TESTING AND TROUBLESHOOTING
61-00-15
Page 4-6
Rev. 24 Dec/20
Propeller Owner's Manual
115N
(3) Decrease in engine speed while increasing airspeed:
(a) Non-feathering (-1) propeller:
1 Governor pilot valve is stuck and is excessively
increasing oil volume.
(b) Feathering (-2, -5) or Aerobatic (-4) propeller:
1 Governor pilot valve is stuck and is excessively
decreasing oil volume.
2 Feathering command engaged on propeller pitch
control (-2, -5 propeller only).
(4) Increase in engine speed while decreasing airspeed:
(a) Non-feathering (-1) propeller:
1 Governor pilot valve is stuck and is excessively
decreasing oil volume.
(b) Feathering (-2, -5) or Aerobatic (-4) propeller:
1 Governor pilot valve is stuck and is excessively
increasing oil volume.
(5) Decrease in engine speed while decreasing airspeed:
(a) Non-feathering (-1) propeller:
1 Governor is not reducing oil volume in propeller.
2 Excessive friction in blade bearings or pitch
changing mechanism.
(b) Feathering (-2, -5) or Aerobatic (-4) propeller:
1 Governor is not increasing oil volume in
propeller.
2 Air charge (-2, -5) too high. Refer to Air Charge in
the Maintenance Practices chapter of this manual.
3 Engine transfer bearing leaking excessively.
4 Excessive friction in blade bearings or pitch
changing mechanism.
