Service difficulty report · Seal · Beech 1900C

Difficulty date
December 24, 2002
Submitted
January 13, 2003
Operation
Air carrier
Aircraft
N575A
Make and model
Beech 1900C
Aircraft serial
UC83
Engine
Pwa PT6A65B
Part
Seal
Part number
1189700367
Condition
Misaligned
Location
Bulkhead
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

DURING INSPECTION OF THE RT FORWARD COWLING ASSEMBLY, IT WAS FOUND THAT THE AFT BULKHEAD HAD CRACKED AT THE LOWER MOUNT HOLES. WHEN THIS BULKHEAD IS BOLTED TO THE CORRESPONDING BULKHEAD FOR THE REAR COWLING ASSY, A SEAL INCORPORATED IN THE COWL ASSEMBLY. FLAT ACROSS THE SEAM BETWEEN BULKHEADS. IN THIS INSTANCE, HOWEVER THE SEAL HAD CURLED OVER AND BECOME TRAPPED BETWEEN THE BULKHEADS FORMING AN EMPTY SPACE APPROXIMATELY .050 BETWEEN ADJOINING SURFACES SO WHEN THE BOLTS WERE TORQUED IT SET UP LOCALIZED STRESS AT THE BOLT HOLES AND CAUSING THEM TO CRACK.

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