Lockheed Martin sacked its president and chief executive-in-waiting Christopher Kubasik Friday over an unauthorized "close personal relationship" with an employee of the company.
The company said it took the action after an ethics investigation confirmed the "improper conduct" which violated the powerful defense contractor's code of ethics.
The board of directors "asked for and received" Kubasik's resignation effective immediately, the company said in a statement.
Kubasik, 51, was replaced immediately by Marillyn Hewson, the executive vice president of Lockheed's electronic systems business area. The board announced she would also assume the post of CEO on January 1.
"While I am deeply disappointed and saddened by Chris' actions, which have been inconsistent with our values and standards, our swift response to his improper conduct demonstrates our unyielding commitment to holding every employee accountable for their actions," said chairman and outgoing chief executive Robert Stevens.
Hewson has been with Lockheed since 1983, and was already designated the next president and chief operating officer pending Kubasik's planned rise to CEO in January.
The news came shortly after the stunning but unrelated resignation Friday of famed US general David Petraeus from his position as director of the Central Intelligence Agency after he admitted having an extramarital affair with an unnamed woman.