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 | 4-102. Landing Gear Repair
9/27/01
AC 43.13-1B CHG 1
d. If all members are out of alignment, re
ject the engine mount and replace with one
supplied by the manufacturer or one which was
built to conform to the manufacturer’s draw
ings. The method of checking the alignment
of the fuselage or nacelle points should be re
quested from the manufacturer.
e. Repair minor damage, such as a crack
adjacent to an engine-attachment lug, by rew
elding the ring and extending a gusset or a
mounting lug past the damaged area. Engine-
mount rings which are extensively damaged
must not be repaired, unless the method of re
pair is specifically approved by the FAA, or
the repair is accomplished in accordance with
FAA-approved instructions.
f. If the manufacturer stress relieved the
engine mount after welding it, the engine
mount should be re-stress relieved after the
weld repairs are made.
4-100. BUILT-UP TUBULAR WING OR
TAIL-SPARS. Repair built-up tubular wing
or tail-spars by using any of the applicable
splices and methods of repair shown in fig
ure 4-35 through figure 4-45, provided the
spars are not heat treated. In the case of heat-
treated spars, the entire spar assembly would
have to be reheat treated to the manufacturer’s
specifications after completion of the repair.
In general, this will be found less practicable
than replacing the spar with one furnished by
the manufacturer or holder of the PMA for the
part.
4-101. WING-BRACE STRUTS AND
TAIL-BRACE STRUTS. In general, it will
be found advantageous to replace damaged
wing-brace struts made either from rounded or
streamlined tubing with new members pur
chased from the original manufacturer. How
ever, there is no objection, from an airworthi
ness point of view, to repairing such members
in a proper manner. An acceptable method of
repair, if streamlined tubing is used, will be
found in figure 4-43. Repair similar members
made of round tubes using a standard splice, as
shown in figure 4-35, figure 4-37, or fig
ure 4-38.
a. Location of Splices. Steel-brace struts
may be spliced at any point along the length of
the strut provided the splice does not overlap
part of an end fitting. The jury-strut attach
ment is not considered an end fitting; there
fore, a splice may be made at this point. The
repair procedure and workmanship minimize
distortion due to welding and the necessity for
subsequent straightening operations. Observe
every repaired strut carefully during initial
flights to ascertain that the vibration charac
teristics of the strut and attaching components
are not adversely affected by the repair. A
wide range of speed and engine-power combi
nation must be covered during this check.
b. Fit and Alignment. When making re
pairs to wing and tail surface brace members,
ensure to proper fit and alignment to avoid
distortion.
4-102. LANDING GEAR REPAIR.
a. Round Tube Construction. Repair
landing gears made of round tubing using
standard repairs and splices as shown in fig
ure 4-35 and figure 4-41.
b. Streamline Tube Construction. Repair
landing gears made of streamlined tubing by
either one of the methods shown in fig
ure 4-42, figure 4-44, or figure 4-45.
c. Axle Assemblies. Representative types of
repairable and nonrepairable landing gear axle
assemblies are shown in figures 4-46 and 4-47.
The types as shown in A, B, and C of this fig
ure are formed from steel tubing and may be
repaired by the applicable method
Par 4-99
Page 4-73