8-20
ENSTROM 280FX OPERATOR’S MANUAL
Rev. 6
Report No. 28-AC-020
Feb 21/12
a location below 6000 ft. Figure 8-2 should be used if the
helicopter is based at a location above 6000 ft. To check
the autorotation RPM, proceed as follows:
(1) Determine the weight of the helicopter as it will be
flown (reference Section 6). It is important to
accurately know the gross weight of the helicopter
including fuel and occupants during this test.
(2) Establish the helicopter in a stabilized autorotation
at 60 MPH with the collective full down. Do not
allow the rotor RPM to exceed 385 RPM or to fall
below 332 RPM. This autorotation should be
conducted over a suitable landing area in case of
engine failure. The autorotation should be entered
high enough to allow the pilot to stabilize the
autorotation, record the necessary data, and
recover from the autorotation at a safe altitude.
(3) Once the autorotation is stabilized, record the rotor
RPM, the outside air temperature (OAT), and the
pressure altitude (with the altimeter set to 29.92
inches Hg). It is important that the autorotation is
stabilized before these readings are taken.
(4) Compare these readings with the information
provided in Figure 8-1 or 8-2, as appropriate.
(5) If the RPM is not correct as indicated by the
appropriate schedule, adjust the RPM as described
in Section 12 of the Maintenance Manual.
(6) If the RPM is adjusted, re-check the RPM as
described in steps (1) through (5) of this procedure.
13. Blade Tape
Leading edge tape, as supplied by Enstrom Customer
Service, can be installed on the leading edges of the main
rotor blades. This tape will provide some corrosion
protection for the main rotor blades. If this
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