MD-82
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff
Aircraft; Procedure
I was the pilot flying. We performed a max power takeoff due to a slight tail wind component. After a power check at 1.4 EPR that was normal; autothrottle was selected and power increased to 2.04 EPR. At the 80 KT airspeed check; I glanced at the engine instruments and saw the left EPR was a bit low and the right a bit high; I modulated the throttles very slightly to match; N1's and N2's were normal and matched left/right. At about 110 KTS; with my fingers on the reversers; I glanced at the EPR's again because I felt a throttle split under my arm. They were still at about 2.04 EPR; but the split was about 1 knob. The throttle split caused me to re-check the N1's; N2's and EGT's.  The right N1 had decreased to about 4-5% less than the left. With the speed at about 115 KTS I scanned EPR's again; then the N1's again. The N1 on the right engine had now dropped to about 9-10% less than the left: estimated at 88% left and 78% right; left EGT was about 575 and the right about 550. Both EPR's remained at 2.04. I initiated a rejected take off at 120 KTS and the First Officer advised Tower.  I taxied clear of the runway and briefed the flight attendants and passengers.
[Narrative contains no additional information].
MD-82 Captain rejected takeoff at 120 KTS due to 10% less N1 and 25 degrees lower EGT on right engine than left engine. EPR's were matched at 2.04. Successful reject with no issues other than required brake cooling.