Seven unfinished 767-2Cs are lined up on a remote taxiway outside Boeing’s final assembly centre in Everett, Washington. They are held in storage to await modification into a KC-46A Pegasus tanker. About 40mi south, several more completed KC-46As also sit in storage on another remote ramp adjacent to Boeing’s modification and flight centre on the outskirts of Seattle.

To Boeing, the image of stored 767-2Cs and KC-46s littering runways around the Seattle area is, while unfortunate, still re-assuring. As soon as the US Air Force allows, Boeing stands ready to rapidly deliver over a dozen stored production-standard aircraft, with a total of 32 in some stage of storage or final assembly.

For Boeing’s detractors, the same image also conjures up the long and torturous path to fielding a replacement for the over 60-year-old KC-135E tanker fleet, with the KC-46A now months behind schedule, billion of dollars over the fixed-price development contract’s $4.9 billion cost ceiling and plagued by the quirks of a new remote vision system and centreline drogue refueling system.

But Boeing wants to change the perception the programme is still in trouble. In a day-long series of tours and interviews in Everett and Seattle, Boeing executives insisted to a group of about 30 journalists that the KC-46A’s technical deficiencies are largely in the past, while offering an explanation for the awkward contrast between the company’s upbeat tone and the more pessimistic assessment of government watchdogs and top USAF procurement officials.

The KC-135E replacement programme began in November 2001, when then-senator Daniel Inouye inserted a surprise provision in an appropriations bill allowing the USAF to lease 100 tankers from Boeing. That move eventually led two years later to a scandal that landed a former top USAF acquisition official and Boeing’s chief financial officer in jail. A follow-on competition for the KC-X contract led to a contract award for the Airbus A330-based KC-45 in 2008, but that decision was overturned by the Government Accountability Office. Three years later, Boeing finally won a contract with a $4.9 billion to develop the KC-46A.

The contract called for Boeing to build four test aircraft and delivery 18 operational aircraft by August 2017, but Boeing quickly faced problems. The company reported a string of financial charges starting in 2014, with the extra costs needed to redesign the wiring and the fuel system in the KC-46A, plus address unexpected issues with the refueling boom, such as higher than expected loads and a “bow wave” effect when refueling larger aircraft.

The charges added up to more than $2.5 billion over three years. But an accounting policy change in the first quarter forced Boeing to re-state the pre-tax charges on the KC-46A to more than $3 billion, including another $81 million added in the first three months of this year.

Boeing hopes that will be the last charge on the KC-46A, but that depends on the USAF. The KC-46A’s only customer is refusing to accept the KC-46A with two “category 1” deficiencies still in effect.

First, the USAF’s operational testers complaint that the KC-46A’s long-wave infrared (LWIR)-based remote vision system (RVS) is degraded when the KC-46A casts a shadow on the refueling receptacle and when sunlight reflects off the receiving aircraft into the tanker’s cameras. Boeing believes it now has at least a temporary solution. The software for the RVS’ processors has been fine-tuned to adjust for refueling in low-light conditions. A KC-46 equipped with the enhanced software began flight tests in March. A second version of the software became available last week, Gibbons says.

Second, the KC-46A’s centreline drogue refueling hose has a design flaw that causes uncommanded disconnects under certain conditions when the receiver aircraft moves slightly too far forward or the KC-46A is flying slightly too fast, Gibbons says. “It’s a simple fix,” he adds. “It’s a tuning of the software again.” Boeing plans to start working on the software change after gathering more flight test data in certification testing later this summer, he adds.

A week-old GAO report agrees with an assessment by the USAF’s programme office that Boeing still needs months of additional flight tests to complete all 28,420 test points in the development programme.

“That is what the GAO report says,” Gibbons responds, “but we actually have one set of test points that we have to complete for first delivery. We have another set of test points for the whole programme. For the first delivery, we are 94% complete with all the test points.”

The last remaining item on Boeing’s schedule is delivering the wing aerial refueling pods. In KC-767s delivered to Japan and Italy a decade ago, the Smiths-built pods led to long delays over concerns about flutter. Boeing has eliminated those concerns on the Cobham-supplied pods for the KC-46A by clearing the entire flight envelope, says Sean Martin, Boeings chief air refueling operator. But Cobham fell behind schedule by failing to anticipate the documentation required for civil certification. Boeing now expects to begin certification flight testing with Cobham’s pods by October or November, Martin says.

Source: FlightGlobal.com