Flight Control System Description And Operation; Flight Control System - Standard Procedures - Piper PA-44-180 SEMINOLE Maintenance Manual

GENERAL.
DESCRIPTION AND OPERATION.
The airplane is controlled in flight by the use of three primary control surfaces, consisting of ailerons,
s t abilator and rudder. Operation of these controls is through the movement of the control column-tee bar
assembly and rudder pedals. On the forward end of each control column is a sprocket assembly. A chain is
wrapped around the sprockets to connect the right and left controls and then back to idler sprockets on the
columns' tee bar, which in turn connect to the aileron primary control cables. The cables operate the aileron
bellcrank and push-pull rods. The stabilator is controlled by a cable connected to the bottom of the tee bar
assembly and operates an aft fuselage bellcrank which controls a push rod connected to the balance arm of the
stabilator. Cables also connect the rudder pedals with the rudder sector.
Provisions for directional and longitudinal trim control is provided by an adjustable trim mechanism for
the stabilator and rudder. The stabilator trim is controlled by a wheel and drum mounted on the floor tunnel
between the front seats. Cables routed aft from the drum to a screw assembly mounted above the stabilator
attachment point. This screw assembly in turn moves the push rod which controls the stabilator trim tab. The
rudder trim is controlled by a trim wheel behind the flap control lever. Cables for the rudder trim are routed
back through the fuselage and up into the tail where they attach to their aft actuator drum. The rudder tab is
then driven by a push rod assembly connected to the actuator drum.
STANDARD PROCEDURES.
The following tips may be helpful where applicable in the individual control system procedures.
1 . Turnbuckles must be assembled and adjusted in a manner that each terminal end is screwed an
a p p r o ximately equal distance into the barrel. During adjustment, the terminals must not be turned in a
manner which would put a permanent twist in the cable.
2. After adjustment is completed, each turnbuckle must be checked. Not more than three terminal
threads shall be visible outside the barrel. Locking clips must be installed and checked for proper
installation by trying to remove the clips using fingers only. Locking clips which have been installed
and removed must be scrapped and new clips used.
3. Torque all nuts in the flight control surface rigging system in accordance with AC 43.13-1A or to
torques specified within this manual text.
4. After completion of adjustment, each jam nut must be tightened securely and inspected.
5. On push rods or rod ends provided with an inspection hole, screws must be screwed in far enough to
pass the hole. This can be determined visually or feel, by inserting a piece of wire into the inspection
hole. If no inspection hole is provided, a minimum of 0.375 of an inch thread engagement must be
maintained.
6 . All cable rigging tensions given must be corrected to ambient temperature in the area where the tension
is being checked by using Chart 2701.
7. See Figure 27-1 for the proper method of adjusting rod ends to prevent possible damage and binding
of bearing surface in rod end.
IF THE FLAPS AND AILERONS ARE BOTH DISCONNECTED FROM
THE CONTROL SYSTEM, AND LEFT TO HANG ON THEIR HINGES, BE
CAREFUL IN LETTING ONE ROTATE DOWN AFTER HAV I N G
RELEASED THE OTHER, AS THEY WILL "LOCK-UP" AND DAMAGE
THEIR SKINS.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
1K3
27-00-00
Page 27-1
Revised: June 20, 1995