B767 crew had altitude bust when then entered a cumulo nimbus on climb out.

Attributes
ACN	404611
Time
Date	199806
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bur airport : lhr
State Reference	FO
Altitude	msl bound lower : 6000 msl bound upper : 6500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lhr
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure other departure sid : sid enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	404611
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	404612
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

During the wobun 2F departure out of egll, we were flying in and around convective WX activity, cumulo nimbus cloud formations. At the time of the occurrence, we were just topping a cumulo nimbus at the same time we were attempting to level off at 6000 ft MSL. There was moderate turbulence as the captain attempted to level off the aircraft. The aircraft overshot the 6000 ft target altitude, and the captain was forced to make an aggressive correction with the throttles and pitch attitude. The aircraft at the highest point reached an altitude of 6500 ft, which is why I am writing this report. I, the PNF, advised the controller that we were deviating left of course for thunderstorms and we were able to stay clear of the WX with no further altdevs.

Original NASA ASRS Text

Title: B767 CREW HAD ALT BUST WHEN THEN ENTERED A CUMULO NIMBUS ON CLBOUT.

Narrative: DURING THE WOBUN 2F DEP OUT OF EGLL, WE WERE FLYING IN AND AROUND CONVECTIVE WX ACTIVITY, CUMULO NIMBUS CLOUD FORMATIONS. AT THE TIME OF THE OCCURRENCE, WE WERE JUST TOPPING A CUMULO NIMBUS AT THE SAME TIME WE WERE ATTEMPTING TO LEVEL OFF AT 6000 FT MSL. THERE WAS MODERATE TURB AS THE CAPT ATTEMPTED TO LEVEL OFF THE ACFT. THE ACFT OVERSHOT THE 6000 FT TARGET ALT, AND THE CAPT WAS FORCED TO MAKE AN AGGRESSIVE CORRECTION WITH THE THROTTLES AND PITCH ATTITUDE. THE ACFT AT THE HIGHEST POINT REACHED AN ALT OF 6500 FT, WHICH IS WHY I AM WRITING THIS RPT. I, THE PNF, ADVISED THE CTLR THAT WE WERE DEVIATING L OF COURSE FOR TSTMS AND WE WERE ABLE TO STAY CLR OF THE WX WITH NO FURTHER ALTDEVS.

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.