Service difficulty report · Housing · Bell 206B

Difficulty date
August 27, 2003
Submitted
October 10, 2003
Operation
General aviation
Aircraft
N6181K
Make and model
Bell 206B
Aircraft serial
4276
Engine
Allsn 250C20
Part
Housing
Part number
4000395
Condition
Worn
Location
Rotor Brake
Part time
4,301 hours
Component
Rotor Brake
Component part number
40003972
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

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

What was found

DURING A 100 HOUR INSPECTION IT WAS FOUND THAT THE ROTOR BRAKE RETURN SPRING HAD WORN INTO THE HOUSING. THE SPRINGS ON ALL FOUR HOUSINGS WERE COCKED AT AN ANGLE FROM TRUE CENTER, ALLOWING THE SPRING TO WEAR A GROOVE INTO THE SIDE OF THE HOUSING. THIS GROOVE HINDERED THE SPRING ACTION TO MOVE THE PUCK EITHER IN OR OUT. THE CONCERN IS THAT THE SPRING COULD BUST, OR BIND UP NOT ALLOWING THE PUCK TO MOVE BACK OFF OF THE ROTOR DISK. THE RECOMMENDATION WOULD BE TO LENGTHEN THE RETURN PISTON GUIDE BORE WHERE THE PISTON RETURN PIN MOVES THRU THE HOUSING. THIS WOULD HELP KEEP EVERYTHING IN ALIGNMENT SO THE RETURN SPRING WILL ALWAYS MOVE STRAIGHT.

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