Cessna 150M - Wing Stringers; Wing Auxiliary Spars; Wing Ribs; Wing Spars

are not used, make an overlapping type of repair.
Where optimum appearance and airflow are desired,
the flush patch may be used. Careful workmanship
will eliminate gaps at butt-joints; however, an epoxy
type filler may be used at such joints.
18-15. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If a skin is badly damaged, repair must
be made by replacing an entire skin panel, from one
structural member to the next. Repair seams must
be made to lie along existing structural members
and each seam must be made exactly the same in re-
gard to rivet size, spacing, and pattern as the manu-
factured seams at the edges of the original sheet. If
the manufactured seams are different, the stronger
must be copied. If the. repair ends at a structural
member where no seartJ. is used, enough repair panel
must be used to allow an extra row of staggered
rivets, with sufficient edge margin, to be installed.
18-16. WING STRINGERS.
18-17. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-18.
REPAIRABLE DAMAGE. Figure 18- 5 out-
lines a typical wing stringer repair. Two such re-
pairs may be used to splice a new section of stringer
material in position, without the filler material.
18-19. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If a stringer is so badly damaged that
more than one section must be spliced, replacement
is recommended.
18-20. WING AUXILIARY SPARS.
18-21. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-22. REPAIRABLE DAMAGE. Figure 18-8 illus-
trates a typical auxiliary spar repair.
18-23. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If damage to an auxiliary spar would
require a repair which could not be made between ad-
jacent ribs, the auxiliary spar must be replaced.
18-24. WING RIBS.
18-25. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-26. REPAIRABLE DAMAGE. Figure 18-6 illus-
trates a typical wing rib repair.
18-27. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. Leading and trailing edge ribs that are
extensively damaged can be replaced. However, due
to the necessity of unfastening an excessive amount of
skin in order to replace the rib, they should be re-
paired if practicable. Center ribs, between the front
and rear spar should always be repaired if practicable.
18-28. WING SPARS.
18-29. NEGLIGIBLE DAMAGE. Due to the stress
which wing spars encounter, very little damage can
be considered negligible. All cracks, stress wrink-
les, deep scratches, and sharp dents must be re-
paired. Smooth dents, light scratches and abrasions
may be considered negligible.
18-30. REPAIRABLE DAMAGE. Figure 18-7 illus-
trates typical spar repairs. It is often practical to
cut repair pieces from service parts listed in the
Parts Catalog. Service Kits are available for certain
types of spar repairs.
18-31. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. Damage so extensive that repair is not
practicable requires replacement of a complete wing
spar. Also refer to paragraph 18-2.
18-32. AILERONS.
18-33. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-34. REPAIRABLE DAMAGE. Figure 18-3A may
be used as a guide to repair damage to aileron skins.
It is recommended that all material used for the re-
pair be cut from spare parts of the same guage and
corrugation spacing. Repair should extend from the
leading edge to the trailing edge. Following the re-
pair, the aileron must be balanced. Refer to par-
agraph 18-36 and figure 18-3A for balancing. If
damage would require a repair which could not be
made between adjacent ribs, refer to paragraph
18-35.
18-35.
DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If the damage would require a repair
which could not be made between adjacent ribs, com-
plete skin panels must be replaced. Ribs and spars
may be repaired, but replacement is generally pre-
ferable. Where extensive damage has occured, re-
placement of the aileron assembly is recommended.
After repair and/or replacement, balance aileron
in accordance with paragraph 18-36 and figure 18-3.
18-36. AILERON BALANCING. Following repair,
replacement or painting, the aileron must be balanced.
Complete instructions for fabricating balancing fix-
tures and mandrels and their use are given in figure
18-3.
18-37. WING FLAPS.
18-38. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-39.
REPAIRABLE DAMAGE. Flap repairs should
be Similar to aileron repairs discussed in paragraph
18-34. A flap leading edge repair is shown in figure
18-10.
18-40. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. Flap repairs which require replacement
of parts should be similar to aileron repairs dis-
cussed in paragraph 18-35. Since the flap is not con-
sidered a moveable control surface, no balancing is
required.
18-3