B737 flight crew encounters severe turbulence while at cruise altitude.

Attributes
ACN	593558
Time
Date	200309
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : clonn
State Reference	FO
Altitude	msl bound lower : 36500 msl bound upper : 37000
Environment
Flight Conditions	IMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu.artcc
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : private pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 200 flight time total : 15500 flight time type : 2000
ASRS Report	593558
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine pilot : instrument pilot : cfi pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 30 flight time total : 12400 flight time type : 1630
ASRS Report	594228
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Weather
Primary Problem	Weather

Narrative:

While cruising at FL370, we encountered severe turbulence. During this event, we lost approximately 500 ft of altitude. The aircraft was fully coupled (autoplt and autothrottles). Our WX radar was on, and indicated no WX within about 80 mi that might contain such turbulence. Supplemental information from acn 594228: the turbulence was reported to ATC and company.

Original NASA ASRS Text

Title: B737 FLT CREW ENCOUNTERS SEVERE TURB WHILE AT CRUISE ALT.

Narrative: WHILE CRUISING AT FL370, WE ENCOUNTERED SEVERE TURB. DURING THIS EVENT, WE LOST APPROX 500 FT OF ALT. THE ACFT WAS FULLY COUPLED (AUTOPLT AND AUTOTHROTTLES). OUR WX RADAR WAS ON, AND INDICATED NO WX WITHIN ABOUT 80 MI THAT MIGHT CONTAIN SUCH TURB. SUPPLEMENTAL INFO FROM ACN 594228: THE TURB WAS RPTED TO ATC AND COMPANY.

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.