What was found
AIRCRAFT RETURNED TO PLATFORM AS A CONSEQUENCE OF LEFT GENERATOR FREQUENCY WITH OSCILLATION. MEL 24-1 PROCEDURE WAS APPLIED. AGAIN AIRCRAFT RETURNED TO PLATFORM AS A CONSEQUENCE OF LEFT ENGINE WAS NOT ACCELERATED. ACCELERATION CHAMBER WERE DRAINED AND LUBRICATED IAW MM 73-20-03, TESTED CORRECT. DURING OVERNIGHT SERVICE LEVEL OIL AND CHIP DETECTOR WERE VERIFIED, LEFT ENGINE SLOW ACCELERATION PROCEDURE WAS PERFORMED IAW 71-00-00 AND LEFT GENERATOR WAS TESTED IAW MM 24-10-00, ALL CORRECT. DEFERRED REPORT WAS CLOSED.