mar 2018
Section 51-60
Control Surface Balancing
1. General
This Section tells you how to weigh and measure the residual moment of the control surfaces. Figure 1
thru 4 show typical Weights and Residual Moments Reports for the DA 42 NG airplane.
WARNING: YOU MUST WEIGH AND CHECK THE BALANCE OF A CONTROL
SURFACE AFTER ANY WORK WHICH COULD AFFECT ITS WEIGHT
OR ITS BALANCE. AN OUT OF BALANCE CONTROL SURFACE CAN
FLUTTER AND CAUSE STRUCTURAL FAILURE.
Correct control surface balance is critical to flight safety. You must remove a control surface to weigh
it and check its balance after:
)
Any repair to the control surface.
)
Painting the control surface.
)
Any report of control vibration or flutter in flight.
You can use any convenient method to weigh a control surface. If you use anything to connect the
control surface to the weighing device then you must weigh the device, (for example, a sling)
separately and deduct its weight from the total value. For example, you use a rope sling to weigh an
aileron with a spring balance:
)
Weight of aileron and the rope sling = 3.8 kg (8.378 lb).
)
Weight of rope sling = 0.7 kg (1.543 lb).
)
Weight of aileron = (3.8 kg - 0.7 kg) = 3.1 kg (6.835 lb).
When you do a test for the correct balance of a control surface, the pivot angle of the control must be
as shown in the Weights and Residual Moments Report.
We recommend that for balancing the flaps, aileron, elevator and elevator trim tab, you put a suitable
size rod through the hinge bearings. Support the rod at two points to keep it horizontal.
To balance the rudder it must be supported at the top pivot pin and the bottom mounting bracket. The
center line of the rudder must be horizontal.