Narrative:

I would like to report an aircraft maintenance issue that I believe should be brought to the attention of flight operations training; safety; and maintenance quality assurance. We were presented with aircraft X at ZZZ. The inbound crew commented without elaboration; 'the left engine runs a little hot.' on takeoff the left engine egt was hotter than the right. At rotation the egt showed 610 degrees. I was the PF; however; the captain elected to pull the throttle back shortly after liftoff to reduce the egt to the 590 degree limit for maximum thrust. This resulted in a substantial decrease below the takeoff EPR setting. The takeoff and reminder of the flight was uneventful and the engine operated within limits thereafter; however; egt was about 30 degrees higher than the right engine in all phases of flight. A subsequent review of all available logbook pages available; revealed this to be an ongoing problem with this engine -- in fact; there were repeated discrepancy reports dating to as early as last month. We then subsequently reported the high temperature in the logbook; along with related parameters; prior to landing at ZZZ1. As a result the airplane was removed from service and the engine changed. Here are the pertinent facts: the overlimit egt was reported in the logbook at least 4 times between last month and the date it was finally corrected by engine replacement. The corrective actions taken (bleed system repairs; egt indicator change; compressor washing) were clearly ineffective; since the discrepancy repeated. There did not appear to be any attempt by maintenance; following each repair; to use a ground power run to determine the efficiency of the repairs; or whether or not the engine produced rated thrust within limits prior to returning the airplane to service. Only 4 flight crews made discrepancy reports over the six-week period; even though there must have been many more takeoffs where the 590 limit was exceeded. The aircraft maintenance history files even showed one egt exceedance of 640 degrees; although this was not in the logbook. I do not think that a thrust reduction during the takeoff path for high egt is justified unless an engine is exceeding 630 degrees. Obstacle clearance could be in doubt if the opposite engine fails. The only germane guidance provided to flight crews in the operations manual is QRH page engine 22 and the captain was not familiar with it. The page consists of a rather ambiguous table of values; but it does suggest that engine shutdown or early landing is not justified unless the egt exceeds 645 degrees. It is my understanding that the egt and RPM limits for maximum thrust are set forth in the afm to provide a means for crews to recognize engine deterioration. This also ensures that reserve thrust can be produced within limits if required in an emergency. However; it is evident that this airplane was operated for 6 weeks or longer with an engine that could not produce rated thrust within the certificate limits. Based upon the record; neither maintenance or flight crews seemed to appreciate the significance of this. The engine might not have been capable of delivering the required thrust had the opposite engine failed. Furthermore; any use of the reverse thrust -- ARTS activation for windshear -- would have certainly caused the egt and RPM to exceed the ultimate limits. We need to have flight operations procedures and training set forth for various engine malfunctions during the takeoff path; including egt and RPM excursions; and an explanation of the purpose of the egt and RPM limits. And our maintenance qa group needs to ensure that our company is able to recognize and correct engine thrust deterioration before it results in an incident or engine failure.

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Original NASA ASRS Text

Title: AN FO REPORTS AN MD-80 WAS OPERATED FOR SIX WEEKS OR LONGER WITH A LEFT ENG THAT COULD NOT PRODUCE RATED THRUST WITHIN THE CERTIFICATE LIMITS. PILOTS NEEDED TO RETARD LEFT THROTTLE AFTER LIFTOFF TO REDUCE EGT.

Narrative: I WOULD LIKE TO REPORT AN ACFT MAINT ISSUE THAT I BELIEVE SHOULD BE BROUGHT TO THE ATTENTION OF FLT OPS TRAINING; SAFETY; AND MAINT QUALITY ASSURANCE. WE WERE PRESENTED WITH ACFT X AT ZZZ. THE INBOUND CREW COMMENTED WITHOUT ELABORATION; 'THE LEFT ENG RUNS A LITTLE HOT.' ON TKOF THE LEFT ENG EGT WAS HOTTER THAN THE RIGHT. AT ROTATION THE EGT SHOWED 610 DEGS. I WAS THE PF; HOWEVER; THE CAPT ELECTED TO PULL THE THROTTLE BACK SHORTLY AFTER LIFTOFF TO REDUCE THE EGT TO THE 590 DEG LIMIT FOR MAX THRUST. THIS RESULTED IN A SUBSTANTIAL DECREASE BELOW THE TKOF EPR SETTING. THE TKOF AND REMINDER OF THE FLT WAS UNEVENTFUL AND THE ENG OPERATED WITHIN LIMITS THEREAFTER; HOWEVER; EGT WAS ABOUT 30 DEGS HIGHER THAN THE RIGHT ENG IN ALL PHASES OF FLT. A SUBSEQUENT REVIEW OF ALL AVAILABLE LOGBOOK PAGES AVAILABLE; REVEALED THIS TO BE AN ONGOING PROBLEM WITH THIS ENG -- IN FACT; THERE WERE REPEATED DISCREPANCY REPORTS DATING TO AS EARLY AS LAST MONTH. WE THEN SUBSEQUENTLY REPORTED THE HIGH TEMP IN THE LOGBOOK; ALONG WITH RELATED PARAMETERS; PRIOR TO LNDG AT ZZZ1. AS A RESULT THE AIRPLANE WAS REMOVED FROM SVC AND THE ENG CHANGED. HERE ARE THE PERTINENT FACTS: THE OVERLIMIT EGT WAS REPORTED IN THE LOGBOOK AT LEAST 4 TIMES BETWEEN LAST MONTH AND THE DATE IT WAS FINALLY CORRECTED BY ENG REPLACEMENT. THE CORRECTIVE ACTIONS TAKEN (BLEED SYSTEM REPAIRS; EGT INDICATOR CHANGE; COMPRESSOR WASHING) WERE CLEARLY INEFFECTIVE; SINCE THE DISCREPANCY REPEATED. THERE DID NOT APPEAR TO BE ANY ATTEMPT BY MAINT; FOLLOWING EACH REPAIR; TO USE A GND POWER RUN TO DETERMINE THE EFFICIENCY OF THE REPAIRS; OR WHETHER OR NOT THE ENG PRODUCED RATED THRUST WITHIN LIMITS PRIOR TO RETURNING THE AIRPLANE TO SVC. ONLY 4 FLT CREWS MADE DISCREPANCY REPORTS OVER THE SIX-WEEK PERIOD; EVEN THOUGH THERE MUST HAVE BEEN MANY MORE TAKEOFFS WHERE THE 590 LIMIT WAS EXCEEDED. THE ACFT MAINT HISTORY FILES EVEN SHOWED ONE EGT EXCEEDANCE OF 640 DEGS; ALTHOUGH THIS WAS NOT IN THE LOGBOOK. I DO NOT THINK THAT A THRUST REDUCTION DURING THE TKOF PATH FOR HIGH EGT IS JUSTIFIED UNLESS AN ENG IS EXCEEDING 630 DEGS. OBSTACLE CLRNC COULD BE IN DOUBT IF THE OPPOSITE ENG FAILS. THE ONLY GERMANE GUIDANCE PROVIDED TO FLT CREWS IN THE OPS MANUAL IS QRH PAGE ENG 22 AND THE CAPT WAS NOT FAMILIAR WITH IT. THE PAGE CONSISTS OF A RATHER AMBIGUOUS TABLE OF VALUES; BUT IT DOES SUGGEST THAT ENG SHUTDOWN OR EARLY LNDG IS NOT JUSTIFIED UNLESS THE EGT EXCEEDS 645 DEGS. IT IS MY UNDERSTANDING THAT THE EGT AND RPM LIMITS FOR MAX THRUST ARE SET FORTH IN THE AFM TO PROVIDE A MEANS FOR CREWS TO RECOGNIZE ENG DETERIORATION. THIS ALSO ENSURES THAT RESERVE THRUST CAN BE PRODUCED WITHIN LIMITS IF REQUIRED IN AN EMER. HOWEVER; IT IS EVIDENT THAT THIS AIRPLANE WAS OPERATED FOR 6 WEEKS OR LONGER WITH AN ENG THAT COULD NOT PRODUCE RATED THRUST WITHIN THE CERTIFICATE LIMITS. BASED UPON THE RECORD; NEITHER MAINT OR FLT CREWS SEEMED TO APPRECIATE THE SIGNIFICANCE OF THIS. THE ENG MIGHT NOT HAVE BEEN CAPABLE OF DELIVERING THE REQUIRED THRUST HAD THE OPPOSITE ENG FAILED. FURTHERMORE; ANY USE OF THE REVERSE THRUST -- ARTS ACTIVATION FOR WINDSHEAR -- WOULD HAVE CERTAINLY CAUSED THE EGT AND RPM TO EXCEED THE ULTIMATE LIMITS. WE NEED TO HAVE FLT OPS PROCS AND TRAINING SET FORTH FOR VARIOUS ENG MALFUNCTIONS DURING THE TAKEOFF PATH; INCLUDING EGT AND RPM EXCURSIONS; AND AN EXPLANATION OF THE PURPOSE OF THE EGT AND RPM LIMITS. AND OUR MAINT QA GROUP NEEDS TO ENSURE THAT OUR COMPANY IS ABLE TO RECOGNIZE AND CORRECT ENG THRUST DETERIORATION BEFORE IT RESULTS IN AN INCIDENT OR ENG FAILURE.

Data retrieved from NASA's ASRS site as of May 2009 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.