Air carrier large transport in-flight encounter with thunderstorm activity.

Attributes
ACN	191173
Time
Date	199110
Day	Sat
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : pxv
State Reference	IN
Altitude	msl bound lower : 34500 msl bound upper : 35000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zme tower : phl
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : j131
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 12000 flight time type : 5000
ASRS Report	191173
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : commercial pilot : cfi pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 13567 flight time type : 3368
ASRS Report	191401
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment none taken : detected after the fact
Consequence	other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Flying parallel to a front that extended from tx to canada. Radar was painting isolated thunderstorms for chicago to houston. Ceiling varied during flight but was IFR during occurrence. No cells painted on radar, but suddenly experienced severe turbulence and lighting. Lost 500 ft in seconds. Lasted approximately 30 seconds - 1 min. During this time a flight attendant was thrown to floor breaking pelvis in 2 places. Radar was on during most of flight in conjunction with TCASII (in automatic position). Believe the radar did not paint thunderstorms. Have heard of radar in conjunction with TCASII not painting tops of thunderstorms! After severe turbulence of 30 seconds - 1 min, air was once again smooth. Can only assume this was the top of a thunderstorm. Center was not painting storm nor was our radar painting anything in immediate area, although it was painting other isolated storms in the area. I think more investigation of this radar used in conjunction with TCASII is in order. Company has expressed intent to follow-up. Callback conversation with reporter revealed the following information: the comments about TCASII interference was unsubstantiated hotel lobby talk. The seat belt sign was on and the flight crew was looking for thunderstorm activity with radar tilt but got no 'return' in their immediate area. Supplemental information from acn 191401: there was no traffic in our area that could have possibly masked the cell.

Original NASA ASRS Text

Title: ACR LGT INFLT ENCOUNTER WITH TSTM ACTIVITY.

Narrative: FLYING PARALLEL TO A FRONT THAT EXTENDED FROM TX TO CANADA. RADAR WAS PAINTING ISOLATED TSTMS FOR CHICAGO TO HOUSTON. CEILING VARIED DURING FLT BUT WAS IFR DURING OCCURRENCE. NO CELLS PAINTED ON RADAR, BUT SUDDENLY EXPERIENCED SEVERE TURB AND LIGHTING. LOST 500 FT IN SECONDS. LASTED APPROX 30 SECONDS - 1 MIN. DURING THIS TIME A FLT ATTENDANT WAS THROWN TO FLOOR BREAKING PELVIS IN 2 PLACES. RADAR WAS ON DURING MOST OF FLT IN CONJUNCTION WITH TCASII (IN AUTO POS). BELIEVE THE RADAR DID NOT PAINT TSTMS. HAVE HEARD OF RADAR IN CONJUNCTION WITH TCASII NOT PAINTING TOPS OF TSTMS! AFTER SEVERE TURB OF 30 SECONDS - 1 MIN, AIR WAS ONCE AGAIN SMOOTH. CAN ONLY ASSUME THIS WAS THE TOP OF A TSTM. CENTER WAS NOT PAINTING STORM NOR WAS OUR RADAR PAINTING ANYTHING IN IMMEDIATE AREA, ALTHOUGH IT WAS PAINTING OTHER ISOLATED STORMS IN THE AREA. I THINK MORE INVESTIGATION OF THIS RADAR USED IN CONJUNCTION WITH TCASII IS IN ORDER. COMPANY HAS EXPRESSED INTENT TO FOLLOW-UP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE COMMENTS ABOUT TCASII INTERFERENCE WAS UNSUBSTANTIATED HOTEL LOBBY TALK. THE SEAT BELT SIGN WAS ON AND THE FLC WAS LOOKING FOR TSTM ACTIVITY WITH RADAR TILT BUT GOT NO 'RETURN' IN THEIR IMMEDIATE AREA. SUPPLEMENTAL INFO FROM ACN 191401: THERE WAS NO TFC IN OUR AREA THAT COULD HAVE POSSIBLY MASKED THE CELL.

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.