Service difficulty report · Modulator · Bolkms BK117A4

Difficulty date
June 12, 2008
Submitted
July 24, 2008
Operation
Air carrier
Aircraft
N158BK
Make and model
Bolkms BK117A4
Engine
Lyc LTS101650A2
Part
Modulator
Part number
430110212
Condition
Sticking
Location
Nr 2 Air Flow
Stage of operation
NR
How discovered
O
Nature of condition
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 ANNUAL TRAINING/CHECK RIDE, THERE DEVELOPED AN UNCOMMANDED, INTERMITTENT TORQUE SPLITS OF UP TO 25 PERCENT WITH NO COLLECTIVE MOVEMENTS OR TORQUE MATCHING ATTEMPTS. N1 AND TOT INDICATIONS FOLLOWED EACH ENGINE THROUGH THE SPLITS. FURTHER TROUBLESHOOTING PROVIDED NO CONCLUSIVE REASON FOR THESE SPLITS. THIS AIRCRAFT HAD EXPERIENCED THE SAME PROBLEMS JUST A COUPLE OF WEEKS AGO AND HAD AN ENGINE CHANGE AS A RESULT. DECISION WAS MADE TO RETURN AC TO AN AIRFIELD INSTEAD OF THE HOSPITAL PAD DUE TO THE DESIRE TO SHOOT A SINGLE-ENGINE PROFILE TO LANDING. EMERGENCY WAS DECLARED TO TOWER AND A SUCCESSFUL RUN-ON LANDING ACCOMPLISHED. AFTER MAINT EVALUATION AND TROUBLESHOOTING, IT WAS DETERMINED TO BE THE AIR FLOW MODULATOR (FENCE ACTUATOR) THAT WAS STICKING. (K)