The Air Force’s new tanker is going to be delayed again

Boeing missed a self-imposed deadline to deliver the first new KC-46 tanker to the Air Force by the end of 2017, and now the Air Force believes the company may miss its expected delivery window in spring 2018, instead presenting the first tanker late 2018, according to Aviation Week.

The Air Force came to that conclusion after a recent joint schedule risk assessment. Boeing is obligated to give the Air Force 18 of the new tankers by October 2018. Missing that deadline will likely bring additional financial penalties.

The firm has already been hit with about $2.9 billion in pretax costs under the tanker contract, which holds the planemaker responsible for costs beyond the Air Force's $4.82 billion commitment.

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Air Force spokeswoman Capt. Emily Grabowski told Aviation Week that the force will continue working with Boeing "to develop schedule mitigations" as needed and to expedite the program. "These potential delays will not result in additional program cost to the taxpayer," she added.

The tanker program has been hindered by a few persistent problems in recent months.

The most severe — a "category 1 deficiency" — is the tanker's rigid refueling boom scraping against the plane it is refueling. Such contact can compromise the special stealth coating on aircraft like the F-22 and F-35 fighters. And a tanker with a contaminated boom may also have to be grounded.

Air Force and private-sector personnel are reviewing flight data to determine the nature of such incidents and compare them to international norms, Aviation Week previously reported. That investigation will also inform a decision about replacing the remote camera used during the refueling process.

Two other issues, which have been lowered to category II, involve the tanker's high-frequency radio, which uses the skin of the aircraft broadcast and can cause sparks and fires. The Air Force wants assurances those radios will never broadcast while fuel is flowing and expects a long-term fix from Boeing. The force also expects a Boeing software update in 2018 to address the deficiency in which the refueling boom would extend on its own when disconnecting from a refueling aircraft.

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In December 2017, the FAA granted Boeing an amended type certification for the 767-2C, which is the tanker derivative of the 767 commercial plane. But the firm is yet to receive the supplemental type certification that signs off on all the military and aerial-refueling modifications that turn a 767-2C into a KC-46.

Air Force Materials Command also told Air Force Times that the tanker still needs to get the Air Force's military type certification, which will signify the safety and airworthiness of those systems and equipment.

Early 2018, a Pentagon testing and evaluation office report indicated the KC-46's most important systems — including its ability to transfer fuel — had been uninstalled or deactivated during testing under electromagnetic-pulse conditions. It recommended retesting "operationally representative" conditions.

However, the Air Force said in February 2018 it was working with the testing and evaluation office to reconcile those concerns but had no plans to change the overall tanker program or its testing timelines.

Officials from Air Force Materials Command told Air Force Times that the EMP testing was intended to evaluate mission-critical systems — like takeoff, flight, landing, aircraft control, voice communications, and use of the refueling boom and centerline drogue system.

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"The systems that were uninstalled or deactivated were not flight-critical or required for aerial refueling operations," according to the officials. After the EMP tests, they said, those critical or required systems were still operational.

The Air Force has two nuclear-threat-related tests planned for fiscal year 2018, which began in October 2017 and ends in September 2018. One will evaluate the KC-46's ability to launch and fly a safe distance from a simulated nuclear attack on its base. The other will test the tanker's "inherent nuclear hardness" to blast, radiation, flash, thermal, and EMP effects. The tests are slated for the second half of the fiscal year.

The Air Force currently plans to buy 179 of the KC-46, which is being developed to replace the Air Force's aging KC-135 fleet, the members of which are, on average, 55 years old.