SDR 2002UALA01181

Service difficulty report · Blade · Boeing 747422

Difficulty date: July 15, 2002
Submitted: July 23, 2002
Operation: Air carrier
Aircraft: N116UA
Make and model: Boeing 747422
Aircraft serial: 26908
Aircraft time: 15,397 hours, 1,876 cycles
Engine: Pwa PW4056
System (JASC): 7250 · Turbine Section
Part: Blade
Condition: Failed
Location: Engine
Stage of operation: CL
How discovered: O
Nature of condition: G, J
Precautionary procedure: E

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

What was found

EXPERIENCED PROBLEMS W/EEC, BLEED, OIL QTY AND PRESSURE. SUPPLEMENTAL DATA UPDATE ENGINE SURGED DUE TO FAILURE OF HPT T-2 BLADE. T2 BLADE FAILURE WAS DUE TO CORROSION UNDER THE BLADE PLATFORM. RESULTANT VIBRATION FRACTURED NR 4 BEARING OIL TUBE AND EGT HARNESS CAUSING LOSS OF OIL PRESSURE AND ERRONEOUS EGT INDICATION. ENGINE WAS REMOVED FOR REFURBISHMENT AND INSTALLATION OF IMPROVED T-2 BLADES PER SB PW4ENG 72-716.