The U.S. Air Force has a major problem with its new KC-46A aerial tankers; it cannot reliably refuel aircraft in a combat zone. The is because of defects in the equipment used by the boom operator to maneuver the refueling boom to connect with the aircraft being refueled so transfer of fuel could begin and complete safely, without the boom hitting and damaging the refueled aircraft.
Previous boom systems, were optically controlled as the boom operator directly observed the approaching aircraft while working from a position in the rear of the tanker, often in a prone position. The KC-46A uses a RVS (Remote Vision System) which uses vidcams providing the boom operator with views of the refueling boom and the approaching aircraft to be refueled. These cameras do not always provide accurate images 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, but does limits its efficiency and increases the risk of the boom damaging the refueled aircraft. Boeing, the designer and manufacturer of the KC-46A, has spent over five years trying to make the EVR work correctly and safely. Changes to the EVR have been so extensive that a reliable EVR will essentially be a new version, or EVR 2.0 and that is not expected to be ready until 2024 at the earliest. Until then the KC-46A cannot be used in combat zones and is still not able to handle a number of aircraft types, including the A-10C ground attack aircraft. The air force claims that the KC-46A has been tested and certified to refuel 97 percent refueling missions, based on the types of aircraft refueled each day.
The air force currently has 59 KC-46As and Boeing is delivering 90 more. After that the air force plans to buy a version of the Airbus tanker, which was originally selected to be the new tanker. Boeing appealed and got the contract. Versions of the Airbus tanker went on to operate successfully with a number of other air forces. If the air force had stuck with its original decision, reached after a competition between the two designs and evaluation of the suitability, there would be no problem. This raised questions about the air force ability to evaluate the true capabilities of new aircraft designs. By law, the air force is required to let the manufacturer take care of these problems. Usually that works but it failed with KC-46A EVR, and KC-46A in general because this aircraft was built under new management at Boeing that no longer had senior management with an engineering background. Boeing decided to become more efficient and competitive by favoring managers with a financial background and no experience in the special attention to detail and quality control required with new aircraft and especially new technologies like the EVR.
Aircraft manufacturer Boeing has lost over $5 billion so far on its contract to supply the U.S. Air Force with new KC-46A aerial tankers. The air force then agreed to help pay for additional costs of getting the EVR to work. The problems were all on Boeing and now the air force decided to proceed with their plan to order another 140 tankers, but not automatically from Boeing as would be normal. The air force is holding a competition to see who will get the follow-on contract for an existing (non-developmental) tanker. There are only two tankers that qualify; the KC-46 and the Airbus KC-30. Airbus lost the initial competition to Boeing but has been far more successful in getting its KC-30 (formerly KC-45A), now known as the MRTT (Multi-Role Tanker Transport) into production, and has already won over some tanker customers who were originally going to take whatever the Americans were using. Another irony here is that originally the KC-45A/30 was in the lead and won the initial competition. Boeing sued for a do-over and barely won that. The new competition may find Airbus as the only competitor as Boeing may decline to compete, if only to avoid more bad publicity. Boeing is lobbying Congress to stick with the Boeing KC-46A and has succeeded in delaying the switch to Airbus until Boeing runs out of time in getting the EVR fixed so that it can safely refuel all U.S. military aircraft types which use aerial refueling. The problem here that the older air force tankers (mostly KC-135Rs are rapidly being retired because they can no longer be economically, or even safely, operated. By law the air force is mandated to have 479 tankers available for potential combat operations. Until the EVR is fixed all the KC-46As can do is handle some of the training and non-combat missions. This is putting a heavier workload on the KC-135Rs. The air force proposes lowering the mandate to 455 tankers, based on the smaller number of combat aircraft (like the F-35) needed compared to the more numerous F-16s.
KC-46A finally entered service in 2019 but had not yet achieved full IOC (Initial Operating Capability) because of a number of unresolved new manufacturing and design problems. The first problem delayed the first deliveries in 2019 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. 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-46As. Deliveries continued despite a recently discovered cargo lock (unreliable cargo tie-down latches) problem. The air force was concerned about Boeing, while also needing the KC-46A as soon as possible. Boeing is the same firm that is having worse problems with its new 737 Max commercial airliner.
Once deliveries began Boeing planned to deliver 36 KC-46As by the end of 2019 and later expected to meet that goal even though only 19 had been delivered by early September. At the end of the year, the goal of 36 was missed but Boeing did fix the cargo lock problem and this allowed cargo to again be carried. There was one problem left with the accuracy of the EVR used by the 46A boom operator. That does not prevent the operation of the aircraft, it slows down refueling and sometimes can lead to damage to refueled aircraft.
In 2021 a problem was discovered involving leaky toilets. Most tankers are based on commercial freighters, with the addition of more onboard fuel and aerial refueling equipment. There is a lot of space left for passengers and cargo. The KC-46 can carry over a hundred passengers and when it does the crew toilet is not sufficient. There was already a cargo pallet based ATGL (Air Transportable Galley-Lavatory) in use with the C-17 and C-130 transports. These aircraft alternate between carrying all cargo, mixed (cargo/passenger) and all-passenger modes. Boeing, the developer of the KC-46 was told to make sure the KC-46 could easily handle the ATGL. It was a simple request for a simple task; just note the ATGL specs and their use on the other transports and the job is done. Like so many other simple design and construction tasks on the KC-46, Boeing got it wrong. They moved the orientation of the ATGL 90 degrees to fit into the KC-46 and did not note that the ATGL anti-spill valve did not work reliably in the new orientation. Boeing did not discover that until the ATGL underwent testing on the KC-46 and the leak problem became obvious. Now a new valve must be developed and tested, and there is no certainty when that will get done. Based on the many past problems with the KC-46, these avoidable problems take longer than anticipated to fix. Some problems discovered several years ago are still unresolved.
Boeing was in a hurry to deliver 179 KC-46As to the air force but the air force decided to obtain a more reliable tanker for future purchases. The total value of the project, to replace the aging fleet of KC-135 and KC-10 tankers, was potentially 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 planned on ordering over a hundred KC-46As, but the exact number depended on what kind of future aircraft the air force will be using. The air force now wants the Airbus tanker to take over and the current contract with Boeing allows that.
On paper the capabilities of the American (Boeing) and European (Airbus) tanker candidates were 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-46A 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 A330, 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 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 total while each of the underwing pods can deliver a third of that per minute.
With the continued KC-46A delays most export sales went to the Airbus tanker, now called the A330 MRTT or KC-30A. So far, over 70 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 donít help in turning consideration into orders.