kc 43.13-14 1972
c. Axle Assemblies. Representative types of repairable and nonrepairable landing gear axle assemblies are shown in figure 2.16. The types as shown in A, B, and C of this figure are formed from steel tubing and may be repaired by the applicable method shown in figures 2.5 thru 2.15 in this Advisory Circular. However, it will always be necessary to ascertain whether or not the members are heat treated.
The axle assembly as shown in figure
2.16(D) is, in general, of a nonrepairable type for the following reasons:
(1) The axle stub is usually made from a highly heat-treated nickel alloy steel and carefully machined to close tolerances. These stubs are usually replaceable and should be replaced if damaged.
(2) The oleo portion of the structure is generally heat-treated after welding and is perfectly machined to assure proper functioning of the shock absorber. These parts would be istorted by welding after machining.
J. BUILT-UP TUBULAR WING OR TAIL SURFACE ARS. Repair built-up tubular wing or tail surce spars by using any of the applicable plices and methods of repair shown in figures 5 through 2.15 provided the spars are not eat-treated. In the case of heat-treated spars, he entire spar assembly would have to be reeat-treated to the manufacturer's specificaons after completion of the repair. In genal, this will be found less practicable than placing the spar with one furnished by the anufacturer.
WING AND TAIL BRACE STRUTS. In general, 'ill be found advantageous to replace damwing-brace struts made either from ded or streamlined tubing with new mempurchased from the original manufac- However, there is no objection from an rthiness point of view to repairing such ers in a proper manner. An acceptable d, in case streamlined tubing is used, will nd in figure 2.18. Repair similar memnade of round tubes using a standard as shown in figures 2.5, 2.7, or 2.8.
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 attachment is not considered an end fitting; therefore, a splice may be made at this point. The repair procedure and workmanship should be such as to 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 characteristics of the strut and attaching components are not adversely affected by the repair. A wide range of speed and enginepower combination must be covered during this check.
(1) Fit and Alignment. When making repairs to wing and tail surface brace members, pay particular attention to proper fit and alinement to avoid distortion.
82, REPAIRS TO WELDED PARTS. Repairs to welded assemblies may be made by:
a. Repiacing welded joints-cutting out the welded joint and replacing it with one properly gusseted, or
b. Replacing weld deposit-chipping out the metal deposited by the weld process and rewelding after properly reinforcing the joint by means of inserts or external gussets.
83. STAINLESS STEEL STRUCTURE. Repair structural components made from stainless steel, particularly the "18-8" variety (18 percent chromiun, 8 percent nickel), joined by spot welding in accordance with the instructions furnished by the manufacturer. Substitution of bolted or riveted connections for spot-welded joints are to be specifically approved by an authorized representative of the FAA.
a. Secondary Structural and Nonstructural Elements. Repair such elements as tip-bows or leading and trailing edge tip-strips of wing-andcontrol surfaces by soldering with a 50-50 lead-tin solder or a 60-40 alloy of these metals.
For best results use a flux of phosphoric acid (syrup). Since the purpose of flux is to attack the metal so that the soldering will be effec- Par 79
Page 48 AC 43.13-:
19:
tive, remove excess flux by washing the joint. welded seams in boat hulls, fuel tanks, etc., in Due to the high-heat conductivity of the stain- similar manner.
less steel, use a soldering iron large enough to do the work properly. Repair leaky spot- 84.~94. RESERVED.
Par 83
lAC 43.13-1A Page 49 1972 Section 3. METAL REPAIR PROCEDURES
95. RIVETED OR BOLTED STEEL TRUSS-TYPE STRUC- TURES. Repairs to riveted or bolted steel trusstype structures should be made, employing the general principles outlined in the following paragraphs on aluminum alloy structures.
Methods for repair of vital members should be specifically approved by a representative of the Federal Aviation Administration.
96. ALUMINUM ALLOY STRUCTURES. Extensive repairs to damaged stressed skin on monocoque types of aluminum alloy structures should preferably be made in accordance with specific recommendations of the manufacturer of the aircraft. In many cases, repair parts, joints, or reinforcements can be designed, and proof of adequate strength shown, without the calculaion of the design loads and stresses, by properly considering the material and dimensions f the original parts and the riveted attachments. Examples illustrating the principles of this method as applied to typical repairs are given in this handbook, or may be found in extbooks on metal structures. An important point to bear in mind in making repairs on nonocoque structures is that a repaired part must be as strong as the original with respect to all types of loads and general rigidity.
a. Use of Annealed Alloys for Structural Parts.
he use of annealed 2017 or 2024 for any ructural repair of an aircraft is not consided satisfactory because of its poor corrosionisting properties.
Hygroscopic Materials Improperly Moisturefed. The use of hygroscopic materials imberly moisture-proofed, such as impregd fabrics, or leather, and the like, to effect r-tight joints and seams is not an acceptacactice.
rilling Oversized Holes. Avoid drilling zed holes or otherwise decreasing the effective tensile areas of wing-spar capstrips, wing, fuselage, or fin longitudinal stringers, or other highly stressed tensile members. Make all repairs or reinforcements to such members in accordance with factory recommendations or with the specific approval or a representative of the Federal Aviation Administration.
d. Disassembly Prior to Repairing. If the parts to be removed are essential to the rigidity of the complete structure, support the remaining structure prior to disassembly in such a manner as to prevent distortion and permanent damage to the remainder of the structure.
When rivets are to be removed, weaken the rivet head by drilling. Use a drill of the same size as the rivet. Drilling must be exact center and to the base of the head only. After drilling, break off the head with a pin punch and carefully drive out the shank. Removal of rivet heads with a cold chisel and hammer is not recommended because skin damage and distorted rivet holes will probably result. Care must also be taken whenever screws must be removed for disassembly or removal of stress plates, access plates, fillets, etc., to avoid damage to adjoining structure. When properly used, impact wrenches can be effective tools for removal of screws; however, damage to adjoining structure may result from excessive vertical loads being applied through the screw axis.
Excessive loads are usually related to improperly adjusted impact tools or attempting to remove screws that have seized from corrosion.
Remove seized screw by drilling and use of a screw extractor. Structural cracks may appear in the doubler or tang that runs parallel to the line of anchor or plate nuts installed for securing access doors or plates. Inspect rivet joints adjacent to damaged structure for partial failure (slippage) by removing one or more rivets to see if holes are elongated or the rivets have started to shear.
Por 95
97. SELECTION OF ALUMINUM FOR REPLACEMENT PARTS. In selecting the alloy, it is usually satisfactory to use 2024 in place of 2017 since the former is stronger. Hence, it will not be permissible to replace 2024 by 2017 unless the deficiency in strength of the latter material is compensated by an increase in material thickness, or the structural strength is substantiated by tests or analysis. Information on the comparative strength properties of these alloys, as well as 2014, 6061, 7075, etc., is contained in MIL-HDBK-5, Metallic Materials and Elements for Flight Vehicle Structure.
The choice of temper depends upon the severity of the subsequent forming operations. Parts having single curvature and straight bend lines with a large bend radius may be advantageously formed from heat-treated material, while a part, such as a fuselage frame, would АС 43.13-11 197:
have to be formed from soft, annealed sheet and heat-treated after forming. Make sure sheet metal parts which are to be left unpainted are made of clad (aluminum coated) material. Make sure all sheet material and finished parts are free from cracks, scratches, kinks, tool marks, corrosion pits, and other defects which may be factors in subsequent failure.
a. Forming Sheet Metal Parts. Bend lines should preferably be made to lie at an angle to the grain of the metal (preferably 90°). Before bending, smooth all rough edges, remove burrs, and drill relief holes at the ends of bend bure, and lines and at corners, to prevent cracks from starting. For material in the heat-treated condition, the bend radius should be large. (See figure 2.17 for recommended bend radii.)
FIGURE 2.17.-Recommended radii for 90° bends in aluminum alloys.
Approximate sheet thickness (t) (inch) Alloy and temper
0.016 0.082 0.064 0.128 0.182 0.268 2024-01 0-1t O-1t 0-1t 0-1t 2024-T8** 133t-St 2t 4t 8t-5t 4t-6t 4t-8t 2024-T6' 2t 4t 8t-5t 3t-5t 4t-6t 5t-7t 5052-0 O-It 0-1t O-It 5052-H82 ½t-It ½ t-1½t est-1%t 5052-H84 3st-1½t 1½t-2½t 1½t-2½t 5052-H86 0-1t % t-1½t 1t-2t 1½t-St 2t-4t 5052-F88 36t-1t It-2t 1½t-3t 2t-1t 8₺-бt 6061-0 0-1t O-1t 0-1t O-1t 6061-T4 0-It 0-1t 1t-2t 1½t-St 6061-T6 0-1t ½t-1%t 1t-2t 1½t-St 2t-4t 7075-0 0-It 0-1t ½t-1½t 1t-21 7075-T6' 2t-4t 3t-5t 4t-6t St-7t ' Alclad sheet may be bent over slight smaller radif than the corresponding tempers of uncoated alloy.
' Immediately after quenching, this alloy may be formed over appreciably smaller radi..
98. HEAT TREATMENT OF ALUMINUM ALLOY PARTS. All structural aluminum alloy parts are to be heat-treated in accordance with the heattreatment instructions issued by the manufacturers of the materials. If the heat-treatment produces warping, straighten the parts immediately after quenching. Heat-treat riveted parts before riveting, to preclude warping and corrosion. When riveted assemblies are heated in a salt bath, the salt cannot be entirely Par 97 washed out of the crevices, thus causing cor sion.
a. Quenching in Hot Water or Air. Quench terial from the solution heat-treating temp ture as rapidly as possible, with a minir delay after removal from the furnace. Que ing in cold water is preferred, although drastic chilling (hot or boiling water blast) is sometimes employed for bulk
AC 43.13-1A 1972 tions, such as forgings, to minimize quenching stresses.
b. Transferring Too Slowly From Heat-Treatment Medium to Quench Tank, Transfer of 2017 alloys from the heat-treatment medium to the quenchtank should be accomplished as quickly as possible. An elapsed time of 10 to 15 seconds will, in many cases, result in noticeably impaired corrosion resistance.
c. Keheating af Temperatures Above Boiling Wafer. Reheating of 2017 and 2024 alloys at temperatures above that of boiling water after heat treatment, and the baking of primers at temperatures above that of boiling water, will not be considered acceptable without subsequent complete and correct heat treatment, as such practice tends to impair the original heat treatment.
99. RIVETING.
a. Identification of Rivet Material. Identification of rivet material is contained in Chapter
b. Replacement of Aluminum Alloy Rivets. All rotruding head rivets (roundhead, flathead, nd brazier head) may be replaced by rivets of he same type or by AN-470 Universal head ivets. Use flushhead rivets to replace flushbead rivets.
c. Replacement Rivet Size and Strength. Relace rivets with those of the same size and trength whenever possible. If the rivet hole pecomes enlarged, deformed, or otherwise damaged, drill or ream the hole for the next large ize rivet; however, make sure that the edge stance and spacings are not less than miniams listed in the next paragraph. Rivets may be replaced by a type having lower ength properties, unless the lower strength dequately compensated by an increase in or a greater number of rivets.
Replacement Rivet-Edge Distances and ngs for Sheet Joints. Rivet-edge distance is ed as the distance from the center of the hole to the nearest edge of the sheet.
spacing is the distance from the center rivet hole to the center of the adjacent Page 51 rivet hole. The following prescribes the minimum edge distance and spacing:
(1) Single row-edge distance not less than 2 times the diameter of the rivet and spacing not less than 3 times the diameter of the rivet.
(2) Double row-edge distance and spacing not less than the minimums shown in figure
2.18.
(3) Triple or multiple rows-edge distance and spacing not less than the minimums shown in figure 2.18.
•. Use of 2117-T3 Aluminum Alloy Replacement Rivets. It is acceptable to replace 2017-18 rivets of 8/16-inch diameter or less, and 2024-T4 rivets of 5/82-inch diameter or less with 2117-T8 rivets for general repairs, provided the replacement rivets are 1/82 inch greater in diameter than the rivets they replace and the edge distances and spacing are not less than the minimums listed in the preceding paragraph.
f. Driving of Rivels. The 2117 rivets may be driven in the condition received, but 2017 rivets above 8/16 inch in diameter and all 2024 rivets are to be kept either refrigerated in the "quenched" condition until driven, or be reheat-treated just prior to driving, as they would otherwise be too hard for satisfactory riveting. Dimensions for formed flat rivet heads are shown in figure 2.19, together with commonly found rivet imperfections.
g. Blind-Type and Hollow Rivets. Do not substitute hollow rivets for solid rivets in loadcarrying members without specific approval of the application by a representative of the Federal Aviation Administration.
Blind rivets may be used in blind locations in accordance with the conditions listed in Chapter 5, provided the edge distances and spacings are not less than the minimum listed in paragraph 99d.
h. New and Revised Rivet Patterns. Design a new or revised rivet pattern for the strength required in accordance with the specific instructions in paragraphs 100e and 100j.
A general rule for the diameter of rivets used to join dural sheets is to use a diameter ap- Par 98
Page 52 AC 43.13-14 1972
STRENGTH THROUGH THIS SECTION IS 78% OF SHEET WITHOUT HOLES.
D* DIAMETER OF 4D RIVET (PREFER- ABLY ABOUT 3X
THICKNESS OF
THICKER SHEET) 2D LADN →20 (A) DOUBLE ROW
STRENGTH THROUGH THIS SECTION IS 83% OF SHEET WITHOUT HOLES.
6D 30 20- *20 (B) TRIPLE OR MULTIPLE ROWS FIOURE 2.18.-Rivet hole spacing and edge distance for single-lap sheet splices.
Par 99
AC 43.13-1A Page 53 1972 -1žD 650 (ID MIN.) + 1¿0→ (MIN.) (gO MIN.)
(8) DIMENSIONS FOR FORMED RIVET HEADS,
INCORRECT CORRECT SHAPE FOR
RIVET OR SEE SET.
BUCKING BAR
(6) RIVETING TOOLS OR DOLLY.
RIVET DRIVEN AT SLANT RIVET DRIVEN RIVET FLAT ON ONE
CORRECTLY, DOLLY SIDE OR DOLLY HELD HEAD AT SLANT. FLAT.
BODY OF RIVET TOO RIVET NOT PULLED RIVET TIGHT, PLATES SHORT. CLOSING HEAD TIGHT, CLINCHES BULGED ON ACCOUNT SHAPED TOO MUCH BETWEENPLATES, OF POOR FIT.
WITH SNAP DIE. CLOSING HEAD TOO FLAT.
RIVETED TOO MUCH. RIVET BODY CLINCHED TOO MUCH, HEAD CRACKED.
PLATES CLINCHED AT RIVET MATERIAL TOO AND DRIVEN APART. HARD WHEN RIVETING TOOL FORMED.
DAMAGED PLATE 1C) RIVET, IMPERFECTIONS:
FIGURE 2.19.-Riveting practice and rivet imperfections.
Par 99
proximately 8 times the thickness of the thicker sheet. Do not use rivets where they would be placed in tension tending to pull the heads off. Back up a lap joint of thin sheets by a stiffening section.
100. REPAIR METHODS AND PRECAUTIONS FOR ALUMINUM STRUCTURE. Carefully examine all adjacent rivets after the repair or alteration is finished to ascertain that they have not been harmed by operations in adjacent areas.
Drill rivet holes round, straight, and free from cracks. The rivet-set used in driving the rivets must be cupped slightly flatter than the rivethead as shown in figure 2.19. Rivets are to be driven straight and tight, but not overdriven or driven while too hard, since the finished rivet must be free from cracks. Information on special methods of riveting, such as flush riveting, usually may be obtained from manufacturer's service manuals.
a. Splicing of Tubes. Round or streamline tubular members may be repaired by splicing as shown in figure 2.20. Splices in struts that overlap fittings are not acceptable.
When solid rivets go completely through hollow tubes, their diameter must be at least one-eighth of the outside diameter of the outer tube. Rivets which are loaded in shear should be hammered only enough to form a small head, and no attempt made to form the standard roundhead. The amount of hammering required to form the standard roundhead often causes the rivet to buckle inside the tube. Satisfactory rivetheads may be produced in such installations by spinning, if the proper equipment is available. (Correct and incorrect examples of this type of rivet applications are incorporated in figure 2.20.)
b. Repairs to Aluminum Alloy Members, Make repairs to aluminum alloy members with the same material or with suitable material of higher strength. The 7075 alloy has greater tensile strength than other commonly used aluminum alloys such as 2014 and 2024, but is subject to somewhat greater notch sensitivity.
In order to take advantage of its strength characteristics, pay particular attention to de- Par 99 AC 43.13-11 1971 sign of parts to avoid notches, small radil large or rapid changes in cross sectional areas In fabrication, exercise caution to avoid proc essing and handling defects, such as machine marks, nicka, dents, burrs, scratches, and forming cracks. Cold straightening or forming of 7075-16 can cause cracking; hence, it may be advisable to limit this processing to minor cold straightening.
c. Wing and Tail Surface Ribs. Damaged aluminum alloy ribs either of the stamped sheetmetal type or the built-up type employing special sections, square or round tubing, may be repaired by the addition of suitable reinforcement. (Acceptable methods of repair are shown in figures 2.21 and 2.22.) These examples deal with types of ribs commonly found in small and medium aircraft. Repair schemes developed by the aircraft manufacturer are acceptable, and any other methods of reinforcement will be specifically approved by a representative of the FAA.
(1) Trailing and Leading Edges and Tip Strips Repairs to wing and control surface trailin and leading edges and tip strips should made by properly executed and reinforce splices. Acceptable methods of trailing edge r pairs are shown in figure 2.23.
d. Repair of Damaged Skin. In case metal ski is damaged extensively, make repairs replacir an entire sheet panel from one structural mer ber to the next. The repair seams are to along stiffening members, bulkheads, etc., ai each seam must be made exactly the same i regard to rivet size, splicing, and rivet patter as the manufactured seams at the edges of th original sheet. If the two manufactured sear are different, the stronger one will be copi (See figure 2.24 for typical acceptable meth of repairs.)
(1) Patching of Small Holes. Small hole skin panels which do not involve damage to stiffening members may be patched by c ing the hole with a patch plate in the me shown in figure 2.24.
Flush patches also may be install stressed skin-type construction. An acce and easy flush patch may be made by trit
AC 43.13-1A 1972 maining reinforcement tube. Allow one sleeve weld to cool before welding the remaining tube to prevent undue warping.
76. SPLICING USING LARGER DIAMETER REPLACE- MENT TUBES. The method of splicing structural tubes, as shown in figure 2.10, requires the least amount of cutting and welding. However, this splicing method cannot be used where the damaged tube is cut too near the adjacent cluster-joints, or where bracket-mounting provisions make it necessary to maintain the same replacement tube diameter as the original. As an aid in installing the replacement tube, squarely cut the original damaged tube leaving a minimum short stub equal to 2 1/2-tube diameters on one end and a minimum long stub equal to 41/2-tube diameters on the other end.
Select a length of steel tube of the same material and at least the same wall thickness, having an inside diameter approximately equal to he outside diameter of the damaged tube. Fit Page 39 this replacement tube material snugly about the original tube with a maximum diameter difference of 1/16 inch. From this replacement tube material, cut a section of tubing diagonally (or fishmouth) of such a length that each end of the tube is a minimum distance of 11/2-tube diameters from the end of the cut on the original tube. Use a fishmouth cut replacement tube wherever possible. Remove the burr from the edges of the replacement tube and original tube stubs. If a fishmouth cut is used, file out the sharp radius of the cut with a small round file. Spring the long stub of the original tube from the normal position, slip the replacement tube over the long stub, then back over the short stub. Center the replacement tube between the stubs of the original tube. In several places tack-weld one end of the replacement tube, then weld completely around the end. In order to prevent distortion, allow the weld to cool completely, then weld the remaining end of the replacement tube to the original tube,
ZZA- REPLACEMENT TUBE ORIGINAL → ZA TUBE
- ІзА-→
FREPLACEMENT TUBE 47 A
ORIGINAL TUBE
•А- FIGURE 2.10. Splicing using larger diameter replacement tube.
Par 75
77. REPAIRS AT BUILT-IN FUSELAGE FITTINGS.
Make splices in accordance with the methods described in paragraphs 70 through 75. Repair built-in fuselage fittings in the manner shown in figure 2.11. The following paragraphs outline the different methods as shown in the figure:
a. Tube of Larger Diameter Than Original. A tube (sleeve) of larger diameter than original is used in the method shown in figure 2.11(A).
This necessitates reaming the fitting holes (at longeron) to a large diameter. The forward splice is to be a 80° scarf splice. Cut the rear longeron (right) approximately 4 inches from the centerline of the joint and a spacer 1 inch long fitted over the longeron. Edge-weld this spacer and longeron; make a tapered "V" cut approximately 2 inches long in the aft end of the outer sleeve and swage the end of the outer sleeve to fit the longeron and weld.
b. Tube of Same Diameter as Original. In the method shown in figure 2.11(B) the new section is the same size as the longeron forward (left) of the fitting. The rear end (right) of the tube is cut at 80° and forms the outside sleeve of the scarf splice. A sleeve is centered over the forward joint as indicated.
c. Simple Sleeve. It is assumed the longeron is the same size on each side of the fitting in this case, figure 2.11(C), and it is repaired by a simple sleeve of larger diameter than the longeron.
d. Large Difference in Longeron Diameter Each Side of Fitting. Figure 2.11(D) assumes that there is 1/4 inch difference in the diameter of the longeron on the two sides of the fitting.
The section of longeron forward (left) of the fitting is cut at 30°, and a section of tubing of the same size as the tube and of such length as to extend well to the rear (right) of the fitting is slipped through it. One end is cut at 30° to fit the 30° scarf at left and the other end fishmouthed as shown. This makes it possible to insert a tube of such diameter as to form an inside sleeve for the tube on the left of the fitting and an outside sleeve for the tube on the right of the fitting.
Par 77 AC 43.13-1 19
78. ENGINE MOUNT REPAIRS. All welding on a engine mount should be of the highest qualit since vibration tends to accentuate any minc defect. Engine-mount members should prefers bly be repaired by using a larger diameter r placement tube telescoped over the stub of th original member and using fishmouth and r‹ sette welds. However, 30° scarf welds in plac of the fishmouth welds will be considered ac ceptable for engine-mount repair work.
a. Check of Alignment. Repaired engin mounts must be checked for accurate align ment. When tubes are used to replace bent o damaged ones, the original alignment of th structure must be maintained. This can b done by measuring the distance betwee points of corresponding members that have no been distorted, and by reference to the manu facturer's drawings.
b. Cause for Rejection. If all members are out of alinement, reject the engine mount and re place by one supplied by the manufacturer one which was built to conform to the man facturer's drawings. The method of checki, the alignment of the fuselage or nacelle poir should be requested from the manufacturer.
c. Engine Mount Ring Damage. Repair mino damage, such as a crack adjacent to an engir attachment lug, by rewelding the ring and etending & gusset or a mounting lug past th damaged area. Engine mount rings which a extensively damaged must not be repaired, u less the method of repair is specifically a proved by an authorized representative of t FAA, or the repair is accomplished in acco!
ance with FAA approved instructions nished by the aircraft manufacturer.
79. LANDING GEAR REPAIR.
a. Round Tube Construction. Repair lar gears made of round tubing using standa pairs and splices as shown in figures 2.
2.11.
b. Streamline Tube Construction. Repaiz ing gears made of streamlined tubing by one of the methods shown in figures 2.
2.15.
lAC 49.13-1A Page 45 1978
- GAP}"
• 6А ЗА 2t 2t ЗА ЗА 6A - 30° ттт A- STREAMLINE TUBE LENGTH OF MINOR AXIS, PLATE WIDTHS.
B- DISTANCE OF FIRST PLATE FROM LEADING EDGE, /3 A.
C- STREAMLINE TUBE LENGTH OF MAJOR AXIS.
S.L. SIZE ,572 „382 1,340 3,43 .714 ,476 1,670 4.28 1-/₴ .858 .572 2.005 5.15 1-4 1,000 ,667 2,339 6,00 . 2 1,144 ,762 2,670 6.86 2-¼ 1,286 .858 3.008 7,72 2-2 1.430 .954 3.342 8.58 FIGURE 2.15.-Streamline tube splice using plates (applicable to landing gears).
Par 79
Page 46 AG 43.131 (A)
(8) (C) (A), (B), AND (C) ARE TYPES OF REPAIRABLE AXLE
ASSEMBLIES, ASSEMBLIES ORIGINALLY HEAT-TREATED MUST BE REHEAT-TREATED AFTER WELDING.
(D) (D) IS A TYPE OF AXLE ASSEMBLY WHICH IS GENERALLY NONREPAIRABLE.
FIGURE 2.16.-Representative types of repairable and nonrepairable axle assemblies.
Par 79