Narrative:

Used autothrottles to set power for the first takeoff of the day. After the throttles checked at the 80 KT power check, noticed the EPR's were not matched. All other engine parameters were matched between engines. Tried to advance #1 EPR, but it would not respond, so aborted the takeoff at approximately 100 KTS and taxied clear of the runway. No engine malfunction was noticed and there were no EICAS caution of advisory lights. Performed an engine runup. Determined that with engine anti-ice switches on, EPR on #1 engine was low, but all other indicators were normal. With engine anti-ice switch off all readings, including EPR, were normal. After cycling the engine a/I switches we did a runup and got normal indications on both engines. After checking with our maintenance and dispatcher by radio (did not return to gate), we continued the flight we left engine a/I switches on, returned to runway 22 for takeoff. This time, again, the EPR on #1 engine was reading low and all other engine readings were normal. Continued the takeoff. In flight, after cycling the engine a/I switches, we again got normal indications at all times. My thoughts: there was nothing wrong with the engine, however something in the EICAS computer gave us erroneous readings. I question my decision to depart the airport. I felt the flight was operated safely, but don't know if it was operated legally when I continued the takeoff the second time. A write-up was made to explain the indication discrepancy.

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Original NASA ASRS Text

Title: DURING TKOF ROLL EPR GAUGE LEFT ENGINE READ LOW. CAPT ELECTED TO ABORT THE TKOF. CHECKED ENGINES. CONSULTED WITH MAINTENANCE BY RADIO AND MADE SECOND ATTEMPT. EPR STILL LOW, BUT CONTINUED TKOF. IN AIR, EPR WAS NORMAL.

Narrative: USED AUTOTHROTTLES TO SET PWR FOR THE FIRST TKOF OF THE DAY. AFTER THE THROTTLES CHKED AT THE 80 KT PWR CHK, NOTICED THE EPR'S WERE NOT MATCHED. ALL OTHER ENG PARAMETERS WERE MATCHED BTWN ENGS. TRIED TO ADVANCE #1 EPR, BUT IT WOULD NOT RESPOND, SO ABORTED THE TKOF AT APPROX 100 KTS AND TAXIED CLR OF THE RWY. NO ENG MALFUNCTION WAS NOTICED AND THERE WERE NO EICAS CAUTION OF ADVISORY LIGHTS. PERFORMED AN ENG RUNUP. DETERMINED THAT WITH ENG ANTI-ICE SWITCHES ON, EPR ON #1 ENG WAS LOW, BUT ALL OTHER INDICATORS WERE NORMAL. WITH ENG ANTI-ICE SWITCH OFF ALL READINGS, INCLUDING EPR, WERE NORMAL. AFTER CYCLING THE ENG A/I SWITCHES WE DID A RUNUP AND GOT NORMAL INDICATIONS ON BOTH ENGS. AFTER CHKING WITH OUR MAINT AND DISPATCHER BY RADIO (DID NOT RETURN TO GATE), WE CONTINUED THE FLT WE LEFT ENG A/I SWITCHES ON, RETURNED TO RWY 22 FOR TKOF. THIS TIME, AGAIN, THE EPR ON #1 ENG WAS READING LOW AND ALL OTHER ENG READINGS WERE NORMAL. CONTINUED THE TKOF. IN FLT, AFTER CYCLING THE ENG A/I SWITCHES, WE AGAIN GOT NORMAL INDICATIONS AT ALL TIMES. MY THOUGHTS: THERE WAS NOTHING WRONG WITH THE ENG, HOWEVER SOMETHING IN THE EICAS COMPUTER GAVE US ERRONEOUS READINGS. I QUESTION MY DECISION TO DEPART THE ARPT. I FELT THE FLT WAS OPERATED SAFELY, BUT DON'T KNOW IF IT WAS OPERATED LEGALLY WHEN I CONTINUED THE TKOF THE SECOND TIME. A WRITE-UP WAS MADE TO EXPLAIN THE INDICATION DISCREPANCY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.