Cessna T303 Installation, Service & Parts Manual page 277

Avionic Installations Service/Parts Manual
Elevator Friction Band Check. The desired elevator
friction band without an autopilot installed is 10
pounds or less. The maximum allowable friction
band is 12 pounds with an autopilot installed. The
friction band shall be cnecked every time the auto-
pilot rigging is checked. The friction band shall be
measured and calculated in accordance with Steps 1
and 2.
Corrective action to reduce the aileron sys-
tem friction band shall be accomplished in accord-
ance with Step 3.
Step 1. Friction Band Measurements - All
friction band measurements shall be made with the
load scale so situated that the force exerted to move
the elevator is applied in a direction parallel to the
control column. The resulting movement of the con-
trol wheel assembly shall be slow and steady. The
friction band requirements apply over the complete
elevator travel range. The production inspection
shall be made at or within one inch either side of
the position occupied by the control wheel assembly
when the elevator is in neutral position.
A.
Starting with the elevators in a down posi-
tion (control wheel assembly one inch forward of the
position occupied when elevator is in neutral posi-
tion), move the control wheel assembly aft by exert-
ing force as above. Take load scale reading as
wheel assembly passes the elevator neutral position.
Identify this reading as F1.
B.
Starting with the elevators in an up position
(control wheel assembly one inch aft of the position
occupied when elevator is in neutral position), move
the control wheel assembly forward by exerting
force as above. Take load scale reading as wheel
assembly passes the elevator neutral position.
Identify this reading as F
2
.
Step 2. Friction Band Calculation - The eleva-
tor friction band shall be calculated from the mea-
surements taken in Step 2, as follows:
A.
In a system where a force must be exerted
in a direction toward the panel (forward) to return
the elevators to a down position, the friction band is
the sum of forces F
1
and F
2
.
Friction Band
-
F
1
+ F
2
B. In a system where a restraining force must
be exerted in a direction away from the panel (aft) to
prevent the elevator from abruptly returning to a
down position, the firction band is the difference of
the two forces.
Friction Band - F
1
- F
2
Step 3. Corrective Action - When the friction
band exceeds limits specified in Step 1, the following
steps shall be taken as required, in order shown, to
reduce the system friction.
A. Reduce elevator cable tension as required
(11 pounds minimum without an autopilot installed or
12 pounds minimum with an autopilot installed) with
the elevator in neutral position.
B.
Apply a thin film of lubricant to outer sur-
face of round outer control tube. *
C. 1. Apply lubricant to:*
a. Inner surface of round outer con-
trol tube in glide contact area.
b. Contact surface of glide on end of
inner square control tube.
2. Check adjustment of glide.
Loosen
only as required to ensure free move-
ment over full travel range.
*(Recommended lubricant - SIL-GLYDE,
American Grease Stick Company, Muskegon
Michigan)
D. Check for binding and alignment of pulley
and correct as necessary.
Electric Trim Rigging. To checkout the electric
trim rigging, proceed as follows:
NOTE
Before proceeding with the following proce-
dures, be sure the elevator control system
has been rigged in accordance with the pro-
ceeding elevator rigging instructions and
that the manual electric trim system has
been rigged in accordance with the basic
airplane's Service Manual for cable tensions,
travels and friction.
Step 1.
Place control wheels in neutral position
of elevator, and secure control wheels in neutral po-
sition by using the control column neutral rigging
tool shown in the previous Elevator Rigging proce-
dures and referred to in Step 1 of those procedures.
Step 2. (Refer to Illustration F.) Remove the
two access plates (2 & 22) on the top side of the
right-hand stabilizer to gain access to the electric
trim actuator (25) and trim tab actuator assembly
(9).
Step 3.
Ensure that the electric trim actuator
assembly (25) is securely attached to the base as-
sembly (26) with four washers (28) and screws (29).
Remove the outboard access plate on the underside
of the stabilizer and ensure that the base assembly
(26) is securely attached to the two stiffeners (27 &
30) with four screws (31).
Figure 7-1.
Rigging Procedures for Cessna 400B and 400B IFCS (Types AF-550A & IF-550A) (Sheet 9 of 14)
7-10