adjoining surfaces. Replace the hinge bolts in the
the general precautions listed under "Removal and
hinges to prevent them from being lost or damaged.
Installation of Wings" also apply to stabilizer removal
and installation.
Before installing a control surface, check the
identification tag to determine its proper location on
FLIGHT CONTROL SURFACES
the aircraft. Place the surface in position carefully. You
should ensure that all the hinge holes are properly
It is sometimes necessary to remove control
aligned. Drift pins may be used to align the holes. With
surfaces from aircraft to repair or replace them. The
the control surface correctly supported, install the
instructions presented in the following paragraphs are
hinge bolts. For a surface attached by piano hinge wire,
general instructions, applicable to several types of
a new wire should be used. After a control surface is
aircraft. For specific instructions and precautions, you
installed, connect the control linkage and check the
should always consult the MIM before removing a
rigging of the system.
control surface from any aircraft.
Q16-57. W h o m u s t s u p e r v i s e t h e re m o v a l a n d
Removal of a control surface should not be
installation of a wing assembly?
attempted until the aircraft is placed in a hangar or an
Q16-58. What is the first step the person in charge must
area protected from the wind. Before any control
p e r f o r m b e f o re i n s t a l l i n g a n ew w i n g
surface is removed from the aircraft, it should be
assembly?
tagged with the bureau number of the aircraft and the
Q16-59. Many of the general precautions listed under
location of the control surface on the aircraft.
t h e re m o v a l a n d i n s t a l l a t i o n o f w h a t
The first step is to remove the access covers and
c o m p o n e n t a p p l y t o t h e re m o v a l a n d
fairings. To prevent the loss of these parts, they should
replacement of a stabilizer?
be left attached to the aircraft by one screw or by a
Q16-60. What tool is used for removing the piano wire
piece of safety wire. The other screws should be put in
of a flight control surface?
a container to prevent them from being lost.
Q16-61. When installing a flight control surface, what
Disconnect bonding wires, electrical connectors,
tool is used to ensure that the hinge holes are
and control linkage. Before disconnecting cable
properly aligned?
linkage, you should relieve the tension at the most
convenient turnbuckle. Next, support the entire control
AIRFRAME AND CONTROL SURFACE
surface, either manually or with mechanical supports,
ALIGNMENT
in such a manner as to remove all the load from the
hinges. Remove the hinge bolts by using a mallet and
LEARNING OBJECTIVE: Identify the
brass pin. The control surface should be supported and
methods used to balance flight control
all the hinges kept in alignment until the last hinge bolt
surfaces and airframe/control surface
has been removed. On long control surfaces, it may be
alignment checks.
necessary to replace the hinge bolts with drift pins to
keep the hinges aligned while removing the remaining
Alignment of the airframe structure means
checking the position relationship of each major
hinge bolts.
component--the wing group, tail group, and fuselage
Control surfaces are sometimes attached with
group--to the other. The alignment of the airframe is
piano wire hinges. Removal of the piano wire can be
important since it is directly related to the aerodynamic
accomplished by removing the ends, securing one end
performance of the aircraft. Misalignment may affect
of the wire in the chuck of a hand drill, and rotating the
the flight characteristics of the aircraft, and
wire with the drill while withdrawing it. Excessive
consequently, the efficiency of the pilot-aircraft
spinning will have a wearing effect on the hinge
combination.
material and should be avoided. The reuse of piano
For this reason and for purposes of determining if
hinge wire is not safe; therefore, any wire removed
any hidden structural failures exist, an alignment check
should be discarded.
should be performed when an aircraft has encountered
After all the hinges are disconnected, remove the
excessive g's in flight, when a hard landing has been
control surface from the aircraft and support it
experienced, or when the aircraft has been subjected to
carefully to prevent damage to the hinge brackets and
extensive damage.
16-51
