TM 55-1520-240-23-5
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VIBRATION CORRECTION PROCEDURE (AVIATION VIBRATION
ANALYZER) (Continued)
6-217
23.
Reposition combining transmission forward
output shaft pinion adapter (16) as follows:
a.
Match-mark combining transmission forward
output shaft pinion adapter (16) to combining
transmission (6). Match-mark No. 7 shaft
(17) to No. 6 shaft (18). Use a marking pencil
(E270.1).
b.
Remove No. 7 shaft (Task 6-4).
c.
Remove adapter (16) from transmission (6)
(Task 6-6). Rotate it 120
clockwise and
reinstall it (Task 6-9).
d.
Reinstall No. 7 shaft (17) (Task 6-19)
according to No. 6 shaft (18) match-mark.
Before repeating ground run, check that rotor
blades are properly phased (Task 6-27.1).
24.
Repeat step 22. If check is still unsatisfactory,
repeat step 23. If vibration still exceeds 0.7 ips
replace the fan (Tasks 6-182 and 6-186).
NOTE
If fan has been replaced, repeat entire
vibration analysis.
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