Page 4-10
Rev. 1 Jun/11
TESTING AND TROUBLESHOOTING
61-00-75
Propeller Owner's Manual
175
G
. Loss of Propeller Control - HC-8( )( )( )-1( )( ), -2( )( ), and
-3( )( ) propeller models:
(1) Propeller goes to uncommanded high pitch (or feather)
(a) Loss of propeller oil pressure - check:
1
Governor pressure relief valve for proper
operation
2
Governor drive for damage
3
Adequate engine oil supply
4
Engine oil transfer bearing for excessive leakage.
(b) Start lock not engaging - HC-8( )( )( )-1( )( ), -2( )( ),
and -3( )( ) propeller models only
(2) Propeller goes to uncommanded low pitch (high RPM)
(a) governor pilot valve sticking
(3) RPM increases with power and airspeed. Propeller RPM
control has little or no effect.
(a) Excessive friction in blade bearings or pitch change
mechanism
(b) Excessive friction in misalignment between the guide
collar and the piston rods - HC-8( )( )( )-1( )( ),
-2( )( ), and -3( )( ) propeller models only.
(c) Broken spring (applies to HC-8( )( )( )-2( )( ) and
-3( )( )propeller models.)
(d) Governor is not reducing oil volume in the propeller.
H
. Failure to Feather or Feathers Slowly - HC-8( )( )( )-2( )( ) and
-3( )( ) propeller models only:
(1) Broken feathering spring
(2) Check for proper function and rigging of the propeller/
governor control linkage.
(3) Check governor drain function.
(4) Propeller must be checked for misadjustment or internal
corrosion (usually in blade bearings or pitch change
mechanism) that results in excessive friction. This must
be accomplished at an appropriately licensed propeller
repair facility.
OBSOLETE PROPELLER MODELS. SEE COVER PAGE
WARNINGS AND SERVICE BULLETIN HC-SB-61-331
