Service difficulty report · Thrust Plate

Difficulty date
November 6, 2009
Submitted
December 1, 2009
Operation
General aviation
Engine
Allsn 250C30S
Part
Thrust Plate
Part number
23058137
Condition
Damaged
Location
Tab
Stage of operation
IN
How discovered
V
Nature of condition
J
Precautionary procedure
K

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

What was found

(CAN) CUSTOMER COMPLAINT OF METAL GENERATION. ENG WAS INDUCTION TESTED AND CUSTOMER COMPLAINT WAS CONFIRMED. UPON DISASSEMBLY OF NR 8 BRG AREA, IT WAS NOTICED PN 23058137 GP BG THRUST PLATE WAS DAMAGED. PN 23058137 THRUST PLATE HAS A LOCKING TAB OR KEY THAT PREVENTS THE NR 8 BRG FROM SPINNING. THIS LOCKING TAB WAS FOUND TO BE WEDGED INTO THE GP SUPPORT. FURTHER DISMANTLING AND INSP CONFIRMED THE "LOCKING TAB" OF THE PLATE WAS BROKEN OFF AT THE BRAZE JOINT. THE NR 8 BRG OUTER RACE CUT INTO THE "LOCKING TAB" LIKELY CREATED THE SOURCE OF THE METAL THAT WAS FOUND ON THE TOP PLUG. THE LOCKING TAB`S PURPOSE IS TO PREVENT THE NR 8 BRG OUTER RACE FROM SPINNING. THIS IS ACCOMPLISHED BY "LOCKING" THE NR 8 BRG OUTER RACE TO THE GP SUPPORT. REVIEW OF THE PRINT FOR PN 23058137 SPECIFIES THAT THE BRAZE JOINT BETWEEN THE LOCKING TAB AND PLATE IS A CLASS 1 FURNACE BRAZE JOINT. A CLASS 1 BRAZE JOINT REQUIRES A MINIMUM OF 80 PERCENT BOND. THE OEM HAS BEEN CONTACTED REGARDING THIS PROBLEM.