Hartzell HC-D2MV20-3 Series, Owner'S Manual And Logbook

Page: 154 / 204

Propeller Owner's Manual
140
TESTING AND TROUBLESHOOTING
61-00-40
Page 4-10
Rev. 1 May/11
J. Hunting and Surging (Governing Propeller Only)
Hunting is characterized by a cyclic variation in engine speed
above and below desired speed. Surging is characterized
by a large increase/decrease in engine speed, followed by a
return to set speed after one or two occurrences.
(1) If propeller is hunting, a repair facility should check:
(b) Fuel control
(c) Check propeller rigging
(2) If propeller is surging:
Perform the steps under "Operational Tests," Steps
1.A. (1) through 1.A.(5). If surging reoccurs, it is most
likely due to a faulty governor.
Hunting and/or surging may also be caused by friction or
internal propeller corrosion that causes the propeller to
react slower to governor commands. The propeller must
be tested on a test bench at a propeller repair facility to
isolate these faults.
K. Engine Speed Varies with Flight Altitude (or Airspeed)
Small variances in engine speed are normal and are no
cause for concern.
L. Vibration
CAUTION: ANY VIBRATION THAT CAN BE
DESCRIBED AS APPEARING SUDDENLY,
OR IS ACCOMPANIED BY UNEXPLAINED
GREASE LEAKAGE SHOULD BE
INVESTIGATED IMMEDIATELY BEFORE
FURTHER FLIGHT.
NOTE: Vibration problems caused by propeller system
imbalance are normally felt throughout the RPM
range, with the intensity of vibration increasing
with RPM. Vibration is also a symptom of
resonance and potentially harmful to the propeller.
Avoid operation until the propeller can be checked
by an authorized repair station.