What was found
DURING TAKEOFF FROM POS, THE RIGHT ENGINE EXPERIENCED A LOSS OF TORQUE AND THE TAKEOFF WAS ABORTED. A STATIC RUN UP WAS COMPLIED WITH FOR BOTH ENGINES AND WAS SATISFACTORY. THE CAPTAIN ATTEMPTED A SECOND TAKEOFF, THE LOSS OF TORQUE WAS EXPERIENCED AGAIN AND THE SECOND TAKEOFF ABORTED. MAINTENANCE REMOVED AND REPLACED THE RIGHT TORQUE LIMITER-BY-PASS VALVE WITH AN OVERHAULED UNIT. THE GROUND POWER AND LEAK CHECKS WERE SATISFACTORY. AIRCRAFT WAS RETURNED TO SERVICE. (M)