Service difficulty report · B-Nut · Cirrus SR22

Difficulty date
January 22, 2009
Submitted
January 30, 2009
Operation
General aviation
Aircraft
N377SR
Make and model
Cirrus SR22
Aircraft serial
2504
Engine
Cont IO550N
Part
B-Nut
Condition
Loose
Location
Oil Line
Part time
796 hours
Component
Oil Line
Component part number
AN9192
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

WHILE PERFORMING A 100 HR INSP ON AN ENGINE, THE OIL LINES FOR THE TURBO NORMALIZED SYS WERE BEING CHECKED FOR SECURITY. MX TO OIL LINE THAT CONNECT BETWEEN THE MANIFOLD PRESSURE CONTROLLER AND THE MASTER WASTE GATE IN HIS HAND, APPLIED VERY LITTLE PRESSURE TO CHECK FOR SECURITY, THE OIL LINE B-NUT BROKE LOOSE FROM ITS TORQUE WITH VERY LITTLE PRESSURE APPLIED. THE MX INSPECTED B-NUT OF THE OIL LINE AND THE REDUCER FITTING FOR ABNORMALITIES, NONE WERE FOUND. THE MX TORQUED THE FITTING TO APPROPRIATE SPECS IAW OEM INSTRUCTIONS. MX AGAIN APPLIED PRESSURE TO THE LINE, THE B-NUT BROKE LOOSE FROM ITS TORQUE. THESE OIL LINE B-NUTS DO NOT COME WITH MEASURES FOR INSTALLATION OF SAFETY WIRE. THE SAFETY CONCERN IS IF OTHER MAINT WAS BEING PERFORMED IN THE VICINITY OF THERE OIL LINES, MX MIGHT INADVERTENTLY CAUSE ONE OF THESE B-NUTS TO BREAK LOOSE FROM ITS TORQUE. (K)

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