Air carrier large transport encounters severe turbulence.

Attributes
ACN	155411
Time
Date	199008
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : mdt
State Reference	PA
Altitude	msl bound lower : 23000 msl bound upper : 23000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	155411
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	inflight encounter : weather other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Weather

Narrative:

En route between rdu and roc, cruise flight. The seat belt sign was on and the F/a's were seated with their seat belts on. Rain showers were in the area. I received a heading from ATC for WX avoidance and was advised a previous aircraft had flown the prescribed route west/O incident. We had no excessive radar return and no contouring on the radar scope. Flight conditions were IFR, light rain, intermittent light chop. About 70 NM nnw of mdt we began experiencing excessive banking and pitching which I reported to ATC as severe turbulence. I requested immediate deviation and descent as the aircraft was barely ctlable. This was approved. The intensity of the turbulence remained severe intermittently for a period of about 7 mins. During this period we reversed direction of flight and landed at mdt. There were no reported injuries and the appropriate aircraft inspection was completed. I believe this incident occurred because aircraft and center radar are unable to detect wind direction changes associated with this type of turbulence. Possible solution, doppler radar.

Original NASA ASRS Text

Title: ACR LGT ENCOUNTERS SEVERE TURBULENCE.

Narrative: ENRTE BTWN RDU AND ROC, CRUISE FLT. THE SEAT BELT SIGN WAS ON AND THE F/A'S WERE SEATED WITH THEIR SEAT BELTS ON. RAIN SHOWERS WERE IN THE AREA. I RECEIVED A HDG FROM ATC FOR WX AVOIDANCE AND WAS ADVISED A PREVIOUS ACFT HAD FLOWN THE PRESCRIBED RTE W/O INCIDENT. WE HAD NO EXCESSIVE RADAR RETURN AND NO CONTOURING ON THE RADAR SCOPE. FLT CONDITIONS WERE IFR, LIGHT RAIN, INTERMITTENT LIGHT CHOP. ABOUT 70 NM NNW OF MDT WE BEGAN EXPERIENCING EXCESSIVE BANKING AND PITCHING WHICH I RPTED TO ATC AS SEVERE TURB. I REQUESTED IMMEDIATE DEVIATION AND DSNT AS THE ACFT WAS BARELY CTLABLE. THIS WAS APPROVED. THE INTENSITY OF THE TURB REMAINED SEVERE INTERMITTENTLY FOR A PERIOD OF ABOUT 7 MINS. DURING THIS PERIOD WE REVERSED DIRECTION OF FLT AND LANDED AT MDT. THERE WERE NO RPTED INJURIES AND THE APPROPRIATE ACFT INSPECTION WAS COMPLETED. I BELIEVE THIS INCIDENT OCCURRED BECAUSE ACFT AND CENTER RADAR ARE UNABLE TO DETECT WIND DIRECTION CHANGES ASSOCIATED WITH THIS TYPE OF TURB. POSSIBLE SOLUTION, DOPPLER RADAR.

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.