B757 crew had an engine failure.

Attributes
ACN	437538
Time
Date	199905
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : msp.airport
State Reference	MN
Altitude	msl single value : 35000
Environment
Flight Conditions	IMC
Weather Elements	Ice Turbulence
Light	Night
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 80 flight time total : 5500 flight time type : 400
ASRS Report	437538
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport flight crew : landed in emergency condition flight crew : landed as precaution
Consequence	other
Supplementary
Problem Areas	Weather Aircraft
Primary Problem	Aircraft

Narrative:

Problem arose at cruise, FL350, light icing/light turbulence associated with cumulo nimbus. Left engine indicated N1 vibrations in 'amber' range, approximately 3.8. Initial indication was via EICAS. Captain reduced left throttle to idle, N1 vibes reduced to normal range. Increased power to cruise N1, vibrations increased to 5.0 (still in 'amber' range). Advanced throttles to climb power (in attempt to climb above ice/turbulence), N1 vibration stayed at 5.0 and left engine experienced 2 significant (rolled/yawed aircraft) compressor stalls. Also pilots detected an odor similar to burning electrical insulation. Captain elected to perform precautionary engine shutdown using engine failure/shutdown checklist and divert to msp (nearest suitable field). Landing/recovery routing, uneventful. Human factors: crew attributed vibrations to icing conditions until 'electrical smoke' odor and compressor stalls convinced pilots to shut down engine. May have been a tendency to deny any mechanical problem existed. Crew also rationalized that 'electrical smoke' odor was associated with ozone and st elmo's fire activity. Fixation on meteorological conditions probably worked against ultimate decision to shut down engine. Emergency procedures, recently practiced in single visit training simulator session, ran flawlessly. Flight attendants performed professionally.

Original NASA ASRS Text

Title: B757 CREW HAD AN ENG FAILURE.

Narrative: PROB AROSE AT CRUISE, FL350, LIGHT ICING/LIGHT TURB ASSOCIATED WITH CUMULO NIMBUS. L ENG INDICATED N1 VIBRATIONS IN 'AMBER' RANGE, APPROX 3.8. INITIAL INDICATION WAS VIA EICAS. CAPT REDUCED L THROTTLE TO IDLE, N1 VIBES REDUCED TO NORMAL RANGE. INCREASED PWR TO CRUISE N1, VIBRATIONS INCREASED TO 5.0 (STILL IN 'AMBER' RANGE). ADVANCED THROTTLES TO CLB PWR (IN ATTEMPT TO CLB ABOVE ICE/TURB), N1 VIBRATION STAYED AT 5.0 AND L ENG EXPERIENCED 2 SIGNIFICANT (ROLLED/YAWED ACFT) COMPRESSOR STALLS. ALSO PLTS DETECTED AN ODOR SIMILAR TO BURNING ELECTRICAL INSULATION. CAPT ELECTED TO PERFORM PRECAUTIONARY ENG SHUTDOWN USING ENG FAILURE/SHUTDOWN CHKLIST AND DIVERT TO MSP (NEAREST SUITABLE FIELD). LNDG/RECOVERY ROUTING, UNEVENTFUL. HUMAN FACTORS: CREW ATTRIBUTED VIBRATIONS TO ICING CONDITIONS UNTIL 'ELECTRICAL SMOKE' ODOR AND COMPRESSOR STALLS CONVINCED PLTS TO SHUT DOWN ENG. MAY HAVE BEEN A TENDENCY TO DENY ANY MECHANICAL PROB EXISTED. CREW ALSO RATIONALIZED THAT 'ELECTRICAL SMOKE' ODOR WAS ASSOCIATED WITH OZONE AND ST ELMO'S FIRE ACTIVITY. FIXATION ON METEOROLOGICAL CONDITIONS PROBABLY WORKED AGAINST ULTIMATE DECISION TO SHUT DOWN ENG. EMER PROCS, RECENTLY PRACTICED IN SINGLE VISIT TRAINING SIMULATOR SESSION, RAN FLAWLESSLY. FLT ATTENDANTS PERFORMED PROFESSIONALLY.

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