Narrative:

While cruising at FL350, we suddenly encountered moderate to severe turbulence with very strong vertical drafts. This lasted approximately 10-20 seconds. WX conditions at the time: clear skies, lights of southern florida in clear view. No moon, very black over the water. Lightning sighted well south (around cuba) and west and southwest of miami. All several hundred mi distant. Aircraft: radar on and operating properly. We had earlier used it with perfect reception to deviate around thunderstorms going into and leaving sju. Cockpit lights normal for night flight. Visibility excellent. I suspect we hit the top of a very rapidly building, pencil-type thunderstorm. There was nothing indicated on radar and nothing visible to the eye. Totally unseen and unexpected. Actions taken: 1) south/B - north/J on. 2) called ATC advise of turbulence. Received clearance to deviate. 3) made PA. 4) got report from cabin. 5) called ATC requested direct mia and medical assistance at the gate. 6) made PA. 7) got report from cabin. 8) requested a/south deviation below 10000 ft. 9) landed without incident. Recommendations: truly I cannot recommend any actions that could be taken to avoid this occurrence in the future. Supplemental information from acn 117793: the night was very black with no moon. Just prior to the turbulence my attention was in the cockpit. The captain and I both grabbed for the yoke in order to keep control of the aircraft. There were several people injured (crew and passenger).

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Original NASA ASRS Text

Title: FLT CREW OF WDB ACFT ENCOUNTERED ISOLATED CELL OF TURBULENCE. PASSENGERS INJURED.

Narrative: WHILE CRUISING AT FL350, WE SUDDENLY ENCOUNTERED MODERATE TO SEVERE TURB WITH VERY STRONG VERTICAL DRAFTS. THIS LASTED APPROX 10-20 SECONDS. WX CONDITIONS AT THE TIME: CLEAR SKIES, LIGHTS OF SOUTHERN FLORIDA IN CLEAR VIEW. NO MOON, VERY BLACK OVER THE WATER. LIGHTNING SIGHTED WELL S (AROUND CUBA) AND W AND SW OF MIAMI. ALL SEVERAL HUNDRED MI DISTANT. ACFT: RADAR ON AND OPERATING PROPERLY. WE HAD EARLIER USED IT WITH PERFECT RECEPTION TO DEVIATE AROUND TSTMS GOING INTO AND LEAVING SJU. COCKPIT LIGHTS NORMAL FOR NIGHT FLT. VISIBILITY EXCELLENT. I SUSPECT WE HIT THE TOP OF A VERY RAPIDLY BUILDING, PENCIL-TYPE TSTM. THERE WAS NOTHING INDICATED ON RADAR AND NOTHING VISIBLE TO THE EYE. TOTALLY UNSEEN AND UNEXPECTED. ACTIONS TAKEN: 1) S/B - N/J ON. 2) CALLED ATC ADVISE OF TURBULENCE. RECEIVED CLRNC TO DEVIATE. 3) MADE PA. 4) GOT REPORT FROM CABIN. 5) CALLED ATC REQUESTED DIRECT MIA AND MEDICAL ASSISTANCE AT THE GATE. 6) MADE PA. 7) GOT REPORT FROM CABIN. 8) REQUESTED A/S DEVIATION BELOW 10000 FT. 9) LANDED WITHOUT INCIDENT. RECOMMENDATIONS: TRULY I CANNOT RECOMMEND ANY ACTIONS THAT COULD BE TAKEN TO AVOID THIS OCCURRENCE IN THE FUTURE. SUPPLEMENTAL INFORMATION FROM ACN 117793: THE NIGHT WAS VERY BLACK WITH NO MOON. JUST PRIOR TO THE TURBULENCE MY ATTN WAS IN THE COCKPIT. THE CAPT AND I BOTH GRABBED FOR THE YOKE IN ORDER TO KEEP CONTROL OF THE ACFT. THERE WERE SEVERAL PEOPLE INJURED (CREW AND PAX).

Data retrieved from NASA's ASRS site as of August 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.