What was found
MAIN ROTOR BLADES FAILED TO TURN BY SPECIFIED N1 SPEED UPON STARTING ENGINE. IT WAS DETERMINED THAT SOMETHING INSIDE OF TURBINE WAS RUBBING DUE TO SOUND COMING FROM TURBINE WHEN ROTOR WAS TURNED BACKWARDS. TURBINE WAS REMOVED AND DISASSEMBLED. IT WAS FOUND THAT THE 4TH STAGE NOZZLE #4 BLADE PATH HAD DISBONDED AND WAS RUBBING THE #4 TURBINE WHEEL OUTER DIAMETER KNIFE EDGES CREATING DRAG THAT WAS CAUSING PROBLEM WITH MAIN ROTOR NOT TURNING ON START. DISBONDING WAS IN APPROXIMATELY 25 SEPARATE SPOTS SPACED AROUND CIRCUMFRENCE OF BLADE PATH, WITH THE LARGEST SPOT BEING AROUND ONE QUARTER INCH IN DIAMETER, ROUGHLY ROUND IN SHAPE AND RAISED ENOUGH TO CONTACT THE WHEEL OUTER DIAMETER. THIS CONDITION WOULD APPEAR TO B