Narrative:

Location: derok, mid pacific. On course, on altitude, FL330 near derok. Encountered increasing turbulence from moderate to severe. Requested lower altitude 4 times over 20 mins. Told unable due to traffic. Decided to turn off track and parallel at 10 mi and descend to FL315 where turbulence abated. Sfo asked our position and cleared us to offset 60 mi north of track then cleared to FL310 and reclred onto track. Asked if deviation was due to emergency condition. We said, 'yes due to severe turbulence.'

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Original NASA ASRS Text

Title: B757 OPERATING IN CLASS TWO AIRSPACE OVER THE PACIFIC ENCOUNTERED SEVERE TURB, UTILIZED EMER AUTH TO OFFSET FROM COURSE AND DSND.

Narrative: LOCATION: DEROK, MID PACIFIC. ON COURSE, ON ALT, FL330 NEAR DEROK. ENCOUNTERED INCREASING TURB FROM MODERATE TO SEVERE. REQUESTED LOWER ALT 4 TIMES OVER 20 MINS. TOLD UNABLE DUE TO TFC. DECIDED TO TURN OFF TRACK AND PARALLEL AT 10 MI AND DSND TO FL315 WHERE TURB ABATED. SFO ASKED OUR POS AND CLRED US TO OFFSET 60 MI N OF TRACK THEN CLRED TO FL310 AND RECLRED ONTO TRACK. ASKED IF DEV WAS DUE TO EMER CONDITION. WE SAID, 'YES DUE TO SEVERE TURB.'

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.