Learjet 60
Flight Crew Air Transport Pilot (ATP)
Deviation - Altitude Excursion From Assigned Altitude; Ground Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Overrode Automation; Flight Crew Took Evasive Action
Weather
We were deviating to the southeast; around weather northwest of ZZZ; with the use of on board radar. We were not painting weather on the course we selected. Shortly after asking to deviate the aircraft began to climb. I turned off the autopilot and maintained wings level. Immediately thereafter we encountered numerous updrafts and downdrafts making it difficult for me to maintain altitude and airspeed. I did the best I could to maintain wings level and 'rode out' the turbulence which resulted in altitude deviations. The aircraft also banked left and right however the bank never exceeded 30 degrees in either direction. The entire encounter lasted approximately two minutes.In the future I will take on extra fuel and alter my flight plan and/or course to avoid areas of large precipitation / weather in their entirety.
We were at FL410.  We knew about the weather before we left.  There were some high top reports but not many.  We got closer to the line and asked for FL430.  We started on top but then went into IMC conditions.  We had our radar on the 100 mile range and pointed down so that the 50 mile line was painting the ground and any storms that were between 50 nm and 100 nm.  If there is a storm between the 50 nm and 100 nm and it is severe the ground behind it will not paint.  It will be black.  Also; if the storm crosses the 50 nm line and starts to disappear then you will top that storm.  We deviated to the left of course to an area that looked clear and was disappearing as we got closer.  So we should have topped it.  We got into the top of a buildup.  First Officer turned off the auto pilot and hand flew.  We got some rain and an updraft followed by a down draft and then numerous up and down drafts. we went up to 43;300 and I saw 41;800 on the down side.  The event lasted about 90 seconds.In the future; look to go-around the line or cross the line where there are lower tops.
Lear 60 flight crew reported a momentary loss of aircraft control while flying through cloud tops and encountering up- and downdrafts.