A B737-300 encounters clear air turbulence climbing through FL300. Flight crew believes it came from a wake turbulence encounter from a preceding DC10, 9 mi ahead at FL310.

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Attributes
ACN	410316
Time
Date	199808
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pit
State Reference	PA
Altitude	msl bound lower : 30000 msl bound upper : 30000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 14800 flight time type : 5000
ASRS Report	410316
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 5000
ASRS Report	410317
Events
Anomaly	inflight encounter other other anomaly other anomaly other
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	flight crew : declared emergency flight crew : exited adverse environment flight crew : regained aircraft control other
Consequence	other
Miss Distance	horizontal : 54000 vertical : 1000
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

In smooth air during climb out to our cruise altitude of FL310 as we were passing FL300 encountered light to moderate chop (wake turbulence?) immediately followed by excessive roll/yaw. Autoplt and autothrottles were disconnected and control of the aircraft was regained. Numerous injuries in cabin. Diverted to pit, made an overweight landing. EMS personnel met the flight and attended to injured crew and passenger. If this was a wake turbulence event (what I presently suspect) was center spacing behind the wake turbulence producing aircraft adequate. Does it need to be lengthened. Supplemental information from acn 410317: in climb to cruise altitude, we had a nice, smooth ride with reports of smooth rides ahead. Climbing through FL300 we encountered about 5-10 seconds of severe turbulence followed by a smooth ride again. Flight attendant advised we had injuries so we declared an emergency and diverted into pit. Supplemental information from acn 410579: aircraft #1 was climbing out of FL290 for FL310. Aircraft #1 reported hitting severe turbulence. Aircraft #1 had to make emergency diversion and land at another airport. Believe aircraft #1 encountered wake turbulence from aircraft #2 approximately 9 mi in front, level at FL310.

Original NASA ASRS Text

Title: A B737-300 ENCOUNTERS CLR AIR TURB CLBING THROUGH FL300. FLC BELIEVES IT CAME FROM A WAKE TURB ENCOUNTER FROM A PRECEDING DC10, 9 MI AHEAD AT FL310.

Narrative: IN SMOOTH AIR DURING CLBOUT TO OUR CRUISE ALT OF FL310 AS WE WERE PASSING FL300 ENCOUNTERED LIGHT TO MODERATE CHOP (WAKE TURB?) IMMEDIATELY FOLLOWED BY EXCESSIVE ROLL/YAW. AUTOPLT AND AUTOTHROTTLES WERE DISCONNECTED AND CTL OF THE ACFT WAS REGAINED. NUMEROUS INJURIES IN CABIN. DIVERTED TO PIT, MADE AN OVERWT LNDG. EMS PERSONNEL MET THE FLT AND ATTENDED TO INJURED CREW AND PAX. IF THIS WAS A WAKE TURB EVENT (WHAT I PRESENTLY SUSPECT) WAS CTR SPACING BEHIND THE WAKE TURB PRODUCING ACFT ADEQUATE. DOES IT NEED TO BE LENGTHENED. SUPPLEMENTAL INFO FROM ACN 410317: IN CLB TO CRUISE ALT, WE HAD A NICE, SMOOTH RIDE WITH RPTS OF SMOOTH RIDES AHEAD. CLBING THROUGH FL300 WE ENCOUNTERED ABOUT 5-10 SECONDS OF SEVERE TURB FOLLOWED BY A SMOOTH RIDE AGAIN. FLT ATTENDANT ADVISED WE HAD INJURIES SO WE DECLARED AN EMER AND DIVERTED INTO PIT. SUPPLEMENTAL INFO FROM ACN 410579: ACFT #1 WAS CLBING OUT OF FL290 FOR FL310. ACFT #1 RPTED HITTING SEVERE TURB. ACFT #1 HAD TO MAKE EMER DIVERSION AND LAND AT ANOTHER ARPT. BELIEVE ACFT #1 ENCOUNTERED WAKE TURB FROM ACFT #2 APPROX 9 MI IN FRONT, LEVEL AT FL310.

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.