The Air Force and prime contractor Boeing [BA] completed the KC-46A Preliminary Design Review (PDR), the aerial refueling tanker’s first major milestone, on April 27, according to a service statement.

The program’s next major milestone is a Critical Design Review scheduled for the summer of 2013, it added. The CDR may determine that the tanker design is mature and ready for the manufacturing phase.

In the two-phase PDR review, the Program Executive Office reviewed plans and documentation for all aspects of the program including design, manufacturing, testing, training and sustainment, the Air Force said. The PEO determined the KC-46A meets system requirements and the PDR establishes the basis for proceeding with detailed design, it added.

Air Force Maj. Gen. Christopher Bogdan, the KC-46 program executive officer and program director, credited Boeing for the tanker program proceeding on time.

“Overall, I am pleased with the path this program is on,” Bogdan said in a statement. “We are 14 months into this major development program and Boeing has successfully met every contractual requirement on time with zero Level 1 engineering or contract changes.”

Boeing won the Air Force’s KC-X contract to replace the aging KC-135 tanker over rival European Aeronautic Defense and Space (EADS) in February 2011. The initial $3.5 billion contract is for the first 18 planes. The total program of 179 planes has a potential value of $30 billion (Defense Daily, Nov. 7).