Service difficulty report · Governor · Bolkms BK117A4

Difficulty date
January 5, 2017
Submitted
January 6, 2017
Operation
Air carrier
Aircraft
N4XBDW
Make and model
Bolkms BK117A4
Aircraft serial
7092
Aircraft time
9,799 hours
Engine
Lyc LTS101650B1
Engine time
7,143 hours
Part
Governor
Part number
430121204
Part serial
88090177
Condition
Malfunctioned
Location
Engine
Stage of operation
CR
How discovered
O
Nature of condition
R, J
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

DURING CRUISE FLIGHT, SUDDEN LOSS OF RIGHT ENGINE POWER ACCOMPANIED WITH HELICOPTER YAW MOVEMENT AND NR 2 ENGINE LOW LIGHT. SIGNIFICANT SPLIT IN TORQUE, N2 AND NR NEEDLES. IN A FEW SECONDS THE NR 2 ENGINE CAME BACK TO HIGH POWER WITH N2 & NR RISING TO 106-108%. PILOT RAISED COLLECTIVE IN ORDER TO STOP RPM RISING AND THEN CLOSED RIGHT THROTTLE TO IDLE POSITION. INTERNAL GOVERNOR FAILED. SUSPECTED CATASTROPHIC BEARING FAILURE, RESULTING IN MAJOR SHAFT MOVEMENT. REPLACED THE GOVERNOR ON ENGINE WITH SERVICEABLE UNIT. PERFORM ENGINE OVERSPEED INSPECTION.