SDR 98ZZZX68

Service difficulty report · Case · Skrsky S64F

Difficulty date
December 9, 1997
Submitted
March 26, 2000
Operation
General aviation
Aircraft
N178AC
Make and model
Skrsky S64F
Aircraft serial
64097
Engine
Pwa JFTD12A5A
Part
Case
Part number
657087
Condition
Cracked
Location
Aft Flange
Part time
2,205 hours
Component
658199
Stage of operation
IN
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 INSTALLED, AFT FLANGE OF CASE SN 225 FRACTURED 360 DEGREES WITHIN THE FLANGE WELD JOINT. FRACTURING OF AFT FLANGE ASSY ELIMINATED THE AFT MOUNT FROM ENG SUPPORT. ENG FREE TO MOVE VERTICALLY, LATERALLY, AND FORE AND AFT, UNRESTRAINED BY AFT MOUNT. THIS MOTION CAUSED DAMAGE TO COMPRESSOR DIFFUSER CASE MOUNT LOCATIONS WHICH WERE DISCOVERED CRACKED SHORTLY AFTER REPLACEMENT OF FREE TURBINE ASSY. SUBMITTER STATED FAILURE OF AFT FLANGE WAS DUE TO AN IMPROPER REPAIR PERFORMED BY ANOTHER REPAIR STATION AND CONSISTED OF INCOMPLETE FUSION IN AN EB WELD, MISMATCH BETWEEN WELDED PARTS, AND UNDERCUT IN HAZ ACTING AS A STRESS RISER. DEFECTIVE BY MEANS OF IMPROPER ACCOMPLISHMENT OF APPROVED P & W REPAIR PROCESS.