September 28, 2019: Problems continue with the new U.S. Air Force KC-46A tanker aircraft. The latest flaw doesn’t ground the aircraft but prevents it from carrying cargo and passengers. That what the “C” in KC stands for. Tanker aircraft have always had a cargo carrying capacity since the fuel for aerial refueling did not take up all the space inside the aircraft. The problem with the KC-46A is that the cargo locks on some of the cargo restraints spontaneously unlocked while in flight. There was no obvious reason so now cargo is banned until the manufacturer can fix the problem.

The KC-46A can carry 29.5 tons of cargo in up to 18 pallets. The KC-46A can also carry up to 114 passengers or 58 patients (plus medical personnel) and this is banned as well until the cargo locks are fixed. There is also a serious problem with the RVS (Remote Vision System) which uses vidcams to provide the boom operator with a better view of the refueling boom and the approaching aircraft to be refueled. The problem is that the cameras do not always provide an accurate picture of the boom and approaching aircraft. The air force is dissatisfied with how long it is taking Boeing to fix this problem. The RVS problem does not prevent refueling, just limits its efficiency.

Earlier this year the air force resumed, after a two-month delay, accepting new KC-46As. That two-month delay was because of FOD (Foreign Object Debris), including tools and other metal objects, still showing up in various parts of the aircraft. This indicated a serious lapse in the management of assembly and quality control while producing these aircraft. By March 11th, after nearly a month of effort to check out aircraft nearly ready for delivery as well as factory inspection procedures, the air force agreed to begin accepting KC-46s once more. Deliveries will continue despite the cargo lock problem but the air force is not concerned about Boeing, the manufacturer. This is the same firm that is having worse problems with its new 737 Max commercial airliner. Boeing plans to deliver 36 KC-46As by the end of 2019 and expects to meet that goal even though 19 had been delivered by early September.

FOD is a problem that can occur during the manufacture of any aircraft as well as during normal operation. Most FOD comes from small parts that come loose or are picked up by an aircraft as small objects on the airstrip that ends up in the aircraft during landing and takeoff. Nearly half of FOD incidents are because objects are sucked into the engines that cause visible or catastrophic damage. Bird strikes are the most common cause.

FOD found in newly built aircraft after delivery, or by customer inspectors during final checks at the assembly plant, indicates more serious problems with the work done at the assembly plant and how it is supervised. The problems this year began when it was noted that at the KC-46 assembly plant there were eight incidents of FOD being discovered during assembly, plus at least two that were not found and were instead discovered by air force personnel after delivery of the first six KC-46s. The led to the six KC-46s being grounded for a week while all of them were thoroughly checked for FOD. At the same time, the air force told Boeing that further KC-46 deliveries were suspended until a joint Air-Force-Boeing team could investigate work done and work practices at the Boeing plant involved. The air force has already had problems with quality control and key systems on the KC-46 that did not work as specified and had to be fixed. The first KC-46s are being used to train flight crews and maintainers so this delay is added to the two years of other delays the KC-46A has already experienced. The cargo lock problem was found as KC-46As were testing the cargo-carrying capabilities.

In January 2019 the air force was relieved to finally start receiving its long-awaited (and long overdue) new aerial tankers. Two KC-46As were delivered to an air force base in January 2019. That’s 18 years after the air force went looking for a new tanker and eight years after the KC-46A was selected. The first 18 of these was supposed to be delivered by 2017 but that was, for a while delayed until 2020. The last series of delays were caused by a component provided by Cobham, a British firm that had developed the pods that are carried under each wing to allow two aircraft to be refueled at once. These pods ran into development delays and then there were further delays waiting for British aviation authorities to approve the Cobham design in its final form. There are still some problems but not so bad that production cannot continue. By January the air force had six production model KC-45As, all delivered in January.

All these final delays were preceded by lengthy ones encountered with the competing AirBus tanker aircraft. In 2011 the competition between the American KC-767/46A and European KC-330, to replace the aging U.S. Air Force KC-135 aerial tankers, was won by Boeing's KC-767 (as the KC-46A). In 2008 the air force had selected the KC-330, but lawyers and politics upset that award and the selection process had to be repeated. Before that, the KC-767 had won the original 2002 competition, but corruption tainted that award, and the order was canceled. The 2011 award was not challenged in court. There was also a lot of resistance in the air force and Congress to any further squabbling over who should build the replacement for the KC-135.

The total value of the project, to replace the aging fleet of KC-135 and KC-10 tankers, could be as high as $44 billion. The initial order was for 18 aircraft at about $150 million each. That initial order also came with about a billion dollars for development work plus $4 billion in additional development costs that the manufacturer absorbed. The air force might order over a hundred KC-46As, but the exact number depends on what kind of future aircraft the air force will be using. If there are a lot of unmanned aircraft (UAVs), fewer tankers will be needed (because UAVs are smaller, and need less fuel).

The competition between the American (Boeing) and European (AirBus) candidates was actually quite close. The KC-330 carries 20 percent more fuel than the KC-767, plus 37 percent more cargo pallets and passengers. But this apparently worked against the KC-330, as the KC-767 is closer in size to the KC-135, and thus will not require as many new maintenance facilities. The KC-767 is also considered easier and cheaper to maintain. The KC-330/45A was to have cost about $175 million each (17 percent more than the KC-46A).

The KC-46A is based on the Boeing 767-200 airliner, which sells for about $120 million. The 767 has been in service since 1982, and over 1,100 have been manufactured so far. Boeing developed the KC-47A on its own, at a cost of nearly a billion dollars. Boeing also developed the original KC-135 tanker in the 1950s and has since built over 2,000 of these.

The two engine KC-330 (KC-45A) was based on the AirBus 330 (which costs about $160 million each). Over 1,400 330s have been produced since the aircraft entered service in 1994. Both candidates were selected for their ability to replace the four-engine KC-135. This older aircraft carries 90 tons of fuel and can transfer up to 68 tons. Typically, aerial tankers have to service B-52s (which carry over 140 tons of jet fuel) and fighters like the F-15 (over five tons). The KC-135 has long made itself useful carrying cargo and passengers, as well as fuel, and both the KC-767 and KC-30 have more capacity for this. The KC-46A can pump 1,200 gallons (4,900 liters) a minute while each of the underwing pods can deliver a third of that per minute.

With the continued delays most export sales went to the KC-330s, now called the A330 MRTT or KC-30A. So far, 50 of these have been ordered by or delivered to Australia, France, NATO, Saudi Arabia, the United Arab Emirates, Singapore, South Korea and Britain. The KC-46A has two export customers so far; Israel (8 KC-46As) and Japan (2). Several other nations are considering the KC-46A, but all these problems don’t help with turning consideration into orders.