B757 flight crew has malfunctioning left engine; declares emergency and returns to land.

Attributes
ACN	717885
Time
Date	200611
Place
Locale Reference	atc facility : zzz.tracon
State Reference	US
Altitude	msl single value : 20000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : relief pilot
ASRS Report	717885
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : eicas warning other flight crewa other flight crewb
Resolutory Action	flight crew : landed as precaution flight crew : declared emergency other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During climb through about FL190; the left engine began to vibrate. The vibration was noticeable in the cabin and registered yellow on the EICAS screen as N2. The engine power was reduced to idle. The vibration stopped. We began a return to ZZZ. The captain declared an emergency; and we returned without further incident to ZZZ.

Original NASA ASRS Text

Title: B757 FLT CREW HAS MALFUNCTIONING L ENG; DECLARES EMER AND RETURNS TO LAND.

Narrative: DURING CLB THROUGH ABOUT FL190; THE L ENG BEGAN TO VIBRATE. THE VIBRATION WAS NOTICEABLE IN THE CABIN AND REGISTERED YELLOW ON THE EICAS SCREEN AS N2. THE ENG PWR WAS REDUCED TO IDLE. THE VIBRATION STOPPED. WE BEGAN A RETURN TO ZZZ. THE CAPT DECLARED AN EMER; AND WE RETURNED WITHOUT FURTHER INCIDENT TO ZZZ.

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