Page 4-7
Rev. 1 Jun/11
TESTING AND TROUBLESHOOTING
61-00-75
Propeller Owner's Manual
175
D
. Hunting and Surging
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:
(a) Governor
(b) Fuel control
(c) Synchrophaser, or synchronizer, if applicable.
(2) If propeller is surging:
(a) Perform the steps 1.A.(1) through 1.A.(5) under
Operational Tests section in this chapter to release
trapped air from the propeller. If surging reoccurs it is
most likely because of a faulty governor.
(b) Hunting and/or surging may also be caused by
friction or binding within the governor control, or
internal propeller corrosion, which causes the
propeller to react slower to governor commands.
NOTE:
The propeller must be tested on a test
bench at an appropriately licensed
propeller repair facility to isolate these
faults.
E
. Engine Speed Varies with Airspeed
(1) Constant speed propeller models HC-8( )( )( )-1( )( ),
-2( )( ), -3( )( ), and -6( )( )( ) will experience some small
variances in engine speed that are normal and are no
cause for concern.
(2) Increase in engine speed while descending or increasing
airspeed:
(a) HC-82(X,V)(F,L )-6( )( )( ) propeller models:
1
Governor is not increasing oil volume in the
propeller.
2
Engine oil transfer bearing is leaking
excessively.
3
Excessive friction in the blade bearings, in the
pitch change mechanism, or in the misalignment
between the guide collar and the piston rods.
OBSOLETE PROPELLER MODELS. SEE COVER PAGE
WARNINGS AND SERVICE BULLETIN HC-SB-61-331
