An air taxi jet ballooned while transitioning from climb to level flight after entering a cumulus.

Attributes
ACN	311700
Time
Date	199507
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : fak
State Reference	VA
Altitude	msl bound lower : 15000 msl bound upper : 15300
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : ord
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 135
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : atp
Experience	flight time last 90 days : 85 flight time total : 18000 flight time type : 55
ASRS Report	311700
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 30 flight time total : 4300 flight time type : 100
ASRS Report	311699
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were cleared to 15000 ft by center, and were climbing through 14800 ft when the aircraft entered a cumulus build up. We had tried to avoid the cloud by getting a deviation from center, but the frequency was congested, so we were not able to get clearance to deviate. The cloud didn't look too bad and we thought we could enter it with no problem. As we attempted to level off, the cloud's updraft caused us to balloon to about 15300 ft. Shortly thereafter, the controller asked us to verify our altitude. The captain told the controller we were attempting to maintain 15000 ft. The controller called traffic at 12 O'clock 1000 ft above. We never saw the traffic and apparently no serious conflict existed.

Original NASA ASRS Text

Title: AN AIR TAXI JET BALLOONED WHILE TRANSITIONING FROM CLB TO LEVEL FLT AFTER ENTERING A CUMULUS.

Narrative: WE WERE CLRED TO 15000 FT BY CTR, AND WERE CLBING THROUGH 14800 FT WHEN THE ACFT ENTERED A CUMULUS BUILD UP. WE HAD TRIED TO AVOID THE CLOUD BY GETTING A DEV FROM CTR, BUT THE FREQ WAS CONGESTED, SO WE WERE NOT ABLE TO GET CLRNC TO DEVIATE. THE CLOUD DIDN'T LOOK TOO BAD AND WE THOUGHT WE COULD ENTER IT WITH NO PROB. AS WE ATTEMPTED TO LEVEL OFF, THE CLOUD'S UPDRAFT CAUSED US TO BALLOON TO ABOUT 15300 FT. SHORTLY THEREAFTER, THE CTLR ASKED US TO VERIFY OUR ALT. THE CAPT TOLD THE CTLR WE WERE ATTEMPTING TO MAINTAIN 15000 FT. THE CTLR CALLED TFC AT 12 O'CLOCK 1000 FT ABOVE. WE NEVER SAW THE TFC AND APPARENTLY NO SERIOUS CONFLICT EXISTED.

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.