Condor B763 over Atlantic on Mar 18th 2014, aircraft lost 4050 feet of altitude

A Condor Boeing 767-300, registration D-ABUI performing flight DE-2157 from Cancun (Mexico) to Frankfurt/Main (Germany), was enroute at FL350 near the Bahamas about two hours into the flight, when the crew observed a yellow and a number of green echo returns on the weather radar and via ACARS requested to deviate around weather. At the same time the captain illuminated the fasten seat belt signs and instructed cabin crew to stop service. The aircraft received clearance to deviate around weather as requested, requested and received clearance to climb to FL370 via ACARS. The crew subsequently initiated a shallow climb at 300 feet per minute. Climbing through FL362 the aircraft pitched down and desscended without counter reaction by the autopilot. The crew disengaged autopilot and autothrust and took manual control, arrested the descent and climbed the aircraft according to clearance. The aircraft continued to Frankfurt for a safe landing.

Germany's BFU reported in their monthly bulletin, that the flight data recorder showed the nose dropped to 18 degrees nose down, the aircraft lost 4050 feet of altitude over a period of 30 seconds, the airspeed rose from 235 KIAS to 310 KIAS in the same time. There were no injuries, the remainder of the flight was without further incident. The captain (40, ATPL, 14,049 hours total experience) was assisted by a first officer (34, ATPL, 3,134 hours total experience), a senior first officer (34, 4,650 hours total experience) complemented the crew but was not in the cockpit at the time of the occurrence. According to weather charts of the area a field of clouds with embedded isolated thunderstorm clouds between below FL100 and FL390 was visible adjacent to the aircraft's route. An investigation into the serious incident is ongoing.