Narrative:

At approximately 13000 ft in the climb; we experienced a single aircraft jolt similar to passing through an aircraft's wake turbulence. However; along with the jolt; we had an EICAS message 'det fire engine left.' the aircraft was leveled and we notified ATC of our intentions to return to ZZZZ. We declared an emergency. The det fire engine left went out after a few minutes. Along with the EICAS message; there were status messages engine eec C11; overheat circuit L1; fire loop 1 engine 1; trim air prsov right and trim air prsov left. There were no other indications. Flight attendants offered useful information about the noise they heard and that something was unusual with the left engine. I discussed with the crew whether we needed to dump fuel or whether it was better to return to landing to reduce the exposure to additional problems. I determined that it was as safe or safer to land overweight. Flight attendants were briefed as per the quick reference handbook. The weather was VFR. Touchdown was normal with less than 300 FPM sink. Left reverse was not used as a precaution. Crash fire rescue equipment advised us that there was no indicated problem with left engine. The aircraft was parked and people deplaned. Supplemental information from acn 815743: at roughly 13000 ft in the climbout; a noise was heard by cockpit crew and flight attendants. We also felt the aircraft shake as if we were in wake turbulence. Det fire engine left appeared on the EICAS screen along with numerous status messages. Declared an emergency and we returned to ZZZZ. No reverse used on left engine during landing. Taxied back to the gate. On postflight; saw damage to the aft portion of the left engine that was later determined to have been a blown bleed air line.

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Original NASA ASRS Text

Title: B777 flight crew reports engine overheat and bleed air anomalies during climb at 13000 feet and after declaring an emergency; return for an uneventful overweight landing.

Narrative: At approximately 13000 ft in the climb; we experienced a single aircraft jolt similar to passing through an aircraft's wake turbulence. However; along with the jolt; we had an EICAS message 'DET Fire Engine Left.' The aircraft was leveled and we notified ATC of our intentions to return to ZZZZ. We declared an emergency. The DET fire engine left went out after a few minutes. Along with the EICAS message; there were status messages Engine EEC C11; Overheat Circuit L1; Fire Loop 1 Engine 1; Trim Air PRSOV Right and Trim Air PRSOV Left. There were no other indications. Flight Attendants offered useful information about the noise they heard and that something was unusual with the left engine. I discussed with the crew whether we needed to dump fuel or whether it was better to return to landing to reduce the exposure to additional problems. I determined that it was as safe or safer to land overweight. Flight Attendants were briefed as per the Quick Reference Handbook. The weather was VFR. Touchdown was normal with less than 300 FPM sink. Left reverse was not used as a precaution. Crash Fire Rescue equipment advised us that there was no indicated problem with left engine. The aircraft was parked and people deplaned. Supplemental information from ACN 815743: At roughly 13000 ft in the climbout; a noise was heard by cockpit crew and Flight Attendants. We also felt the aircraft shake as if we were in wake turbulence. DET Fire Engine Left appeared on the EICAS screen along with numerous status messages. Declared an emergency and we returned to ZZZZ. No reverse used on left engine during landing. Taxied back to the gate. On postflight; saw damage to the aft portion of the left engine that was later determined to have been a blown bleed air line.

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.