TB l-1520-238-30-15
NOTE
The following inspections are performed on the aircraft with
T/R Blades installed.
e. Remove the three nuts securing the fork to the T/R Output Shaft. If any threads on the studs are
crossed, stripped, or flattened, or if obvious necking of the threads is evident on the stud, replace the bad
stud in accordance with paragraph 9.
CAUTION
Do not allow the T/R Head Assembly to rest on the studs
while the T/R Head Assembly is slid out. Excessive
bending loads may damage the studs.
f. Using two persons or an overhead hoist/crane to support the hub (while a third person performs the
inspection below) slide the T/R Head Assembly out approximately
inches. (Do not completely
remove the fork from the studs.)
g. Identify and number the studs using figures 1 through 3. The number 2 stud is the only stud
centered on a spline tooth. Mark the end of the number 1 stud, located counterclockwise from the number
2 stud, using torque stripe paint.
h. If the number 1 stud marked above does not correspond with the number 1 fork hole marked in
the fork was incorrectly indexed during installation. Replace all three studs per paragraph
NOTE
Axial wear of only the cadmium plating itself is not cause
for rejection.
i. Inspect studs for axial scoring/gouging into the parent material. If scoring is detected, the Head
Assembly was previously incorrectly indexed, and all three studs must be replaced per paragraph 9.
j. Check for radial wear marks (smiles) between l-112 and 2 inches outboard of the lockring, as
shown in figure 4. If these marks exist or corrosion prevents inspection in the area between l-112 and 2
inches outboard of the lockring, replace all three studs using paragraph 9.
CAUTION
MIL-A-9962 abrasive mat or equivalent is aluminum
oxide impregnated nylon webbing. Its use must be
limited to the corroded areas in order to minimize the
cadmium plating removal.
k. Check the remaining area on the studs for corrosion. (The remaining area is the area not between
1
and 2 inches outboard of the lockring.) General dulling of the surface is the first stage of corrosion.
Darkening of the cadmium plate finish is not cause for rejection. Corrosion will appear brown or red in
color. This corrosion is acceptable provided that deposits are easily removable with Scotchbrite, abrasive
mat (MIL-A-9962, very fine, NSN
or equivalent. To remove corrosion, the Scotchbrite
must be cut into a strip just wide enough to cover the corrosion products. The use of wider strips will
remove cadmium plating, which will degrade the corrosion protection available. Apply Corrosion
Preventive Compound, MIL-C-16173, Grade IV or equivalent to studs prior to reassembly. If corrosion
cannot be easily removed, replace corroded studs in accordance with paragraph 9.
IETM. Replace studs if free play
I. Check studs for looseness per TM l-1
exceeds 0.022 inch.
4
