ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
8
MM-4-65
Sep
20/17
a.
Tail rotor transmission metal particles, flakes, or slivers exceeding .035
inch/.9mm: Contact Enstrom Customer Service Department and discontinue
use until further instructions are received from Enstrom Customer Service
Department.
NOTE
Sludge normally will not cause a chip indication by itself. There is normally a
small particle, flake, or sliver on the detector also.
b.
Sludge (a mixture of oil and fine metal particles resulting from normal gear
operation): Clean the detector and return the transmission to service.
C. Three main rotor or two tail rotor transmission chip indications occur within 10 flying
hours. Perform the following:
NOTE
Check the aircraft inspection records for any annotations about the condition
of the main rotor transmission ring and pinion gears or the tail rotor
transmission input and output gears.
(1) Drain the oil from the transmission and inspect the ring and pinion gears (main
rotor transmission) or the input and output gears (tail rotor transmission) for
cracks, excessive pitting, excessive spalling, or "hard wear" lines.
(2) Remove the tail rotor assembly from the tail rotor transmission output shaft and
the aft tail rotor drive shaft flex plate assembly. Turn the tail rotor transmission
output shaft by hand. If indications of a rough bearing are felt, the transmission
must be replaced.
NOTE
If the gearbox is to be returned to Enstrom Service, do not clean the metal from
the chip detector.
(3) If none of the above conditions are found, flush and service the transmission
(main rotor, para. 4-13.1; tail rotor, para. 4-16.1), and return to service. If two
chip indications occur within the next 10 flying hours, repeat the flush and
servicing procedure. If two additional indications occur within the next 10 flying
hours, contact Enstrom Helicopter Corporation for further instructions.
4-63. Engine Overboost – Special Instruction
A. Inspect the engine in accordance with the latest revision of Textron-Lycoming Service
Bulletin 369.
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