B757-200 flight crew discovered an egt limit had been exceeded and recorded by the egt gauge sometim...

Narrative:

Shortly after level off at FL350 the first officer noted and mentioned a small white number (654) displayed under the right engine egt. No EICAS or status messages were displayed. The only reference we could find to this display was in the engine and APU systems section of the flight manual; which stated it was max egt attained. We contacted dispatch and maintenance and discussed the engine temperature and condition with the maintenance engine controller. He stated that without the airplane on the ground he would not be able to determine the length of time the engine exceeded the temperature limits and what if any further actions were necessary. By the time we completed our discussion with maintenance we were 80 NM west of ZZZ. The first officer and I decided to divert to ZZZ to further evaluate the engine. On approach to ZZZ we determined the landing weight of 200;000 pounds was over the max landing weight by 2;000 pounds. We checked the runway limit weight and performance limit weight to assure acceptable performance and we decided that landing slightly overweight was the safest course of action. On the ground maintenance reviewed the engine data and it was determined the engine was safe to operate. An overweight landing check was performed by maintenance and a short time later we departed. Engine operation was normal and within limits for the entire flight.

Original NASA ASRS Text

Title: B757-200 flight crew discovered an EGT limit had been exceeded and recorded by the EGT gauge sometime earlier in their flight. After discussing the issue with Maintenance the crew elected to divert for maintenance inspection.

Narrative: Shortly after level off at FL350 the First Officer noted and mentioned a small white number (654) displayed under the right engine EGT. No EICAS or status messages were displayed. The only reference we could find to this display was in the engine and APU systems section of the flight manual; which stated it was max EGT attained. We contacted Dispatch and Maintenance and discussed the engine temperature and condition with the Maintenance Engine Controller. He stated that without the airplane on the ground he would not be able to determine the length of time the engine exceeded the temperature limits and what if any further actions were necessary. By the time we completed our discussion with Maintenance we were 80 NM west of ZZZ. The First Officer and I decided to divert to ZZZ to further evaluate the engine. On approach to ZZZ we determined the landing weight of 200;000 LBS was over the max landing weight by 2;000 LBS. We checked the runway limit weight and performance limit weight to assure acceptable performance and we decided that landing slightly overweight was the safest course of action. On the ground Maintenance reviewed the engine data and it was determined the engine was safe to operate. An overweight landing check was performed by Maintenance and a short time later we departed. Engine operation was normal and within limits for the entire flight.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	895095
Time
Date	201006
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 22000 Flight Crew Type 1500
Person 2
Function	Pilot Not Flying First Officer
Experience	Flight Crew Last 90 Days 210 Flight Crew Total 15000 Flight Crew Type 1100
Events
Anomaly	Aircraft Equipment Problem Less Severe

B757-200 flight crew discovered an egt limit had been exceeded and recorded by the egt gauge sometime earlier in their flight. After discussing the issue with maintenance the crew elected to divert for maintenance inspection.