th , after nearly a month of effort (to check out aircraft nearly ready for delivery and upgrade procedures), the air force agreed to begin accepting KC-46s once more.
Two months after finally beginning to receive its new KC-46A tanker aircraft the U.S. Air Force suspended deliveries because of FOD (Foreign Object Debris), including tools and other metal objects, being found 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 11
Most FOD comes from small parts that come loose or are picked up by an aircraft from 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 KC-46 assembly plant had noted 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, the manufacturer, 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 producing the KC-46s. 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.
In January 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 is now delayed until 2020. The last series of delays was 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. The air force now has six KC-45As, all delivered in January.
All these final delays were preceded by lengthy ones encountered with the competition AirBus). 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 American 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 more cargo pallets (26 versus 19) 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 at a cost of nearly a billion dollars, on its own. 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 are replacing 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.
The KC-767 was developed partly because it is about the same size as the KC-135 (wingspan is 50.3 meters/156 feet, 6.8 percent larger than the KC-135). Thus the 767 could use the same basing and repair facilities as the 135. In the meantime, Japan and Italy have ordered eight KC-767s but with the continued delays most export sales went to the KC-330s, now called the A330 MRTT or KC-30A. So far, 60 of these have been sold to Australia, Belgium, France, Germany, Holland, Norway, Saudi Arabia, the United Arab Emirates, Singapore, South Korea and Britain.