Boeing has confirmed new details about the new 767-2C commercial freighter that has been revealed as the core of the KC-46A, but key aspects of the aircraft's configuration remain undisclosed more than three months after the award of the US Air Force's KC-X tanker contract.
Boeing describes the 767-2C as a "minor" variation of the 767-200ER platform, but it is clear that the company has made significant changes. The maximum take-off weight is increased by 9,070kg (20,000lb) to just over 188,000kg, making the freighter version of the -200ER model even heavier than the 767-300ER. The length of the -200ER is also increased by 2m (6.5ft) to 50.5m for the KC-46A.
The 767-2C configuration also includes a cargo floor and door, a 787-based large display system, auxiliary fuel tanks and provisions for tanker systems, such as hose and drogue and boom refuelling systems, Boeing said.
It remains unclear, however, if Boeing has made any other changes from the basic design of the 767-200ER platform.
These details will remain undisclosed until Boeing completes a system requirements review and an integrated baseline review with the air force, said Jean Chamberlin, vice-president and general manager of Boeing's military division.
But the disclosure still provides the most complete picture of the aircraft released by Boeing to date.
Company officials declined multiple requests during the 16-month bidding process to disclose the identity of the aircraft configuration contained in its proposal.
It previously had offered the 767-200LRF composite airframe, mating the fuselage of the 767-200ER and the wings of the 767-300ER. That proposal initially lost to a bid from a Northrop Grumman/EADS North America team offering the Airbus A330-200-based KC-45, but the victory was overturned by the US Government Accountability Office after Boeing protested over the air force's evaluation process.
Boeing took a different approach in the follow-up competition by keeping certain details about its offering a closely guarded secret.
The existence of the 767-2C marks the latest commercial freighter variant in Boeing's product line-up, but it was not immediately clear if the airframe would be offered to the civil cargo market.
Each 767-2C will be assembled in Everett, Washington, then moved to Wichita in Kansas to install military avionics and refuelling systems for the KC-46A.
It was also clear from previously released images that the KC-46A incorporated a 777-style cursor control unit. Contract documents obtained from the USAF also reveal the airframe incorporates a central maintenance computer.
The 767-2C also introduces a new engine option for the 767-200ER variant with the 62,000lb-thrust (275kN) Pratt & Whitney 4062 turbofan. The model was previously supported by PW4052/4056/4060-series engines and the General Electric CF6-80C2 series.