B757-200
Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Gate; Flight Crew Rejected Takeoff; General Release Refused / Aircraft Not Accepted; General Maintenance Action
Incorrect / Not Installed / Unavailable Part; Aircraft; Procedure
On our previous flight a maximum power takeoff was required due to tailwinds. During the takeoff roll with First Officer as pilot flying the right engine; although initially accelerating normally; was slow to develop full takeoff power of 1.77EPR. I manually attempted to push up the right throttle; but due to the very light fuel and passenger load the aircraft accelerated rapidly leaving little time for adjustment. Later; the First Officer and I discussed the takeoff and decided I may have not been aggressive enough in my throttle adjustment. All other engine indications and performance during the flight had been normal. The following flight again required a maximum power takeoff due to reported tailwinds and we discussed the merits of doing a standing start to ensure the right engine developed full maximum power of 1.76EPR. With a very light fuel and passenger load I decided to set power prior to brake release. During engine acceleration the right engine was slow to develop full power and when it finally did it began to rapidly fluctuate between 1.76 and 1.64EPR. I retarded the throttles; cleared the runway and returned to the gate for maintenance and fuel. Maintenance decided to placard the right Electronic Engine Control (EEC) inoperative. The subsequent takeoff attempt with autothrottles ON had similar results except the fluctuations ranged from 1.88 to 1.62EPR. I retarded the throttles and tried again with the autothrottles off with the same results. We then returned to the gate. Maintenance believed it was most likely a fuel control problem but since they did not have one available they were going to try replacing the Engine Pressure Ratio (EPR) transmitter first. Somewhat later I was asked by a manager or maintenance supervisor--he never identified himself--whether we would be willing to do an engine run after the EPR transmitter was replaced because he was unable to locate a second qualified maintenance person. I declined the engine run for the following reasons: 1. There is no established cockpit crew procedure to do a maximum power engine runup on an active runway with an open writeup and having no intention of taking off. 2. Runway XXL was closed so YYR was the only runway for takeoffs and it was very busy. 3. Maintenance had already advised me that this was most likely not the solution to the problem so I would be intentionally doing a maximum power engine run with an engine that had a known EPR overboost history with potentially disastrous results. I offered to talk to a Chief Pilot about my options. My crew and I were subsequently reassigned.
Following two aborted departures due to fluctuating EPRs on the right engine the flight crew of a B757-200 refused the aircraft when asked to perform a max thrust run-up.