What was found
ON TAKEOFF ROLL FROM MZT, NR 2 ENGINE VIBRATION OCCURRED ABORTED TAKEOFF AND RETURNED TO THE GATE SUBSEQUENT ENGINE CHANGE INITIATED. A LOUD BANG AND VIBRATION FROM RIGHT ENGINE OCCURRED ON TAKEOFF ROLL AT 80 KNOTS. ABORTED TAKEOFF. REPLACED ENGINE. SUBSEQUENT SHOP INVESTIGATION REVEALED TURBINE FAILURE. PRELIMINARY INDICATIONS ARE THAT A SINGEL T-4 BLADE FAILED (SEPARATED), PRECIPITATING THE FAILURE OF ALL OTHER T-4 BLADES AND THE T-4 VANES. DAMAGE ALSO PROPAGATED FORWARD TO THE T-3 BLADES AND VANES. A FAIURE ANALYSIS IS BEING CONDUCTED TO DETERMINE THE EXACT MODE OF FAILURE OF THE SINGLE T-4 BLADE. (M)