The U.S. Air Force and Boeing are embarking on an ambitious strategy to test and certify the new KC-46 aerial refueler in order to meet an aggressive fielding schedule.

The Air Force wrapped up the tanker's critical design review (CDR) early, and Boeing is now turning to manufacturing the first aircraft.

The company prevailed in a protracted duel with European Rival EADS, which offered an Airbus A330-based design, winning the contract in February 2011. Estimated to cost the Air Force $4.9 billion, it covers development of the refueler and delivery of the first 18 KC-46s by 2017. Boeing's willingness to finance some of the development cost underscores how challenging the schedule is.

The CDR, a 10-month exercise that was the first major milestone on the fixed-price, incentive-fee contract, wrapped up Aug. 21, one month ahead of plan. There were no major design changes required, according to Maj. Gen. John Thompson, Air Force program executive officer for tankers.

Out of six “critical action items” flagged during the review, he says four were paperwork issues. The remaining two involved refinement of a system that will be used by the aircraft to communicate with the Air Force's Tanker Airlift Control Center and questions about how the KC-46 will meet a requirement to operate at maximum power for 10 min. without having to undergo maintenance after landing. Both were quickly addressed and neither required major design changes, Thompson says.

The program has a 90% chance of delivering all 18 KC-46s by 2017, as required, according to an annual risk assessment performed by the Air Force, notes Thompson. At closure of the CDR, the development effort is about 40% complete.

But the biggest challenge is executing what Thompson calls the “Test Once” strategy agreed upon by Boeing, the Air Force and FAA. The goal is to maximize data collection and use by each of these communities so as not to waste time repeating test points or limiting flights to suit a single customer at a time.

The Pentagon has begun to conduct integrated developmental and operational testing on some programs to allow for data sharing to satisfy the distinct requirements of Boeing and the FAA. But the KC-46 strategy goes a step further, he says.

Work on the first test article is underway—the forward fuselage for the initial 767-2C is loaded in the jig at Boeing's 767 production line in Everrett, Wash., and Boeing has begun fabricating the first refueling boom designed specifically for the KC-46. This boom is expected to begin lab testing later this year.

First flight of the 767-2C, the commercial configuration designed specifically for the tanker and on which the KC-46 will be based, is expected by June 2014. It includes a 767-200ER baseline; main-deck cargo door and freighter features; 787-based cockpit display system; auxiliary body tanks for increased fuel carriage; and provisioning for the plumbing and wiring required for the refueling mission systems.

The tanker version is slated for first flight in January 2015. Thompson says that the wing-mounted refueling pods made by Cobham and the Boeing refueling boom are “on track” for integration onto the first-test article.

It remains to be seen just how much funding Boeing will have to contribute to the program to meet the schedule. The government estimates it will cost $5.6 billion, $500 million more than Boeing's estimate and $700 million more than the Air Force's contract ceiling, notes Thompson.

Boeing's strategy on the program has been to manage risk aggressively up front, an effort largely driven by the company's desire to limit its financial exposure to development cost. It has established multiple systems-integration laboratories—one each focused on hardware in the loop, commercial software and military-specific mission-systems testing.

But that strategy cost more management reserve funding, at a burn rate of $15 million per month, than anticipated early in the program, Air Force officials noted last year. After an internal review, Boeing restored $70 million to the management reserve fund for the program by eliminating duplications for items that had been booked in multiple cost accounts, Thompson explains. This did not amount to overcharging, but to accounting for items on the program twice. Also, the annual labor-rate adjustment fell in the government's favor last year.

Thompson says he is now “comfortable” with the status of the management reserve account, and the burn rate is about $4 million per month. The Air Force had paid $2.2 billion on the contract as of the end of June.

Meanwhile, the Air Force is finalizing its strategy to have service maintenance in place as the fleet enters operations rather than relying on protracted contractor logistics support to repair the tankers. That strategy is due in 2015, with implementation set to take place with the deliveries in 2017.