Cessna 188 Series Service Manual page 373

MODEL 188 & T188 SERIES SERVICE MANUAL
17-52. REPAIRABLE DAMAGE.
Skin patches shown 17-57. REPAIRABLE DAMAGE.
Fuselage skin re-
in figure 17-4 may be used to repair skin damage.
pairs may be accomplished in the same manner as
Access to the dorsal area of the fin may be gained by wing skin repairs outlined in paragraph 17-16.
removing the horizontal closing rib at the bottom of
Stringers, formed skin flanges, bulkhead channels,
the fin. Access to the internal fin structure is best
and similar parts may be repaired as shown in
gained by removing skin attaching rivets on one side figure 17-5.
of the rear spar and ribs, and springing back the
skin. Access to the stabilizer structure may be
17-58. DAMAGE NECESSITATING REPLACEMENT
gained by removing skin attaching rivets on one side OF PARTS. Fuselage skin major repairs may be
of the rear spar and ribs, and springing back the accomplished in the same manner as the wing re-
skin. If the damaged area would require a repair pairs outlined in paragraph 17-17. Damaged fittings
which could not be made between adjacent ribs, or
should be replaced.
a repair would be located in an area with compound
curves, see the following paragraph.
17-59. FIREWALL DAMAGE may be repaired by
17-53. DAMAGE NECESSITATING REPLACEMENT
removing the damaged material and splicing in a
OF PARTS. If the damaged area would require a
new section of material. The new portion should
patch which would not be made between adjacent ribs, be lapped over the old material, sealed with Pro-
or the repair would be located in an area with com-
Seal #700 (Coast Pro-Seal Co., Chemical Division,
pound curves, complete skin panels should be re-
2235 Beverly Blvd Los Angeles, California), com-
placed. Ribs and spars may be repaired, but re- pound or equivalent, and secured with stainless
placement is generally preferable. Where damage steel rivets. Damaged or deformed angles and
is extensive, replacement of the entire assembly is stiffeners may be repaired as shown in figure 17-10,
recommended.
or they may be replaced. A severely damaged fire-
wall should be replaced as a unit. Seal around all
17-54. FUSELAGE. (Except tubular structure.)
holes and openings in firewall with Pro-Seal #700
compound or equivalent.
17-55. The fuselage tallcone is of semimonocoque
17-60. ENGINE COWLING
construction, consisting of formed bulkheads, longi-
tudinal stringers, reinforcing channels, and skin
17-61. REPAIR OF COWLING SKINS. If extensively
platings. The fuselage skins and supporting struc-
damaged, complete sections of colwing should be re-
tures which surround the tubular structure, from the
placed. Standard insert-type skin patches, however,
tailcone to the firewall, are not stress members but
may be used If repair parts are formed to fit. Small
are essentially just covering. The tubular structure
cracks may be stop-drilled and dents straightened
Is discussed later in this section.
if they are reinforced on the inner side with a doubler
of the same material.
17-56. NEGLIGIBLE DAMAGE. Refer to paragraph
17- 15. Mild corrosion appearing upon alclad surfaces
17-62. REPAIR OF REINFORCEMENT ANGLES
does not necessarily indicate incipient failure of the
Cowl reinforcement angles, if damaged, should be
base metal.
However, corrosion of all types should
replaced. Due to their small size they are easier
be carefully considered, and approved remedial ac-
to replace than to repair.
tion taken.
Small cans appear in the skin structure
of all metal airplanes. It is strongly recommended,
17-63. BONDED FORWARD ACCESS DOORS.
however, that wrinkles which appear to have origin-
ated from other sources, or which do not follow the
17-64. REPAIRABLE DAMAGE. Bonded doors may
general appearance of the remainder of the skin
b repaired by the same method used for rivited
panels, be thoroughly investigated. Wrinkles over
structure. Rivets are a satisfactory substitute for
stringers which disappear when the rivet pattern is
bonded seams on the assemblies. The strength of
removed may be considered negligible.
However,
the bonded seams may be replaced by a single 3/32,
the stringer rivet holes may not align perfectly with
2117-AD rivet per running inch of bonded seam.
the skin holes because of a permanent "set" in the
The standard repair procedures outlined in AC43.
stringer.
If this is apparent, replacement of the
13-1 are also applicable to bonded doors.
stringer will usually restore the original strength
characteristics of the area. Wrinkles occuring on
open areas which disappear when the rivets at the
17-66. FUSELAGE TUBULAR STURCTURE.
edge of the sheet are removed, or a wrinkle which is
hand-removable, may often be repaired by the addi-
17-67. The fuselage tubular structure, illustrated in
tion of a 1/2 x 1/2 x .060-inch 2024-T4 extruded an-
figure 17-11, is fabricated of chrome-molybdenum
gle, riveted over the wrinkle and extended to within
4130 steel aircraft tubing welded together. Gussets,
1/16 to 1/8-inch of the nearest structural members,
channels, angles, tabs and fittings, also of 4130 steel,
Rivet pattern should be identical to the existing manu-
are welded to the tubular assembly to complete the
factured seam at the edge of the sheet.
Neglible dam- structure. The structure is not heat treated.
age to stringers, formed skin flanges, bulkhead chan-
nels, and like parts is similar to that for the wing
17-68. GENERAL CONSIDERATIONS.
Federal
stringers and ribs, outlined in paragraph 17-19. Aviation Regulations, Part 43, list persons author-
ized to perform repairs and outlines standards of
performance. Given in these standards of perfor-
17-11