ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT
Rev.
4
MM-21-13
Jun
21/12
(7)
Run up the aircraft in accordance with the operator’s manual. Check the CLUTCH
ENGAGE warning light extinguishes and the ROTOR RPM light illuminates when the
clutch is engaged.
(8)
Increase the power to bring rotor up to 334 rpm and check the ROTOR RPM warning
light extinguishes at 333 ± 1 rpm. If the light does not illuminate or extinguish at 333
± 1 rpm, refer to paragraph D, step (2)a for adjustment.
WARNING
The following test procedure requires flying the aircraft in an autorotation. The
test should be conducted by an appropriately rated pilot using appropriate
safety precautions.
(9)
Fly the aircraft to an altitude and location where an autorotation can be safely
performed and recovered.
(10) Enter a stabilized autorotation and allow the rotor RPM to build to the upper red line,
385 RPM
CAUTION
Rotor RPM can build very quickly in autorotation. Use care when approaching
the upper red line.
NOTE
The aircraft will have to be moderately heavy to achieve a high enough
autorotation RPM. An accelerated maneuver, such as a turn or flare, may also
be required to increase the RPM.
(11) Check that the ROTOR RPM warning light illuminates above 385 ± 2 RPM. Do not
allow the rotor RPM to exceed 390.
NOTE
If the collective is fully down, the horn and tone will not activate.
(12) Bring RPM down. Check that the ROTOR RPM warning light extinguishes below 385
± 2 RPM.
(13) If the warning light does not illuminate or extinguish at 385 ± 2 RPM, refer to
paragraph D, step (2)b for adjustment.
(14) Check the operation of the ROTOR RPM and CLUTCH ENGAGE warning lights
during the shutdown procedure
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