Narrative:

The following incident occurred after approximately 9 hours of delay at atl. While on the ground at atl, troubleshooting was performed on the engine fire overheat system. The fire overheat control master box was changed and the engine subsequently run up. The maintenance was signed off with 'B' system fault inoperable and 'a' system okay. Air carrier maintenance and the aircraft mfr's rep determined that 'B' system fire-overheat had faulted and the aircraft was released for flight. The aircraft log book showed that the same 'B' system had been written up the previous week. At approximately XA45 EDT, the aircraft departed atl and at FL330 the no 1 engine overheat light flickered several times along with the fault light flickering and then came on steadily for some 5 second before going back off. Performed an overheat fire test with system in 'a.' system test was normal. All engine readings were normal. Continued to climb to 370. At approximately XB19 EDT in cruise and position 230 NM south of leeville on A-26, no 1 engine overheat light came on, followed by no 1 engine fire light. This was followed by alternating flashing of the fault and overheat lights. No 1 engine was retarded by the crew and the engine fire light immediately went out, with periodic flashing of the overheat and fault lights, followed by steady illuminating of fault light. With the throttle retarded, crew tested the warning system and 'a' loop would not test in fire position but tested good in overheat. Requested clearance to msy, after turning back toward msy, fault light again went out and got normal test of both overheat and fire system. Checked WX at both msy and iah. Iah was the best alternate. All warning lights had returned to normal and did not come on again. No 1 engine was checked again and all system were normal. Continued to iah west/O any further system lights blinking and had normal landing at approximately XC20 CDT.

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Original NASA ASRS Text

Title: AFTER EXTENSIVE MAINTENANCE REPAIR ON THE FIRE WARNING SYSTEM, ACFT ENCOUNTERED SAME PROBLEM AND DIVERTED BACK TO LAND.

Narrative: THE FOLLOWING INCIDENT OCCURRED AFTER APPROX 9 HRS OF DELAY AT ATL. WHILE ON THE GND AT ATL, TROUBLESHOOTING WAS PERFORMED ON THE ENGINE FIRE OVERHEAT SYS. THE FIRE OVERHEAT CTL MASTER BOX WAS CHANGED AND THE ENGINE SUBSEQUENTLY RUN UP. THE MAINT WAS SIGNED OFF WITH 'B' SYS FAULT INOPERABLE AND 'A' SYS OKAY. ACR MAINT AND THE ACFT MFR'S REP DETERMINED THAT 'B' SYS FIRE-OVERHEAT HAD FAULTED AND THE ACFT WAS RELEASED FOR FLT. THE ACFT LOG BOOK SHOWED THAT THE SAME 'B' SYS HAD BEEN WRITTEN UP THE PREVIOUS WK. AT APPROX XA45 EDT, THE ACFT DEPARTED ATL AND AT FL330 THE NO 1 ENGINE OVERHEAT LIGHT FLICKERED SEVERAL TIMES ALONG WITH THE FAULT LIGHT FLICKERING AND THEN CAME ON STEADILY FOR SOME 5 SEC BEFORE GOING BACK OFF. PERFORMED AN OVERHEAT FIRE TEST WITH SYS IN 'A.' SYS TEST WAS NORMAL. ALL ENGINE READINGS WERE NORMAL. CONTINUED TO CLB TO 370. AT APPROX XB19 EDT IN CRUISE AND POS 230 NM S OF LEEVILLE ON A-26, NO 1 ENGINE OVERHEAT LIGHT CAME ON, FOLLOWED BY NO 1 ENGINE FIRE LIGHT. THIS WAS FOLLOWED BY ALTERNATING FLASHING OF THE FAULT AND OVERHEAT LIGHTS. NO 1 ENGINE WAS RETARDED BY THE CREW AND THE ENGINE FIRE LIGHT IMMEDIATELY WENT OUT, WITH PERIODIC FLASHING OF THE OVERHEAT AND FAULT LIGHTS, FOLLOWED BY STEADY ILLUMINATING OF FAULT LIGHT. WITH THE THROTTLE RETARDED, CREW TESTED THE WARNING SYS AND 'A' LOOP WOULD NOT TEST IN FIRE POS BUT TESTED GOOD IN OVERHEAT. REQUESTED CLRNC TO MSY, AFTER TURNING BACK TOWARD MSY, FAULT LIGHT AGAIN WENT OUT AND GOT NORMAL TEST OF BOTH OVERHEAT AND FIRE SYS. CHKED WX AT BOTH MSY AND IAH. IAH WAS THE BEST ALTERNATE. ALL WARNING LIGHTS HAD RETURNED TO NORMAL AND DID NOT COME ON AGAIN. NO 1 ENGINE WAS CHKED AGAIN AND ALL SYS WERE NORMAL. CONTINUED TO IAH W/O ANY FURTHER SYS LIGHTS BLINKING AND HAD NORMAL LNDG AT APPROX XC20 CDT.

Data retrieved from NASA's ASRS site as of August 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.