Narrative:

On climbout passing through 7;000 ft; we received an advisory on ECAM left engine vib (N1) was flashing with a value of 3.8. We leveled at 10;000 ft contacted maintenance control and ran engine vibration (N1) >_ 3 units. The (N2) vibration indicated xx. All of the rest of engine indications were normal. With throttle lever movement; left engine N1 vibration continued to flash in the range of 4.0 to 3.8. We did not feel much aircraft vibration at 10;000 ft. Since the vibration indication continued to flash between 3.8 and 4.0; the length of our scheduled flight to our foreign destination; the proximity to a maintenance station; and the statement in the checklist - if engine parameters normal; continue engine operation at normal or reduced thrust level; at pilot's discretion - and that we did not know what was going on in the engine; we decided to accomplish an air turn back and leave the left engine running at reduced thrust. Considering that we were well above landing weight minimums; we would have to stay airborne for about 3 hours to burn off enough fuel to get below the minimum weight; and the abnormal ECAM engine vibration indication remained between 3.8 and 4.0; we declared an emergency and returned. We accomplished the overweight landing checklist since we were well above landing weight. We attempted to start the APU per the overweight landing checklist but it would not start and it would not start on the ground after landing. On descent; we detected airframe vibration that increased as our altitude decreased. We continued left engine operation. At touchdown our vertical speed was 200. Taxi in uneventful.

Google
 

Original NASA ASRS Text

Title: An A300 engine VIB ECAM alerted 3.8 during climb; so after troubleshooting; considering the flight time ahead and the proximity to Maintenance. The flight crew declared an emergency and returned to the departure airport.

Narrative: On climbout passing through 7;000 FT; we received an advisory on ECAM left engine VIB (N1) was flashing with a value of 3.8. We leveled at 10;000 FT contacted Maintenance Control and ran Engine Vibration (N1) >_ 3 units. The (N2) vibration indicated xx. All of the rest of engine indications were normal. With throttle lever movement; left engine N1 vibration continued to flash in the range of 4.0 to 3.8. We did not feel much aircraft vibration at 10;000 FT. Since the vibration indication continued to flash between 3.8 and 4.0; the length of our scheduled flight to our foreign destination; the proximity to a Maintenance Station; and the statement in the checklist - If engine parameters normal; continue engine operation at normal or reduced thrust level; at pilot's discretion - and that we did not know what was going on in the engine; we decided to accomplish an air turn back and leave the left engine running at reduced thrust. Considering that we were well above landing weight minimums; we would have to stay airborne for about 3 hours to burn off enough fuel to get below the minimum weight; and the abnormal ECAM engine vibration indication remained between 3.8 and 4.0; we declared an emergency and returned. We accomplished the Overweight Landing checklist since we were well above landing weight. We attempted to start the APU per the Overweight Landing checklist but it would not start and it would not start on the ground after landing. On descent; we detected airframe vibration that increased as our altitude decreased. We continued left engine operation. At touchdown our vertical speed was 200. Taxi in uneventful.

Data retrieved from NASA's ASRS site as of July 2013 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.