Low altitude cloud buildup encountered in descent in IMC conditions. No WX on WX radar.

Attributes
ACN	135329
Time
Date	199001
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : csg
State Reference	GA
Altitude	msl bound lower : 16600 msl bound upper : 16600
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute airway : ztl
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 175 flight time total : 10000 flight time type : 3000
ASRS Report	135329
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	inflight encounter other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Cleared from 17,000' to 11,000'. Was solid IMC, occasional intermittent light chop only. Could not see build-ups (if any). Had radar on, 50 mi range, no WX painted even after adjusting tilt up/down. No WX painted on radar after adjusting scale up/down (100 mi, 50 mi, 25 mi). At approximately 16,600' encountered 1 big jolt that caused aircraft to 'bounce'. Turbulence was akin to someone hitting the top of the fuselage with their fist. Aircraft was not really out of control at any point. We just had that one jolt without any warning. I assessed cockpit for possible damage (there was none) and called F/a to see if she and passenger were ok. She was banged up a little (she had been serving drinks) but she was ok. She made a PA advising passenger to let her know if anybody was hurt. Nobody responded. I estimate that we had no more than -.5G forces, but it was sudden. If we had had any warning, then I most certainly would have strapped my F/a in. (Passenger had been strapped in prior to this incident -- I forgot to mention this earlier.) I have heard that sudden temperature shifts are indicative of oncoming turbulence. I didn't even get that warning. Landed without incident. A passenger reported a sore neck to ticket agents but refused medical treatment and signed a release. I wish I could have seen this coming but I don't see how I could have -- can you? To my credit, I am very restrictive with the seat belt sign and that restrictiveness probably saved someone from a serious injury. I usually have the belt sign on before we fly in any clouds.

Original NASA ASRS Text

Title: LOW ALT CLOUD BUILDUP ENCOUNTERED IN DESCENT IN IMC CONDITIONS. NO WX ON WX RADAR.

Narrative: CLRED FROM 17,000' TO 11,000'. WAS SOLID IMC, OCCASIONAL INTERMITTENT LIGHT CHOP ONLY. COULD NOT SEE BUILD-UPS (IF ANY). HAD RADAR ON, 50 MI RANGE, NO WX PAINTED EVEN AFTER ADJUSTING TILT UP/DOWN. NO WX PAINTED ON RADAR AFTER ADJUSTING SCALE UP/DOWN (100 MI, 50 MI, 25 MI). AT APPROX 16,600' ENCOUNTERED 1 BIG JOLT THAT CAUSED ACFT TO 'BOUNCE'. TURBULENCE WAS AKIN TO SOMEONE HITTING THE TOP OF THE FUSELAGE WITH THEIR FIST. ACFT WAS NOT REALLY OUT OF CONTROL AT ANY POINT. WE JUST HAD THAT ONE JOLT WITHOUT ANY WARNING. I ASSESSED COCKPIT FOR POSSIBLE DAMAGE (THERE WAS NONE) AND CALLED F/A TO SEE IF SHE AND PAX WERE OK. SHE WAS BANGED UP A LITTLE (SHE HAD BEEN SERVING DRINKS) BUT SHE WAS OK. SHE MADE A PA ADVISING PAX TO LET HER KNOW IF ANYBODY WAS HURT. NOBODY RESPONDED. I ESTIMATE THAT WE HAD NO MORE THAN -.5G FORCES, BUT IT WAS SUDDEN. IF WE HAD HAD ANY WARNING, THEN I MOST CERTAINLY WOULD HAVE STRAPPED MY F/A IN. (PAX HAD BEEN STRAPPED IN PRIOR TO THIS INCIDENT -- I FORGOT TO MENTION THIS EARLIER.) I HAVE HEARD THAT SUDDEN TEMPERATURE SHIFTS ARE INDICATIVE OF ONCOMING TURBULENCE. I DIDN'T EVEN GET THAT WARNING. LANDED WITHOUT INCIDENT. A PAX REPORTED A SORE NECK TO TICKET AGENTS BUT REFUSED MEDICAL TREATMENT AND SIGNED A RELEASE. I WISH I COULD HAVE SEEN THIS COMING BUT I DON'T SEE HOW I COULD HAVE -- CAN YOU? TO MY CREDIT, I AM VERY RESTRICTIVE WITH THE SEAT BELT SIGN AND THAT RESTRICTIVENESS PROBABLY SAVED SOMEONE FROM A SERIOUS INJURY. I USUALLY HAVE THE BELT SIGN ON BEFORE WE FLY IN ANY CLOUDS.

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.