Narrative:

With autoplt on, aircraft failed to level at assigned altitude of 11000'. Aircraft climbed to nearly 12000' in severe turbulence, wind shear and heavy rain. Thrust rating panel and engine thrust went to go around power, making an already bad situation even worse. Go around power was never selected by either pilot. Autothrottles were disconnected in an effort to maintain airspeed and altitude control. Flight was cleared to 13000', where ride was even worse than 11000'. Flight descended to 7000' where ride was somewhat better, but turbulence was encountered throughout entire flight lax to san. While descending through 5000' for san landing, I noticed green go around displayed above N1 indicators on upper EICAS screen. Go around was probably on both ADI's, but neither of us had noticed. I selected cruise on thrust rating panel, armed and reengaged autothrottles, and they worked normally. Callback conversation with reporter revealed the following: reporter states that the flight crew is virtually certain that they did nothing to activate the aircraft go around failure. Further the aircraft failed to stop climb when it reached the altitude set in the aircraft altitude window. The transition to go around was unnoticed for some period of time, but produced spectacular performance results. The flight crew is completely west/O theory as to how this could have happened.

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Original NASA ASRS Text

Title: ALT DEVIATION. OVERSHOOT IN CLIMB.

Narrative: WITH AUTOPLT ON, ACFT FAILED TO LEVEL AT ASSIGNED ALT OF 11000'. ACFT CLBED TO NEARLY 12000' IN SEVERE TURB, WIND SHEAR AND HEAVY RAIN. THRUST RATING PANEL AND ENG THRUST WENT TO GAR PWR, MAKING AN ALREADY BAD SITUATION EVEN WORSE. GAR PWR WAS NEVER SELECTED BY EITHER PLT. AUTOTHROTTLES WERE DISCONNECTED IN AN EFFORT TO MAINTAIN AIRSPD AND ALT CONTROL. FLT WAS CLRED TO 13000', WHERE RIDE WAS EVEN WORSE THAN 11000'. FLT DSNDED TO 7000' WHERE RIDE WAS SOMEWHAT BETTER, BUT TURB WAS ENCOUNTERED THROUGHOUT ENTIRE FLT LAX TO SAN. WHILE DSNDING THROUGH 5000' FOR SAN LNDG, I NOTICED GREEN GAR DISPLAYED ABOVE N1 INDICATORS ON UPPER EICAS SCREEN. GAR WAS PROBABLY ON BOTH ADI'S, BUT NEITHER OF US HAD NOTICED. I SELECTED CRUISE ON THRUST RATING PANEL, ARMED AND REENGAGED AUTOTHROTTLES, AND THEY WORKED NORMALLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES THAT THE FLT CREW IS VIRTUALLY CERTAIN THAT THEY DID NOTHING TO ACTIVATE THE ACFT GO AROUND FAILURE. FURTHER THE ACFT FAILED TO STOP CLB WHEN IT REACHED THE ALT SET IN THE ACFT ALT WINDOW. THE TRANSITION TO GO AROUND WAS UNNOTICED FOR SOME PERIOD OF TIME, BUT PRODUCED SPECTACULAR PERFORMANCE RESULTS. THE FLT CREW IS COMPLETELY W/O THEORY AS TO HOW THIS COULD HAVE HAPPENED.

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.