As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GE DIAGNOSTICS REPORTS NR 1 ENGINE TREND DATA SHOWS A SUDDEN DECREASE IN CRUISE DELTA EGT WITH A CORRESPONDING INCREASE IN TAKEOFF HOT DAY MARGIN. INDICATION ERRORS ARE SUSPECT. LONG TERM FAULT 77 10841 TOP RIGHT EGT SIGNAL OUT OF RANGE NR 1 ENG. ACCOMPLISHED TSR 904861 WO 44572 TC 78273000, ACCOMPLISHED CLEANED EGT CONNECTORS REF MM 77-21-00 NO HELP. REPLACED S1 EGT PROBE REF MM 77-21-01 NO HELP. PERFORMED EEC BITE TEST FOR ENG 1 CHA + CHB NO RECENT FAULTS AND NO RECORDED FAULTS LOGGED.