Service difficulty report · Interstage Case

Difficulty date
September 4, 1997
Submitted
March 26, 2000
Operation
General aviation
Engine
Pwa PW120
Part
Interstage Case
Part number
311755401
Condition
Corroded
Location
Rear Flange
Part time
10,040 hours
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

(CAN) THE ENGINE WAS REMOVED FROM SERVICE AFTER A ROUTINE BORESCOPE INSPECTION FOUND THE LEADING EDGES OF ALL THE PT1 TURBINE BLADES HAD DISTINCT NOTCHED AT THE VERY ROOT OF THE BLADE WITHIN THE AIRFOIL TO PLATFORM RADIUS. DISASSEMBLY FOUND THE NOTCHES IN THE PT1 TURBINE BLADE LEADING EDGES WERE CAUSED BY RUBBING CONTACT WITH THE INNER HUB OF THE PT1 STATOR. THE PT1 STATOR WAS ABLE TO MOVE REARWARD BECAUSE THE PT RETAINING BOLTS WERE ALL FRACTURED ON THE LH SIDE OF THE ENGINE, ELIMINATING ANY AXIAL RESTRAINT AT THE OUTER DIAMETER. THE STATOR WAS PUSHED REARWARD ON THE LEFT HAND SIDE OF THE ENGINE BY MASSIVE LOCALIZED SWELLING OF THE INTERSTAGE CASE REAR FLANGE CAUSED BY CORROSION.