FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 2. Fabric Covering | 1. Practices and Precautions | 2-6. Preparation of the Structure for Covering
AC 43.13-1B
9/8/98
TABLE 2-2. Cotton and Linen, Tapes and Threads.
Materials
Minimum
Specification Yarn Size Tensile Strength
Yards Per
Pound
Reinforcing
tape, cotton.
MIL-T-566 1 E,
Type 1
MIL-Y-1140H
Lacing cord,
prewaxed Federal T-C-57
braided cotton.
1F
Lacing cord,
braided cotton. MIL-C-5648A
150 pounds per
1/2 inch width.
40 pounds. 310 minimum.
80 pounds. 170 minimum.
Lacing cord
thread, high
tenacity cotton.
MIL-T-5660B
Machine
thread cotton
Federal V-T-
276H
Hand-Sewing Federal V-T-
thread cotton. 276H Type III B
Finishing
(Surface) tape Same as fabric
cotton.
used.
Ticket No.
10.
20/4 ply
8/4 ply
62 pounds.
5 pounds.
14 pounds.
Same as fabric
used.
480 minimum.
5,000 nominal.
1,650 nominal.
Use and Remarks
Used as reinforcing tape on fabric and
under rib lacing cord. Strength of other
widths approx. in proportion.
Lacing fabric to structures. Unless
already waxed, must be lightly waxed
before using.
Lacing fabric to structures. Unless
already waxed, must be lightly waxed
before using.
Lacing fabric to structures. Unless
already waxed, must be lightly waxed
before using.
Use for all machine sewing.
Use for all hand-sewing.
Use fully waxed thread.
Use over seams, leading edges, trailing
edges, outer edges and ribs, pinked,
raveled or straight edges.
c. Fairing Precautions. Aluminum
leading edge replacement fairings installed in
short sections may telescope during normal
spar bending loads or from thermal expansion
and contraction. This action may cause a
wrinkle to form in the fabric, at the edge of the
lap joint. Leading edge fairing sections may
be fastened together with rivets or screws to
prevent telescoping after installation. Trailing
edges should be adequately secured to prevent
movement and wrinkles.
d. Dope Protection. Solvents found in
nitrate and butyrate dope will penetrate, wrin
kle, lift, or dissolve most one-part wood var
nishes and one-part metal primers. All wood
surfaces that come in contact with doped fabric
should be treated with a protective coating
such as aluminum foil, cellulose tape, or dope-
proof paint to protect them against the action
of the solvents in the dope. This can also be
accomplished by recoating with a suitable,
solvent resistant two-part epoxy varnish, which
will be impervious to solvent penetration and
damage after curing. Clad aluminum
and stainless steel parts need not be dope-
proofed.
(1) A solvent-sensitive primer on fer
rous metal and aluminum alloy components
which will be in contact with fabric may be
protected from solvent damage by overcoating
with a two-part epoxy primer. Epoxy primer
meeting MIL-P-53022B is acceptable.
(2) Small metal or wood surfaces, such
as rib caps, to which fabric will not be dope
bonded as a part of the particular fabric at
tachment procedure may be protected from
dope damage by cellophane tape or aluminum
foil.
e. Chafe Protection. Fabric and finishing
tape is often cut through with sandpaper over
sharp edges during the coating and finishing
procedure and later polishing. All sharp metal
edges or protruding screws, nails, rivets, and
bolt heads should be covered with an anti-
chafe tape to prevent cutting and wearing
through the fabric after installation. Use
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