Service difficulty report · Shield · Bolkms BO105S

Difficulty date
July 4, 2004
Submitted
August 13, 2004
Operation
Air carrier
Filed by
HDNR610E
Metro Aviation, Inc
Aircraft
N911EB
Make and model
Bolkms BO105S
Aircraft serial
S812
Aircraft time
5,721 hours
Engine
Allsn 250C20B
Engine time
12,999 hours, 18,936 cycles
Part
Shield
Part number
E23062750
Part serial
LN2972
Condition
Separated
Location
Nozzle
Stage of operation
TX
How discovered
V
Nature of condition
B
Precautionary procedure
E

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

What was found

THE NR 1 NOZZLE SHIELD DOME SEPARATED CAUSING THE TURBINE NR 8 BEARING SCAVENGE STRUT TO CLOG WITH CARBON INDUCED BY THE EXCESS HEAT ALLOWED IN THE AREA BY THE MISSING DOME. WHEN THE SCAVENGE FLOW WAS COMPLETELY LOST, THE OIL WAS FORCED THROUGH THE NR 8 LABYRINTH SEAL CAUSING SMOKING AND AN EXTREMELY HIGH RATE OF OIL CONSUMPTION. INSPECTION OF THE NOZZLE SHIELD BRAZE JOINT REVEALS, WHAT APPEARS TO BE, A LACK OF 100 PERCENT BRAZE COVERAGE IN THE JOINT. PART WAS SENT TO EXTEX FOR INVESTIGATION. NOTE THAT THIS APPEARS TO HAVE BEEN CAUSED BY A LACK OF BRAZE MATERIAL AND DIFFERS FROM THE BRAZE CRACKING PROBLEM THAT IS COVERED BY CEB 1370.