ENSTROM F-28F/280F SERIES MAINTENANCE
MANUAL
Rev.
7
MM-9-11
Aug
22/16
Table 9-1. Main Rotor Hub Assem
bl
y
– Inspe
ction
Part No.
Figure 9-3
Item #
Part Name
Inspe
c
tion*
Service
able L
imi
ts*
Repair Limit
s
Repair or Action
28-1
422
3
(co
ntinue
d)
16
Space
r
(c
on
tinued
Nicks, scrat
c
hes, or
c
o
rr
os
ion
Cra
c
ks
.030 De
ep
Non
e Allowe
d
.010 Deep
Not Repairabl
e
Repl
ace Spacer
Repl
ace Spacer
28-1
422
4
12 & 18
Spline
Adaptors
Inboard face
of adapter
perpendi
cul
a
r to O.D.
O.D.
3.6235 to 3.6245
Spline pitting
Spline co
rrosi
on
Spline wear
Nicks, scrat
c
hes, or
c
o
rr
os
ion
Cra
c
ks
+.002
5 FIM
-.0005
.003 De
ep
Non
e Allowe
d
.0015 on Side
.010 De
ep
Non
e Allowe
d
Not Repairabl
e
Not Repairabl
e
Not Repairabl
e
Surface Co
rrosio
n
Not Repairabl
e
.010 Deep
Not Repairabl
e
Repl
ace Adapter
Repl
ace Adapter
Repl
ace Adapter
Wire B
ru
s
h to
Remove
Repl
ace adapTer
Blend and Polish
Smooth
Repl
ace Adapter
28-1
428
0
14
U
p
pe
r Hub
Spline Adapt
er Bore
3.624 to 3.625 diameter
U Block Beari
ng Bore
2.4986 to 2.4994
+
.0
0
05
+
.0
0
08
Not Repairabl
e
Not Repairabl
e
Repl
ace Upp
e
r Hu
b
Repl
ace Upp
e
r Hu
b
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