ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
8
MM-4-30
Sep
20/17
I.
Add 4 quarts of the gear lube currently used in the gearbox (ref. Table 4-1).
J. Manually rotate the main rotor hub to spin the gearbox 7-10 revolutions.
K. Remove the magnetic plug/chip detector and drain the gearbox. Collect the oil to
inspect for contamination. Repeat the flushing procedure until it drains free of contamination.
L. Inspect and clean the magnetic drain plug or chip detector, if installed.
M. Install and safety the magnetic drain plug/chip detector.
N. Install and secure the filter cap and tube assembly using a new P/N 28-13107-13 gasket.
O. Torque the bolts to 50-70 in-lb/5.6-7.9 Nm.
P. Service the gearbox (paragraph 4-12).
Q. Remove the blocks from under the forward skids and position the ground handling
wheels, as desired.
R. Install the left side upper access panel.
4-14. Tail Rotor Transmission
(Figure 4-1, View N)
4-15. Servicing – Tail Rotor Transmission
NOTE
Refer to Table 4-1 for system capacity and approved oils.
NOTE
When the tail rotor transmission is properly serviced (5 oz./.147 l), the sight
glass will be completely full. The transmission oil level is serviceable until
the oil level is at the center of the sight glass.
A. Check the oil level of the transmission by using the sight plug located in the aft side of
the transmission. The transmission is serviceable until the oil level is at the center of the sight
glass. Raise and lower the tail to change the attitude of the aircraft to verify the level of the oil in
the transmission if a bubble is present in the sight glass.
NOTE
Check the transmission for leaking seals if servicing is required between
periodic inspections.
B. Remove the filler port located directly above the sight glass.
C. Add 5 oz./.147 l of oil if servicing the transmission after draining or slowly add oil until
oil flows from the filler port.
D. Reinstall the filler plug (72-84 in lbs/8.1-9.5 Nm) and lockwire (.032) to the magnetic
plug/chip detector and the sight glass.
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