ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
8
MM-4-29
Sep
20/17
4-13. Draining – Main Rotor Transmission
A. Remove the access panel located below the left side fuel tank.
B. Place a trough under the chip detector/magnetic plug located by the aft left side
transmission mount and use a suitable container to collect the oil.
C. If equipped with a chip detector, remove the chip detector from the quick disconnect
receptacle.
D. Remove the quick disconnect receptacle/magnetic plug from the transmission to drain
the oil.
E. When the transmission is drained, replace the crush washer on the receptacle/
magnetic plug and reinstall receptacle/magnetic plug finger tight. Tighten an additional 90° and
lockwire the receptacle/magnetic plug.
F. If equipped with chip detector, reinstall the chip detector.
4-13.1 Flushing – Main Rotor Transmission
A. Lower the ground handling wheels (paragraph 4-67.B).
(1) Helicopters equipped with MRGB chip detector: Set 1.5 inch (4 cm) wood blocks
under the forward skid shoes raise the left side ground handling wheel
(paragraph 4-67.C).
(2) Helicopters not equipped with MRGB chip detector and having a forward MRGB
drain port: Install a block (2-3 inches) under the forward right skid plate and
leave both ground handling wheels in the lowered position.
B. Remove the left side upper access panel.
C. Drain the transmission oil (paragraph 4-13).
D. Remove the filler cap and tube assembly.
E.
Inspect
the
gears.
(1) Using a bright light source, inspect ring and pinion gear teeth for cracks, any
pitting, any spalling (frosting), or hard wear lines. Turn the transmission by
turning the upper pulley or the tail rotor.
F. Use a syphon sprayer with kerosene, mineral spirits, or equivalent oil-based solvent
to spray the interior of the gearbox. Direct the aim of the sprayer around the inside of the
gearbox and the ring gear and carrier while turning the gearbox.
(1) Use a sufficient volume of solvent to thoroughly flush out any debris.
G. Allow the MRGB to drain completely.
H. Loosely install the magnetic drain plug or chip detector, as applicable.
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