B757-200
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 200; Flight Crew Total 18000; Flight Crew Type 11000
Training / Qualification; Distraction; Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action; General Maintenance Action
Aircraft; Weather
Crossing the Front Range eastbound at FL370; we encountered severe mountain wave with occasionally light wave. Our mach went from .82 to .857; about 5 KT overspeed with the overspeed warning horn on and the throttles closed. There were no hurt crewmembers or guests. The over speed lasted for about 5 seconds; later in the flight my PFD; ND and FMC screens went completely dark and got the warning beeper along with an uncommanded roll to the left of about 10 degrees. I called and discussed all with Dispatch and Maintenance. All agreed ok to continue. No further issues. I understand that there was an issue with the left AC bus.
A B757 encountered severe mountain wave activity over the Front Range at FL370 which resulted in a 5 second; 5 KT overspeed and later the Captain's PFD; ND and FMC blanked along with an uncommanded 10 degree roll. The Left AC Bus may have had a problem.