ENSTROM F-28F/280F SERIES MAINTENANCE
MANUAL
Rev.
7
MM-9-10
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
420
2
3
W
a
lk
ing be
am
bracket
Deformed o
r cra
cked
ears
Secu
rity of bushin
gs in
bra
c
ket – pre
ss fit
Nicks, scrat
c
hes, or
c
o
rr
os
ion
Non
e Allowe
d
No Play Allowed
Non
e Allowe
d
Not Repairabl
e
Not Repairabl
e
.010 Deep
Repl
ace Bra
cket
Repl
ace Bra
cket
Blend and Polish
Smooth
28-1
422
7
5
Nut
Thre
ad
s
(roll
ed or mi
ssing
)
Non
e Allowe
d
Not Repairabl
e
Repl
ace Nut
W-
09
6
Lockwasher
Tang
s
(defor
me
d or
c
rack
e
d)
Non
e Allowe
d
Not Repairabl
e
Repl
ace Lo
ckwa
s
he
r
28-1
423
6
7
DU wa
she
r
Flatness
Thick
n
ess
.090 to .093
.005
-.003
Not Repairabl
e
Not Repairabl
e
Repl
ace Wa
sher
Repl
ace Wa
sher
28-1
425
6
9
Nut
Thre
ad
s
(roll
ed or mi
ssing
)
Non
e Allowe
d
Not Repairabl
e
Repl
ace Nut
28-1
422
3
16
Space
r
Dowel Hole Dia. .3125
Bolt Hole Dia.
.313 to .318
+
.0
0
05
+.002
Not Repairabl
e
Not Repairabl
e
Repl
ace Spacer
Repl
ace Spacer
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