FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 4. Metal Structure, Welding, and Brazing | 5. Welding and Brazing | 4-95. Splicing Tubing by Inner-Sleeve Method
9/27/01
AC 43.13-1B CHG 1
d. Members Dented in a Bay. Repair
dented, bent, cracked, or otherwise damaged
tubular members by using a split-sleeve rein
forcement. Carefully straighten the damaged
member, and in the case of cracks, drill
No. 40 (0.098) inch stop holes at the ends of
the crack.
4-92. REPAIR BY WELDED SLEEVE.
This repair is outlined in figure 4-35. Select a
length of steel tube sleeve having an inside di
ameter approximately equal to the outside di
ameter of the damaged tube and of the same
material, and at least the same wall thickness.
Diagonally cut the sleeve reinforcement at a
30-degree angle on both ends so that the
minimum distance of the sleeve from the edge
of the crack or dent is not less than 1-1/2 times
the diameter of the damaged tube. Cut through
the entire length of the reinforcement sleeve,
and separate the half-sections of the sleeve.
Clamp the two sleeve sections to the proper
positions on the affected areas of the original
tube. Weld the reinforcement sleeve along the
length of the two sides, and weld both ends of
the sleeve to the damaged tube. (See fig
ure 4-35.) The filling of dents or cracks with
welding rod in lieu of reinforcing the member
is not acceptable.
4-93. REPAIR BY BOLTED SLEEVE.
Do not use bolted-sleeve repairs on welded
steel-tube structure unless specifically author
ized by the manufacturer or the FAA. The
tube area removed by the bolt holes, in this
type of repair, may prove critical.
4-94. WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a
patch of the same material, one gauge thicker.
(See figure 4-36.)
a. Dented Tubing.
(1) Dents are not deeper than 1/10 of
tube diameter, do not involve more than 1/4 of
the tube circumference, and are not longer than
tube diameter.
(2) Dents are free from cracks, abrasions,
and sharp corners.
(3) The dented tubing can be substantially re
formed, without cracking, before application
of the patch.
b. Punctured Tubing. Holes are not longer
than tube diameter and involve not more than
1/4 of tube circumference.
4-95. SPLICING TUBING BY INNER
SLEEVE METHOD. If the damage to a
structural tube is such that a partial replace
ment of the tube is necessary, the inner-sleeve
splice is recommended; especially where a
smooth tube surface is desired. (See fig
ure 4-37.)
a. Make a diagonal cut when removing the
damaged portion of the tube, and remove the
burr from the edges of the cut by filing or
similar means. Diagonally cut a replacement
steel tube of the same material and diameter,
and at least the same wall thickness, to match
the length of the removed portion of the dam
aged tube. At each end of the replacement
tube allow a 1/8-inch gap from the diagonal
cuts to the stubs of the original tube. Select a
length of steel tubing of the same material, and
at least the same wall thickness, and of an out
side diameter equal to the inside diameter of
the damaged tube. Fit this inner-sleeve tube
material snugly within the original tube, with a
maximum diameter difference of 1/16 inch.
From this inner-sleeve tube material cut two
sections of tubing, each of such a length that
the ends of the inner sleeve will be a minimum
distance of 1-1/2-tube diameters from the
nearest end of the diagonal cut.
Par 4-91
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