B717 crew flew attitude to regain aircraft control after encountering severe convective activity.

Attributes
ACN	512690
Time
Date	200105
Day	Tue
Place
Locale Reference	navaid : atl.vortac
State Reference	GA
Altitude	msl bound lower : 10000 msl bound upper : 10500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B717 (Formerly MD-95)
Flight Phase	cruise : level
Route In Use	departure : on vectors
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 : 9200 flight time type : 450
ASRS Report	512690
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather inflight encounter other other anomaly
Resolutory Action	flight crew : regained aircraft control other
Supplementary
Problem Areas	Weather
Primary Problem	Weather

Narrative:

Leveling at 10000 ft after departing atl, we were in an area of rapidly building cumulo nimbus and tcu's. We attempted to level at 10000 ft, but thermal vertical acceleration pushed us up to 10500 ft. The aircraft was accelerating to vmo with power at idle and 4 degrees nose down attitude. Speed brakes were used to slow down and return to 10000 ft. The controller also wanted to turn us into more severe (more rapidly expanding) cumulo nimbus and tcu's but we refused to accept his vectors. We repeatedly told him 'unable due to WX' on his heading assignments. While the controller did his job very well, he commented that he 'didn't see any WX' on his radar. Our on-board radar showed light-to-moderate precipitation and a lot of vertical instability (it was in doppler/turbulence mode). As captain, I would not accept the vector into potentially dangerous atmospheric conditions. I am sorry we couldn't catch the 10000 ft leveloff, but we sure tried. We did not experience any traffic RA's on our EICAS system.

Original NASA ASRS Text

Title: B717 CREW FLEW ATTITUDE TO REGAIN ACFT CTL AFTER ENCOUNTERING SEVERE CONVECTIVE ACTIVITY.

Narrative: LEVELING AT 10000 FT AFTER DEPARTING ATL, WE WERE IN AN AREA OF RAPIDLY BUILDING CUMULO NIMBUS AND TCU'S. WE ATTEMPTED TO LEVEL AT 10000 FT, BUT THERMAL VERT ACCELERATION PUSHED US UP TO 10500 FT. THE ACFT WAS ACCELERATING TO VMO WITH PWR AT IDLE AND 4 DEGS NOSE DOWN ATTITUDE. SPD BRAKES WERE USED TO SLOW DOWN AND RETURN TO 10000 FT. THE CTLR ALSO WANTED TO TURN US INTO MORE SEVERE (MORE RAPIDLY EXPANDING) CUMULO NIMBUS AND TCU'S BUT WE REFUSED TO ACCEPT HIS VECTORS. WE REPEATEDLY TOLD HIM 'UNABLE DUE TO WX' ON HIS HDG ASSIGNMENTS. WHILE THE CTLR DID HIS JOB VERY WELL, HE COMMENTED THAT HE 'DIDN'T SEE ANY WX' ON HIS RADAR. OUR ON-BOARD RADAR SHOWED LIGHT-TO-MODERATE PRECIP AND A LOT OF VERT INSTABILITY (IT WAS IN DOPPLER/TURB MODE). AS CAPT, I WOULD NOT ACCEPT THE VECTOR INTO POTENTIALLY DANGEROUS ATMOSPHERIC CONDITIONS. I AM SORRY WE COULDN'T CATCH THE 10000 FT LEVELOFF, BUT WE SURE TRIED. WE DID NOT EXPERIENCE ANY TFC RA'S ON OUR EICAS SYS.

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.