The shock decision of Michael Armstrong, chairman of IBM World Trade and thought to be virtually unchallenged as successor to John Akers when Akers reaches retirement age in 1994, to jump ship and become chairman and chief executive of Hughes Aircraft Co throws the issue of the succession to Akers into confusion. Armstrong had inherited the poisoned chalice after all the other contenders fell from grace or by the wayside and it is now thought that Akers may have to plunge into the next generation to find his successor. According to the Wall Street Journal, the two names being mentioned are Robert Labant, who just left the AS/400 behind to become US marketing chief, and Bernard Puckett, head of software and services. Armstrong says he decided to take the top job at the General Motors Corp subsidiary because it meant he could start running his own show immediately. His mission will be to accelerate its diversification from its core military business as the peace dividend starts to bite.