In-flight WX encounter. Descending out of cloud layer, flight crew hit small cumulo nimbus and turbu...

Attributes
ACN	339734
Time
Date	199606
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 12000 msl bound upper : 14000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival star : star enroute airway : ztl
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 210 flight time total : 28000 flight time type : 800
ASRS Report	339734
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
Consequence	other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Inbound to atlanta from frankfurt germany, we were cleared to 14000 ft on the macey arrival. There was a cloud layer ahead that we could see was clear beneath and a few small cumulo nimbus well south of the arrival route. 14000 ft put us in this cloud layer and I requested a lower altitude to get beneath it into the clear and a smoother ride (light chop in clouds). We were cleared to 12000 ft. The base of this layer was about 12500 ft to 13000 ft, and as we came through this, we were face to face with a very small cumulo nimbus, not much wider than my wingspan and tops about 12500 ft. Too late to avoid. We encountered two moderate jolts as we passed through this then into the clear and smooth air again. There was no precipitation associated with this as we passed through it and there were no radar returns anywhere near our route. The seat belt sign had been on since about FL250 so the flight attendants could secure the cabin for landing. Unfortunately, 4 of the 13 flight attendants (the 4 who were in or near the aft galley) sustained some minor injuries. Alerted my company and had medical assistance meet us upon arrival.

Original NASA ASRS Text

Title: INFLT WX ENCOUNTER. DSNDING OUT OF CLOUD LAYER, FLC HIT SMALL CUMULO NIMBUS AND TURB WHICH RESULTED IN 4 FLT ATTENDANTS BEING INJURED.

Narrative: INBOUND TO ATLANTA FROM FRANKFURT GERMANY, WE WERE CLRED TO 14000 FT ON THE MACEY ARR. THERE WAS A CLOUD LAYER AHEAD THAT WE COULD SEE WAS CLR BENEATH AND A FEW SMALL CUMULO NIMBUS WELL S OF THE ARR RTE. 14000 FT PUT US IN THIS CLOUD LAYER AND I REQUESTED A LOWER ALT TO GET BENEATH IT INTO THE CLR AND A SMOOTHER RIDE (LIGHT CHOP IN CLOUDS). WE WERE CLRED TO 12000 FT. THE BASE OF THIS LAYER WAS ABOUT 12500 FT TO 13000 FT, AND AS WE CAME THROUGH THIS, WE WERE FACE TO FACE WITH A VERY SMALL CUMULO NIMBUS, NOT MUCH WIDER THAN MY WINGSPAN AND TOPS ABOUT 12500 FT. TOO LATE TO AVOID. WE ENCOUNTERED TWO MODERATE JOLTS AS WE PASSED THROUGH THIS THEN INTO THE CLR AND SMOOTH AIR AGAIN. THERE WAS NO PRECIPITATION ASSOCIATED WITH THIS AS WE PASSED THROUGH IT AND THERE WERE NO RADAR RETURNS ANYWHERE NEAR OUR RTE. THE SEAT BELT SIGN HAD BEEN ON SINCE ABOUT FL250 SO THE FLT ATTENDANTS COULD SECURE THE CABIN FOR LNDG. UNFORTUNATELY, 4 OF THE 13 FLT ATTENDANTS (THE 4 WHO WERE IN OR NEAR THE AFT GALLEY) SUSTAINED SOME MINOR INJURIES. ALERTED MY COMPANY AND HAD MEDICAL ASSISTANCE MEET US UPON ARR.

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.

In-flight WX encounter. Descending out of cloud layer, flight crew hit small cumulo nimbus and turbulence which resulted in 4 flight attendants being injured.