B757 flight crew reported diverting to an alternate airport after noticing a high vibration level in...

Attributes
ACN	1677374
Time
Date	201908
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 180 Flight Crew Type 1032
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 200 Flight Crew Total 4984 Flight Crew Type 3554
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

While deviating north of course for thunderstorms along route at FL370 we noticed the right engine vibration indicator in the amber band and showing a value of 3.1. Flight conditions were IMC with sat -47C so engine and wing anti-ice were off. We completed the flight manual 'engine vibration' checklist and ended up reducing thrust on right engine to remove amber indication. We requested a descent to FL310 and contacted dispatch/ [maintenance] via satcom to discuss options. Per [maintenance] we turned on engine anti-ice but amber indication returned when thrust was increased. Decision was made to divert to [a nearby alternate] due to reduced thrust operation and proximity. Ran all required checklists and coordinated with ATC for clearance. Accomplished a normal ILS approach and landing. Cleared runway and accomplished normal taxi to gate.

Original NASA ASRS Text

Title: B757 flight crew reported diverting to an alternate airport after noticing a high vibration level in the right engine.

Narrative: While deviating north of course for thunderstorms along route at FL370 we noticed the right engine vibration indicator in the amber band and showing a value of 3.1. Flight conditions were IMC with SAT -47C so engine and wing anti-ice were off. We completed the Flight Manual 'Engine Vibration' checklist and ended up reducing thrust on right engine to remove amber indication. We requested a descent to FL310 and contacted Dispatch/ [Maintenance] via SATCOM to discuss options. Per [Maintenance] we turned on engine anti-ice but amber indication returned when thrust was increased. Decision was made to divert to [a nearby alternate] due to reduced thrust operation and proximity. Ran all required checklists and coordinated with ATC for clearance. Accomplished a normal ILS approach and landing. Cleared runway and accomplished normal taxi to gate.

Data retrieved from NASA's ASRS site 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.