Narrative:

Cruising FL330 over iowa, moderate bordering severe turbulence, circumnaving storms. Plane being tossed about severely, vertical speeds exceeding 1000 FPM up and down. Flight attendants calling cockpit, passenger getting upset and sick, first officer talking to flight attendants explaining the situation. I was climbing the aircraft to FL370 on a heading and deviating north of storm. The plane was rolling left and right in excess of 30 degrees of bank. The controller stated that I was assigned a heading to fly while in the climb and I do not refute that. I had been given clearance to proceed direct fwa when the controller told me I was supposed to remain on the assigned heading until FL370. Because of my early turn toward fwa, I was subsequently instructed to turn left because of conflicting traffic also circumnaving the storm and turbulence. I immediately complied while still attempting to control the aircraft as it was being tossed about. Eventually we cleared the area of turbulence, and were cleared direct to fwa. I apologize for the miscom and action to the controller. I was later instructed to contact center after landing in iad, and did so. If I had to experience this situation again, I would have deviated much sooner than we did had I known the turbulence was going to be so violent.

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Original NASA ASRS Text

Title: B737-500 FAILS TO FOLLOW TRACK CLRNC WHILE CIRCUMNAVING TSTMS AND ENCOUNTERING MODERATE TO SEVERE TURB.

Narrative: CRUISING FL330 OVER IOWA, MODERATE BORDERING SEVERE TURB, CIRCUMNAVING STORMS. PLANE BEING TOSSED ABOUT SEVERELY, VERT SPDS EXCEEDING 1000 FPM UP AND DOWN. FLT ATTENDANTS CALLING COCKPIT, PAX GETTING UPSET AND SICK, FO TALKING TO FLT ATTENDANTS EXPLAINING THE SIT. I WAS CLBING THE ACFT TO FL370 ON A HDG AND DEVIATING N OF STORM. THE PLANE WAS ROLLING L AND R IN EXCESS OF 30 DEGS OF BANK. THE CTLR STATED THAT I WAS ASSIGNED A HDG TO FLY WHILE IN THE CLB AND I DO NOT REFUTE THAT. I HAD BEEN GIVEN CLRNC TO PROCEED DIRECT FWA WHEN THE CTLR TOLD ME I WAS SUPPOSED TO REMAIN ON THE ASSIGNED HDG UNTIL FL370. BECAUSE OF MY EARLY TURN TOWARD FWA, I WAS SUBSEQUENTLY INSTRUCTED TO TURN L BECAUSE OF CONFLICTING TFC ALSO CIRCUMNAVING THE STORM AND TURB. I IMMEDIATELY COMPLIED WHILE STILL ATTEMPTING TO CTL THE ACFT AS IT WAS BEING TOSSED ABOUT. EVENTUALLY WE CLRED THE AREA OF TURB, AND WERE CLRED DIRECT TO FWA. I APOLOGIZE FOR THE MISCOM AND ACTION TO THE CTLR. I WAS LATER INSTRUCTED TO CONTACT CTR AFTER LNDG IN IAD, AND DID SO. IF I HAD TO EXPERIENCE THIS SIT AGAIN, I WOULD HAVE DEVIATED MUCH SOONER THAN WE DID HAD I KNOWN THE TURB WAS GOING TO BE SO VIOLENT.

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.