B737-300 flight crew encounters severe turbulence while en route.

Attributes
ACN	690244
Time
Date	200603
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zau.artcc
State Reference	IL
Altitude	msl single value : 24000
Environment
Flight Conditions	IMC
Weather Elements	Ice Rain Thunderstorm Turbulence Windshear
Light	Night
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 210 flight time total : 8000 flight time type : 4200
ASRS Report	690244
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 250 flight time total : 15000 flight time type : 13000
ASRS Report	690243
Events
Anomaly	inflight encounter : turbulence
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Weather
Primary Problem	Weather

Narrative:

On the way to mdw; we were deviating around level 3 and 4 thunderstorms. We asked the flight attendants to remain seated. We were in moderate turbulence for several mins. We then experienced severe turbulence for 3-5 mins. After that we were back into moderate turbulence. This lasted almost the duration of the flight. On the approach to mdw I called in-range to have maintenance meet the aircraft upon arrival due to the fact that we were in severe turbulence. The flight attendants remained seated for the rest of the flight. We had to shoot an ILS runway 31C circle-to-land runway 22L. During the severe turbulence we had +/- 50 KTS and the ivsi was +/-2000 ft. The aircraft was at minimum control. Upon arrival to mdw; maintenance met us at the gate. We discussed what had happened with them. Our flight attendants were not hurt. We talked to them and they were shaken up as anyone would have been. We had 1 more leg so we had to catch another airplane at another gate. During this flight; we neglected to contact dispatch. I feel that we were task saturated. There were no PIREPS of severe turbulence in that area. We did not expect to encounter this. None of the passenger were hurt. We did not fly into anything worse than level 2 according to the radar. I am not sure how we could have avoided this. Supplemental information from acn 690243: the turbulence got so bad that the airspeed varied about 80 KIAS. We constantly battled uncommanded 30+ degree rolls; and the aircraft was constantly climbing and descending several hundred ft.

Original NASA ASRS Text

Title: B737-300 FLT CREW ENCOUNTERS SEVERE TURB WHILE ENRTE.

Narrative: ON THE WAY TO MDW; WE WERE DEVIATING AROUND LEVEL 3 AND 4 TSTMS. WE ASKED THE FLT ATTENDANTS TO REMAIN SEATED. WE WERE IN MODERATE TURB FOR SEVERAL MINS. WE THEN EXPERIENCED SEVERE TURB FOR 3-5 MINS. AFTER THAT WE WERE BACK INTO MODERATE TURB. THIS LASTED ALMOST THE DURATION OF THE FLT. ON THE APCH TO MDW I CALLED IN-RANGE TO HAVE MAINT MEET THE ACFT UPON ARR DUE TO THE FACT THAT WE WERE IN SEVERE TURB. THE FLT ATTENDANTS REMAINED SEATED FOR THE REST OF THE FLT. WE HAD TO SHOOT AN ILS RWY 31C CIRCLE-TO-LAND RWY 22L. DURING THE SEVERE TURB WE HAD +/- 50 KTS AND THE IVSI WAS +/-2000 FT. THE ACFT WAS AT MINIMUM CTL. UPON ARR TO MDW; MAINT MET US AT THE GATE. WE DISCUSSED WHAT HAD HAPPENED WITH THEM. OUR FLT ATTENDANTS WERE NOT HURT. WE TALKED TO THEM AND THEY WERE SHAKEN UP AS ANYONE WOULD HAVE BEEN. WE HAD 1 MORE LEG SO WE HAD TO CATCH ANOTHER AIRPLANE AT ANOTHER GATE. DURING THIS FLT; WE NEGLECTED TO CONTACT DISPATCH. I FEEL THAT WE WERE TASK SATURATED. THERE WERE NO PIREPS OF SEVERE TURB IN THAT AREA. WE DID NOT EXPECT TO ENCOUNTER THIS. NONE OF THE PAX WERE HURT. WE DID NOT FLY INTO ANYTHING WORSE THAN LEVEL 2 ACCORDING TO THE RADAR. I AM NOT SURE HOW WE COULD HAVE AVOIDED THIS. SUPPLEMENTAL INFO FROM ACN 690243: THE TURB GOT SO BAD THAT THE AIRSPD VARIED ABOUT 80 KIAS. WE CONSTANTLY BATTLED UNCOMMANDED 30+ DEG ROLLS; AND THE ACFT WAS CONSTANTLY CLBING AND DSNDING SEVERAL HUNDRED FT.

Data retrieved from NASA's ASRS site as of January 2009 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.