VIBRATION CORRECTION PROCEDURE (AVIATION VIBRATION
FAN DRIVE SHAFT
Loosen clamp (19) and remove duct (20) from
Inspect fan (21) for signs of contact between the
vanes of impeller (22) and housing (23). If there
is no evidence of contact, continue with step 28.
If there is evidence of contact, replace the fan
(Tasks 6-182 and 6-186).
Perform a ground run vibration check for the
combining transmission fan. If the check is
unsatisfactory (vibration greater than 0.3 ips),
continue with step 28.
Match-mark a vane on impeller (22) to housing
(23). Use a marking pencil (E270.1).
Raise fan assembly (21) from fan shaft (24) and
rotate slightly to rest on studs (Task 6-182).
Make sure the fan shaft remains engaged in the
transmission and does not rotate.
Rotate fan impeller (22) 90
respect to fan drive shaft (24). Refer to
match-marks. Install fan assembly (21) (Task
Oil (E254) is toxic. It can irritate skin
and cause burns. Avoid inhaling. Use
only with adequate ventilation. Avoid
contact with skin, eyes, or clothing.
In case of contact, immediately flush
skin or eyes with water for at least
15 minutes. Get medical attention
Install duct (20) and clamp (19). Coat thread of
clamp with oil (E254). Wear gloves (E184.2).
Torque clamp to 35 inch-pounds.
Repeat step 27. If check is still unsatisfactory,
repeat steps 29 thru 31 two times. If vibration
still exceeds 0.3 ips, replace the fan (Tasks
6-182 and 6-186).
If fan has been replaced, repeat entire