Service difficulty report · Transducer · Bell 407

Difficulty date
November 29, 2013
Submitted
September 14, 2015
Operation
General aviation
Make and model
Bell 407
Engine
Allsn 250C47B
Part
Transducer
Part number
406001120107
Condition
Fouled
Location
Collectiv
Part time
1,758 hours
Stage of operation
TX
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

(CAN) DURING GROUND RUN, FADEC FAULT/DEGRADE LIGHT ILLUMINATED. PILOT ATTEMPTED TO SWITCH OFF ENGINE BUT COULD NOT, THEN SUCCESSFULLY SELECTED TO SWITCH OFF MANUALLY. INVESTIGATION INITIATED BY MRO, WHICH REVEALED THE COLLECTIVE PITCH (CP) TRANSDUCER FAILED. FURTHER INVESTIGATION REVEALED THAT COLLECTIVE PITCH TRANSDUCER WAS STUCK DUE FOULED RELATIVE. MOVEMENT LATERALLY AND AXIALLY OF CONNECTING CLAMP 406-001-120-107 OVER JACKSHAFT ASSY 407-001-100-105. THE CLAMP HAD SLIPPED FROM THE INSTALLED POSITION AND 1 OF THE LOBES OF THE CLAMP HAD STUCK WITH THE PANEL OF THE ADJOINING BULKHEAD. THIS RESULTED THE COLLECTIVE JAMMED IN DOWN POSITION. MRO NOTED THAT THERE WAS A MARK WHICH EXISTED EARLIER ON THE SAME BULKHEAD REVEALING CLAMP FOULING PREVIOUSLY AND A PAINT TOUCHED UP.

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