Service difficulty report · Rib · Cessna 402B

Difficulty date
April 5, 2004
Submitted
April 7, 2004
Operation
General aviation
Aircraft
N4167G
Make and model
Cessna 402B
Aircraft serial
402B1214
Aircraft time
11,745 hours
Part
Rib
Part number
08522350
Condition
Cracked
Location
Lt Wing
Part time
11,745 hours
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

RAMP INSP FOUND OIL CANNING IN LT WING OF HIGH TIME. WING WAS INSPECTED AND ONLY DEFECT FOUND WAS LWR FLANGE ON 4 OF INTERSPAR RIBS WERE CRACKED AT STRINGER PASS-THROUGH. CRACK WAS .5-.75 INCHES LONG AND USUALLY EXTENDED PAST FIRST RIVET. AFTER REPAIRING IAW SRM THE OIL CANNING WAS STILL EVIDENT. CONCLUSION THAT OIL CANNING SKIN IS NOT RESULT OF RIB CRACKS BUT CRACKS ARE DIRECT RESULT OF OIL CANNING SKIN. OIL CANNING WHEN A GENTLE LIFTING FORCE IS PLACED ON AFT END OF TIP TANK (CAUSE OF DAMAGE) AND POSSIBLY SOME LOOSE OR SMOKING RIVETS ON RIB LINE (RESULT OF THE DAMAGE) IF RIVETS ARE LOOSE OR SMOKING BE SURE TO INSPECT INNER STRUCTURE BEFORE PUTTING A BLIND FASTENER IN.

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