Pentagon report sees delays in testing of new Boeing tanker WASHINGTON (Reuters) - A new Boeing Co aerial tanker that will refuel warplanes during flight is expected to see operational testing slip by at least 6 to 12 months, according to a U.S. Defense Department report due to be officially released on Wednesday. The $52 billion KC-46 tanker program, one of the Pentagon's biggest arms programs, calls for Boeing to deliver the first 18 of 179 new planes to the Air Force by 2017 to replace the current fleet of 50-year-old KC-135 tankers. The new report by the Pentagon's chief weapons tester, Michael Gilmore, said Boeing and the Air Force needed more time to complete developmental testing and initial training before operational testing could begin. The Pentagon is due to release Gilmore's annual report on major weapon programs Wednesday, but copies of the report began circulating in Washington on Tuesday. Gilmore's report said a detailed analysis of Boeing's initial schedules for aerial refueling certification, technical orders for aircraft and support equipment, and training pointed to a delay in operational testing of up to a year. The tanker program is one of the Pentagon's largest weapons initiatives and has been closely scrutinized since its decade-long contest with France's Airbus and an ethics scandal resulted in two Boeing officials getting sentenced to prison in 2004. The report also urged the Air Force to plan testing against realistic cybersecurity threats to identify potential vulnerabilities with the new plane, and said the program had already begun to address these concerns. No immediate comment was available from Boeing officials. Reporting by Phil Stewart and Andrea Shalal-Esa; Editing by Jeremy Laurence