United Continental CEO Jeff Smisek out amid probe

United Airlines said on Tuesday that chief executive Jeff Smisek was stepping down effective immediately amid a continuing federal investigation.

The airline named CSX Chief Operating Officer Oscar Munoz as its next president and CEO.

"Jeff's departure is in connection with the company's previously disclosed investigation," board member Henry Meyer said in a conference call with analysts.

The probe involving the Port Authority of New York and New Jersey also prompted the departures of two other executives, United said. The airline said that it does not expect a financial impact from the investigation and that it will continue pursuing its existing strategic plan.