Narrative:

Preflight, taxi and takeoff roll (maximum EPR selected) were normal until autothrottle engagement. At approximately 75 percent N1 captain called for autothrottles (captain flying). Target N1 EPR for takeoff was 114 percent N1. Autothrottles advanced faster than normal and set engine #1 108 percent, engine #2 114 percent, engine #3 109 percent. V1 was approximately 162 KTS. #2 egt was rising rapidly and quickly exceeded its limit of 960 degrees celsius. Power was reduced when #2 egt reached 980 degrees celsius, still rising at the captain's direction. While reducing #2 power to reduce the egt, #1 engine overtemp light illuminated. Its egt had exceeded 960 degrees celsius (engine limit) to approximately 980 degrees, still rising. At that time we had passed V1 and were approaching rotation. During rotation, engine #3 overspd warning light illuminated and engine #3 N2 indicated 114 percent (limit 110 percent). Gear retraction was called for and accomplished. All engines were rechked below minimum takeoff EPR prior to normal reduction to climb power. This allowed all engines to operate in their normal range. Maintenance iah was consulted via arinc (the flight was iah to ory) and advised of the above listed occurrence in detail. Dispatch and maintenance requested the aircraft be flown to ewr where a replacement engine was available for engine #3. The crew after a very excellent cockpit resource management discussion, dumped fuel to landing gross weight and returned to iah. It is several days after this occurrence. Last evening the captain advised me all engine instruments have been determined to have been working normally. No reason has been determined for the #3 engine N2 overspd which has multiple system to prevent this. Callback conversation with reporter revealed the following information: the #3 engine was torn down with no damage, nor identifiable problem. Engine manufacturer said it was a gauge problem and the gauge manufacturer said it was engine problem. Reporter says that his company has engine overtemps regularly and regardless of aircraft type, probably due to high temperatures associated with some of the airports where they operate. Consequently, small overtemps are not unusual and flcs become somewhat casual about them. The manufacturer's engines have what is called 'bloom and droop' which relates to expanding and contracting of turbine blades during takeoff power application. At 80 KTS the power must be set in detent or a 'clam' function may affect correct thrust output. In this case, since all engines were affected, it could have been something like this or more likely an autothrottle malfunction. The reporter's company maintenance wanted the flight crew to ferry aircraft to distant airport for engine repair, but the flight crew refused.

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Original NASA ASRS Text

Title: ACFT EQUIP PROB. ENG OVERSPD.

Narrative: PREFLT, TAXI AND TKOF ROLL (MAX EPR SELECTED) WERE NORMAL UNTIL AUTOTHROTTLE ENGAGEMENT. AT APPROX 75 PERCENT N1 CAPT CALLED FOR AUTOTHROTTLES (CAPT FLYING). TARGET N1 EPR FOR TKOF WAS 114 PERCENT N1. AUTOTHROTTLES ADVANCED FASTER THAN NORMAL AND SET ENG #1 108 PERCENT, ENG #2 114 PERCENT, ENG #3 109 PERCENT. V1 WAS APPROX 162 KTS. #2 EGT WAS RISING RAPIDLY AND QUICKLY EXCEEDED ITS LIMIT OF 960 DEGS CELSIUS. PWR WAS REDUCED WHEN #2 EGT REACHED 980 DEGS CELSIUS, STILL RISING AT THE CAPT'S DIRECTION. WHILE REDUCING #2 PWR TO REDUCE THE EGT, #1 ENG OVERTEMP LIGHT ILLUMINATED. ITS EGT HAD EXCEEDED 960 DEGS CELSIUS (ENG LIMIT) TO APPROX 980 DEGS, STILL RISING. AT THAT TIME WE HAD PASSED V1 AND WERE APCHING ROTATION. DURING ROTATION, ENG #3 OVERSPD WARNING LIGHT ILLUMINATED AND ENG #3 N2 INDICATED 114 PERCENT (LIMIT 110 PERCENT). GEAR RETRACTION WAS CALLED FOR AND ACCOMPLISHED. ALL ENGS WERE RECHKED BELOW MINIMUM TKOF EPR PRIOR TO NORMAL REDUCTION TO CLB PWR. THIS ALLOWED ALL ENGS TO OPERATE IN THEIR NORMAL RANGE. MAINT IAH WAS CONSULTED VIA ARINC (THE FLT WAS IAH TO ORY) AND ADVISED OF THE ABOVE LISTED OCCURRENCE IN DETAIL. DISPATCH AND MAINT REQUESTED THE ACFT BE FLOWN TO EWR WHERE A REPLACEMENT ENG WAS AVAILABLE FOR ENG #3. THE CREW AFTER A VERY EXCELLENT COCKPIT RESOURCE MGMNT DISCUSSION, DUMPED FUEL TO LNDG GROSS WT AND RETURNED TO IAH. IT IS SEVERAL DAYS AFTER THIS OCCURRENCE. LAST EVENING THE CAPT ADVISED ME ALL ENG INSTS HAVE BEEN DETERMINED TO HAVE BEEN WORKING NORMALLY. NO REASON HAS BEEN DETERMINED FOR THE #3 ENG N2 OVERSPD WHICH HAS MULTIPLE SYS TO PREVENT THIS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE #3 ENG WAS TORN DOWN WITH NO DAMAGE, NOR IDENTIFIABLE PROB. ENG MANUFACTURER SAID IT WAS A GAUGE PROB AND THE GAUGE MANUFACTURER SAID IT WAS ENG PROB. RPTR SAYS THAT HIS COMPANY HAS ENG OVERTEMPS REGULARLY AND REGARDLESS OF ACFT TYPE, PROBABLY DUE TO HIGH TEMPS ASSOCIATED WITH SOME OF THE ARPTS WHERE THEY OPERATE. CONSEQUENTLY, SMALL OVERTEMPS ARE NOT UNUSUAL AND FLCS BECOME SOMEWHAT CASUAL ABOUT THEM. THE MANUFACTURER'S ENGS HAVE WHAT IS CALLED 'BLOOM AND DROOP' WHICH RELATES TO EXPANDING AND CONTRACTING OF TURBINE BLADES DURING TKOF PWR APPLICATION. AT 80 KTS THE PWR MUST BE SET IN DETENT OR A 'CLAM' FUNCTION MAY AFFECT CORRECT THRUST OUTPUT. IN THIS CASE, SINCE ALL ENGS WERE AFFECTED, IT COULD HAVE BEEN SOMETHING LIKE THIS OR MORE LIKELY AN AUTOTHROTTLE MALFUNCTION. THE RPTR'S COMPANY MAINT WANTED THE FLC TO FERRY ACFT TO DISTANT ARPT FOR ENG REPAIR, BUT THE FLC REFUSED.

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.