Narrative:

We were on a mission flying from ZZZ to ZZZ1. About 30 minutes into the flight we were flying at FL390 on top of a line of storms. At this time we were above the clouds in VMC; speed was approx mach. 8. We had the radar painting two small cell roughly 20 miles to our left and right. We started to experience light to medium chop for about 30 seconds and then we experienced severe turbulence. We lost approx 1;300 feet in about 3 seconds. At that point we were in IMC in continuous moderate to severe turbulence with heavy precipitation. Airspeed dropped to approx mach. 73. I then fire-walled the throttles and started climbing; directed the co-pilot to tell ATC we were experiencing severe turbulence and climbing to FL410. Once we climbed through FL393 we popped out of the clouds. At that point it was clear sky's. I then descended back to FL390 since we were now passed the storms. After the aircraft settled and was in controlled flight; I directed the boom operator to check off and to report back with the condition of the passengers in the cargo area. The boom operator reported that no one was injured; the wings had no visual damage and that he also confirmed the boom was still stowed. Total persons on board were 9; and again nobody was injured.

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Original NASA ASRS Text

Title: KC-135 Captain reported experiencing temporary loss of control due to severe turbulence.

Narrative: We were on a mission flying from ZZZ to ZZZ1. About 30 minutes into the flight we were flying at FL390 on top of a line of storms. At this time we were above the clouds in VMC; speed was approx Mach. 8. We had the radar painting two small cell roughly 20 miles to our left and right. We started to experience light to medium chop for about 30 seconds and then we experienced severe turbulence. We lost approx 1;300 feet in about 3 seconds. At that point we were in IMC in continuous moderate to severe turbulence with heavy precipitation. Airspeed dropped to approx Mach. 73. I then fire-walled the throttles and started climbing; directed the Co-pilot to tell ATC we were experiencing severe turbulence and climbing to FL410. Once we climbed through FL393 we popped out of the clouds. At that point it was clear sky's. I then descended back to FL390 since we were now passed the storms. After the aircraft settled and was in controlled flight; I directed the Boom Operator to check off and to report back with the condition of the passengers in the cargo area. The Boom Operator reported that no one was injured; the wings had no visual damage and that he also confirmed the boom was still stowed. Total persons on board were 9; and again nobody was injured.

Data retrieved from NASA's ASRS site 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.