Service difficulty report · Brush Block · Bell 206B

Difficulty date
July 13, 2011
Submitted
September 9, 2011
Operation
Air carrier
Make and model
Bell 206B
Aircraft time
13,405 hours
Engine
Allsn 250C20B
Part
Brush Block
Condition
Failed
Location
Starter Gen
Component
Starter Gen · 23032018
Stage of operation
IN
How discovered
V
Nature of condition
O
Precautionary procedure
K

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

What was found

UNIDENTIFIED METAL PARTICLES FOUND IN ENGINE COMPARTMENT. DURING A ROUTINE BRUSH INSP OF THE STARTER GENERATOR, PN 23032-018, SN 14011, A SCREW WAS FOUND TO HAVE BEEN MAKING CONTACT WITH WHAT LOOKED TO BE AN IMPROPER OR IMPROPERLY INSTALLED SPRING WHICH IS USED FOR HOLDING THE BRUSH FIRMLY AGAINST THE COMMUTATOR. AN ALUMINUM WASHER UNDER THE HEAD OF THE SCREW WAS SEVERELY MELTED, AND IT IS BELEIVED THAT THE METAL PARTICLES IN THE ENGINE COMPARTMENT ARE COMPOSED OF THAT MELTED MATERIAL. THE BRUSHES WERE APPROX. 50 PERCENT WORN, AND IT IS BELIEVED THAT THE SPRING SHORTED AGAINST SAID SCREW AS THE BRUSH WORE DOWN PAST A GIVEN POINT.

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