The first of four Boeing KC-46A engineering, manufacturing and development (EMD) aircraft made its first flight from Paine Field, Everett, Washington, on Dec. 28, starting the clock ticking toward the planned delivery of the first 18 new 767-based tankers to the U.S. Air Force by August 2017.

EMD-1, also known as VH001, took off under overcast skies at 9:29 a.m. (PST) and landed 3 hr., 32 min. later at Boeing Field, Seattle, where initial flight tests will be based. The first KC-46A test aircraft is a specially developed 767-2C commercial freighter variant which does not yet have any aerial refueling system or other military systems.

"The 767-2C performed flawlessly on its initial flight today – no surprises," says Ron Johnston, Boeing Test & Evaluation KC-46A program test pilot. "We took it to 28,000 feet and near max speed, verified aircraft handling characteristics and most of the systems."

Despite major installation issues with wiring that delayed the first flight of the 767-2C by six months, and which have also put back the start of flight tests of the follow-on, first fully-configured KC-46A to April 2015, Boeing says it is confident all three remaining test aircraft will be "up in the air in 2015." The company adds that "it remains on plan to deliver the initial 18 combat-ready KC-46A tankers to the Air Force by 2017."

Under the tanker contract awarded in 2011, Boeing will use the four test aircraft as part of a combined effort to earn two separate certifications from the FAA, the first of which will be an amended type certificate for a 767-2C "provisioned freighter" without the aerial refueling system and associated military avionics planned for the tanker. Boeing will then apply for a supplemental type certificate (STC) for the fully equipped KC-46A version, which will also receive standard military certification. VH004 (EMD 2), the second aircraft due to join the flight test effort, will be the first KC-46A.

Earlier this month, the Air Force said any delay to this first KC-46A flight past April could jeopardize the schedule for a milestone C low-rate initial production decision expected in September. But if this is approved, it will clear the way for the first two low-rate lots of seven and 12 aircraft.

Based on the 767-200ER baseline fuselage design, the -2C includes a strengthened main-deck cargo floor, cargo door and freighter features, strengthened 767-300ER wings, 767-400ER horizontal stabilizers, 787-based cockpit display system, auxiliary body tanks for increased fuel capacity and provisioning for the plumbing and wiring required for the refueling mission systems.

Following airframe assembly on the standard 767 line in Everett’s Building 40-32, mission systems will be installed at a separate "in-line" production site at the south end of Paine Field. The process, which will take place in the Everett Modification Center (EMC) created to refurbish early-build, out-of-specification 787 airliners, is similar to the procedure adopted for completion of the 737-based P-8 maritime patrol variant at Boeing Field. The tanker program headquarters is also moving from a nearby site in Mukilteo to the EMC to co-locate engineers and managers with the aircraft during the finishing process.