Zlin Aviation
Section 2
Maintenance Manual Line Maintenance, Repairs and Alterations
Issued: 01/02/2006
QAP-AMM-Rev02
Date of latest Revision: 23/01/2013
Page Number: 2-6
CABLE SYSTEM INSPECTION
Aircraft cable systems are subject to a variety of environmental conditions and deterioration.
Wire or strand breakage is easy to visually recognize. Other kinds of deterioration such as
wear, corrosion, and/or distortion are not easily seen; therefore, control cables should be removed
periodically for a more detailed inspection.
All control cables must be inspected
DAILY
for broken wires strands. Any cable assembly that
has one broken wire strand located in a critical fatigue area must be replaced.
A critical fatigue area
is defined as the working length of a cable where the cable runs over, under,
or around a pulley, sleeve, or through a fair-lead; or any section where the cable is flexed, rubbed,
or worked in any manner; or any point within 1 foot of a swaged-on fitting.
Close inspection in these critical fatigue areas,
must be made by passing a cloth over the area to snag on broken wires. This will clean the cable for
a visual inspection, and detect broken wires if the cloth
snags on the cable. Also, a very careful visual
inspection must be made since a broken wire will not
always protrude or stick out, but may lie in the strand
and remain in the position of the helix as it was
manufactured. Broken wires of this type may show up
as a hairline crack in the
wire. If a broken wire of this type is suspected, further
inspection with a magnifying glass of 7 power or
greater, is recommended. Figure shows a cable with
broken wires that was not detected by wiping, but was
found during a visual inspection. The damage became readily apparent when the cable was removed
and bent as shown in figure.
Examine cable runs
for incorrect routing, fraying, twisting, or wear at fair-leads, pulleys,
antiabrasion strips, and guards. Look for interference with adjacent structure, equipment, wiring,
plumbing, and other controls. Inspect cable systems for binding, full travel, and security of
attaching hardware. Check for slack in the cable system by attempting to move the control column
and/or pedals while the gust locks are installed on the control surfaces. With the gust locks
removed, actuate the controls and check for friction or hard movement. These are indications that
excessive cable tension exists.
Inspect pulleys
for roughness, sharp edges, and presence of foreign material embedded in the
grooves. Examine pulley bearings to ensure proper lubrication, smooth rotation; and freedom from
flat spots, dirt, and paint spray. During the inspection, rotate the pulleys, which only turn through a
small arc, to provide a new bearing surface for the cable. Maintain pulley alignment to prevent the
cable from riding on the flanges and chafing against guards, covers, or adjacent structure. Check
all pulley brackets and guards for damage, alignment, and security.