Boeing KC-46 Pegasus

In 2001, the U.S. Air Force began a procurement program to replace around 100 of its oldest KC-135E Stratotankers, and selected Boeing's KC-767. The Boeing tanker received the KC-767A designation from the United States Department of Defense in 2002 and appeared in the 2004 edition of DoD model designation report.[2] The Air Force decided to lease 100 KC-767 tankers from Boeing.[3]

US Senator John McCain and others criticized the draft leasing agreement as being wasteful and problematic. In response to the protests, the Air Force struck a compromise in November 2003, whereby it would purchase 80 KC-767 aircraft and lease 20 more.[4][5] In December 2003, the Pentagon announced the project was to be frozen when an investigation of allegations of corruption led to the jailing of one of its former procurement executives who applied to work for Boeing.[6] The Air Force's KC-767A contract was officially canceled by the DoD in January 2006.[7]

An Italian Air Force KC-767 on the apron at McConnell AFB/Boeing Factory in Wichita, Kansas, in 2010

In 2006, the USAF released a request for proposal (RFP) for a new tanker program, KC-X, to be selected by 2007. Boeing had also announced it may enter an even higher capability tanker based on the Boeing 777, named the KC-777 Strategic Tanker. Airbus partnered with Northrop Grumman to offer the Airbus A330 MRTT, the tanker version of the A330, which was being marketed to the USAF under the company name, KC-30.[8]

In late January 2007 the USAF issued the KC-X Aerial Refueling Aircraft Request for Proposal. The RFP called for 179 (4 system development and demonstration and 175 production) tankers, in a contract worth an estimated US$40 billion.[9] However, Northrop and EADS expressed their displeasure at how the RFP was structured and threatened to withdraw, leaving only Boeing to offer an aircraft.[10]

On 12 February 2007, Boeing announced it was offering the KC-767 Advanced Tanker for the KC-X Tanker competition.[11] Boeing stated that for KC-X's requirements, the KC-767 was a better fit than the KC-777.[12] On 11 April 2007, Boeing submitted its KC-767 tanker proposal to U.S. Air Force.[13] The KC-767 Advanced Tanker offered for this KC-X round was based on the in-development 767-200LRF (Long Range Freighter), rather than the -200ER on which Italian and Japanese KC-767 aircraft are based[14] differing by combining the -200ER fuselage, -300F wing, gear, cargo door and floor, -400ER digital flightdeck and flaps, uprated engines, and "sixth-generation" fly-by-wire fuel delivery boom.[15] The KC-767 uses manual flight control, allowing unrestricted maneuverability to avoid threats anywhere in the flight envelope.[16]

Boeing submitted the final version of its proposal on 3 January 2008.[17] On 29 February 2008, the DoD chose the Northrop Grumman/EADS KC-30, over the KC-767. The KC-30 was subsequently designated KC-45A by the Air Force.[18] Boeing submitted a protest to the United States Government Accountability Office on 11 March 2008 and began waging a public relations campaign in support of their protest.[19] On 18 June, following a series of admissions by the Air Force on the flaws in the bidding process, the GAO upheld Boeing's protest and recommended the contract be rebid.[19] On 9 July 2008, Defense Secretary Robert Gates announced that the Air Force would reopen bidding on the tanker contract.[20] Secretary Gates put the contract for the KC-45 into an "expedited recompetition" with Defense Undersecretary John Young in charge of the selection process instead of the Air Force.[21] A draft of the revised RFP was provided to the contractors on 6 August 2008 for comments. By mid-August the revised RFP was to be finalized.[22] However, on 10 September 2008, the U.S. Defense Department canceled the KC-X solicitation.[23]

On 24 September 2009, the USAF began the first steps in the new round of bids, with a clearer set of criteria, including reducing the number of requirements from 800 to 373 in an attempt to simplify the process and allow a more objective decision to be made.[24] On 4 March 2010, Boeing announced it would bid the KC-767 tanker for the new KC-X round.[25] EADS announced in April 2010 it would submit a tanker bid without Northrop Grumman as a U.S. partner.[26][27] Boeing submitted its KC-767 "NewGen Tanker" bid on 9 July 2010.[28][29] The company submitted a revised bid on 10 February 2011.[30]

In addition to the KC-X, observers speculate that a modified KC-46 will be used as the basis of the KC-Y tanker program, the second step of the Air Force's three-step tanker renewal plan, as altering the KC-46 process and replacing it with something entirely new is likely too big a risk.[31]

On 24 February 2011, the Air Force announced the selection of Boeing's KC-767 tanker bid. The aircraft was designated KC-46A.[32][33] Boeing was also awarded a development contract for the tanker. The contract calls for Boeing to complete and deliver 18 initial operational KC-46 tankers by 2017. The Air Force is seeking to receive a total of 179 new tankers.[34] Boeing's "NewGen Tanker" is based on the 767-200 with an improved version of the KC-10 refueling boom, and cockpit displays from the 787.[35][36]

In late June 2011, it was reported that development costs were projected to overrun by about $300 million. Boeing would be responsible for this amount, which exceeds the contract cost cap of $4.9 billion.[37][38] In July 2011, revised cost projections indicated a reduced cost overrun.[39] In March 2015, the program cost for development and procurement of 179 tankers was projected to total US$43.16 billion.[40]

In 2013, the USAF added additional crews and flight hours for the aircraft to their future plans in response to a review that showed that the best of current plans did not take full advantage of the KC-46's cargo and aeromedical evacuation advantages over the KC-135.[41]

On 21 August 2013, Boeing and the Air Force completed a critical design review (CDR) for the KC-46. With the CDR complete, the KC-46 design was set and production and testing could proceed. Assembly of the wing for the first aircraft began on 26 June 2013. Flight testing of the Boeing 767-2C airframe, which would be reconfigured into the KC-46, was scheduled to begin in mid-2014. The first fully equipped KC-46 tanker was projected to fly in early 2015. The contract calls for Boeing to build four test aircraft and deliver 18 combat-ready tankers by August 2017. The Air Force intended to buy 179 KC-46s, with all delivered by 2028.[42][43]

On 12 December 2013, Boeing joined the wings and fuselage for the first 767-2C to be adapted into a KC-46A.[44] On 23 December 2013, the first two PW4062 engines were delivered.[45] The first of four 767-2C provision freighters were to complete assembly by the end of January 2014. Once assembled, it would go through ground vibration and instrumentation testing and have body fuel tanks added. The first test flight would occur during summer 2014 and include measuring its rate of climb and descent. The Engineering Manufacturing and Design (EMD) model would be integrated with instrumentation, electronics, and technologies needed to become a military-standard KC-46A by January 2015. Seven low-rate production KC-46s are to be delivered in 2015, 12 in 2016, and 15 delivered annually from 2017 to 2027. The KC-46A can carry 212,299 lb (96,297 kg) of fuel,[46] 10 percent more than the KC-135, and 65,000 lb (29,000 kg) of cargo. It has both a probe and drogue and a boom and receptacle to conduct multiple refueling missions on a single mission. Survivability is improved with infrared countermeasures and the aircraft has limited electronic warfare capabilities.[47] The airframe can be configured to carry 114 passengers and to serve as an aero-medical evacuation aircraft. The last of four test aircraft began assembly on 16 January 2014.[48]

In April 2014, the Government Accountability Office (GAO) found that the KC-46 program was projected to underrun its projected cost estimate of $51.7 billion by $300 million. The program acquisition unit cost per jet will also be $287 million, $1.8 million less than estimated. The GAO noted that delays in training air crew and maintainers could cause testing to slip 6–12 months, but also stated that the program had not missed any major milestones and that the development of about 15.8 million lines of software code was progressing as planned.[49] In May 2014, the Air Force estimated the cost of the development program, including the first four aircraft, could rise from $4.4–4.9 billion to $5.85 billion.[50]

In July 2014, Boeing recorded a $272 million pre-tax charge to cover a redesign of the tanker's wiring.[51][52] The wiring issue arose when it was found that 5-10% of the wiring bundles did not have sufficient separation distance or were not properly shielded to meet an Air Force requirement for double or triple-redundant wiring for some mission systems. In September 2014, it was confirmed that the wiring redesign would delay the first 767-2C flight from June 2014 to November 2014.[53][54]

The 767-2C's first flight took place on 28 December 2014; it flew from Paine Field and landed at Boeing Field.[55][56]

In July 2015, Boeing announced that it had taken a further $835 million pretax charge to pay for redesigns and retrofits required to address a faulty integrated fuel system. A Boeing spokesperson stated that “in preparing for and performing fuel system qualification testing, we identified a number of fuel system parts and components that did not meet specifications and needed to be redesigned. We're adding the engineers and ancillary staff resources needed to support the engineering redesign, manufacturing retrofit and qualification and certification of the fuel system changes, and the conclusion of functional and flight testing."[57] Boeing may have to wait an extra eight months for $3 billion in contracts on the KC-46 because of delays caused by the wiring and fuel system parts flaws, according to the USAF. Low-rate production contracts to build the first 19 of the tankers may be delayed from August to as late as April 2016 in the latest schedule revision agreed on by the Air Force and Boeing. The planned first flight of a fully equipped KC-46 is being delayed to as late as September 2015. Air Force Spokesman, Charles Gulick, noted that the primary goal, "delivery of 18 tankers by August 2017" can be met.[58] The Bank of America/Merrill Lynch noted in July 2015 “We fail to understand how Boeing could take a $1.26 billion pre-tax charge (since it won the contract over Airbus) on the Boeing KC-46A program since the program is based on the 767 airframe that has been in production for over 30 years.”[59]

On 24 January 2016, the KC-46 successfully refueled an aircraft for the first time during a 5-hour 36 minute sortie just over the shared coast of Washington state and Oregon. This refueling was with an F-16. Next the KC-46 was to test refueling a number of other military aircraft, including a C-17, F/A-18, A-10, and AV-8B.[60] On 10 February, a test KC-46 refueled an F/A-18 in the first via its probe and drogue system.[61]

On 22 March 2016, it was reported that the DoD's Defense Contract Management Agency had "low confidence in Boeing's ability" to meet the August 2017 deadline. The agency predicts that the first 18 refueling aircraft would be delivered about seven months late, by March 2018. This is based on "past performance, current risks", such as delays in production, its assessment of new joint Air Force-Boeing schedule review, and the uncertainties with flight testing. The agency may revise its schedule estimate by June 2016. The Pentagon's test office is to begin the tanker's combat testing in late April 2017.[62]

Boeing KC-46A refuels an A-10 Thunderbolt II

In March 2015, a refueling test with a C-17 transport aircraft was stopped because of a higher-than-expected boom axial load while delivering fuel. A Boeing spokesman stated "We don't yet know the schedule impact to the planned May (2016) Milestone C decision, but the problem is well understood and we don't expect an extended delay." The problem was caused by the turbulent "bow wave effect" generated by two large aircraft flying in line.[63][64][65]

The April 2016 Report from the U.S. Government Accountability Office (GAO) described Boeing's test schedule for the KC-46 program as “optimistic” and projects Boeing will need an additional four months beyond the August 2017 target to deliver 18 full-up tankers due to testing and parts qualification issues. The report notes that operational testing will not now begin until May 2017 and will not be completed until two months after the first tranche of 18 aircraft are delivered, risking late discoveries of problems. The GAO also noted that Boeing has not obtained Federal Aviation Administration's approval for two key aerial refueling systems - the centerline drogue system and the wing aerial refueling pods, which were built without following FAA processes. Boeing now projects these components will be ready for the FAA to certify by July 2017 — over three years late.[66] The 18 aircraft were meant to include the four developmental aircraft, brought up to an operational standard, plus the first 14 low-rate production (LRP) examples. Instead, 16 of the 18 will be production line examples; because the aircraft will be delivered before operational testing is complete, Boeing will be responsible for any late design fixes.[67]

In April 2016, Boeing announced that it would closely integrate its 767 and 747 programs. Bruce Dickinson, Vice President and General Manager for these programs said "The 767 production line is quite full, so the pressure we see for that is growing. We are getting to the point where we will see by next year the line alternating as tanker-freighter-tanker-freighter." More aircraft will be assembled on the 767 line in 2016 than delivered. About 22 KC-46 aircraft are to be built and an estimated 13 delivered during the year.[68]

On 25 April 2016, the fourth test aircraft, 767-2C EMD-3 first flew. It performed operational engine checks, flight controls, and environmental systems checks, while flying to a maximum altitude of 39,000 ft. EMD-3 will conduct environmental control system testing, including hot day/cold day testing and smoke penetration testing.[69]

On 27 April 2016, Boeing took another pre-tax charge for cost overruns on the program of $243 million, bringing the total amount Boeing has paid for tanker-related cost overruns to $1.5 billion to date. "This third charge allows Boeing to maintain schedule with concurrency between late-stage development testing and the transition to initial production." The charge will be split between Boeing Commercial ($162 million) and Boeing Military ($81 million). Boeing president and chief executive Dennis Muilenburg stated that 80% of the test points required for a positive Milestone C decision had been completed.[70]

On 3 May 2016, US Air Force spokesman Daryl Mayer confirmed that Milestone C review was now expected to occur in June, "subject to completion of flight test verification" of a fix to refueling system glitches. "The problem is well understood."[71] A spokesman for the US Air Force's tanker directorate at Wright-Patterson AFB, Ohio also confirmed that flight testing being conducted will help determine whether the fault can be resolved with a software tweak, or a potentially more difficult hardware change. Boeing has been working hardware and software solutions in parallel. “Boeing is flight testing a software fix to the boom axial loads issue now; once that fix is fully verified in flight, the C-17 and A-10 refueling demonstrations will begin, which we anticipate to occur in late May."[72]

On 26 May 2016, it was reported that the program would face a further delay of at least six months, due to "technical and supply chain problems". This might require the program to be re-structured or for funding to be cut, either by Congress or the Pentagon. At this time, Boeing has only completed 20% of the development flight tests. A report from The Senate Appropriations Committee on the fiscal 2017 defense spending bill, issued on the same day, expressed concerns about the aircraft's future.[73] The initial 18 aircraft are to be equipped with the refueling boom and centerline drogue, but not the wing-mounted wing-aerial refueling pods (WARP). The WARP systems, which are required to complete full contractual Required Assets Available (RAA), will be delivered separately in October 2018. Boeing stated "The underlying production system remains on track, and Boeing will have more than 18 aircraft through the factory line and in various stages of final change incorporation and certification by August 2017."[74]

A KC-46A connects with an F-35A Lightning II in the skies over California, Jan. 2019

On 2 June 2016, USAF spokesman Maj. Rob Leese confirmed that, while the Air Force's KC-46 contract with Boeing does not contain any predefined penalties for schedule delays, not delivering the 18 certified tankers by August 2017 is a contract schedule breach. "The Air Force will secure consideration from Boeing as part of the schedule re-baseline that is about to commence following the RRA delay announcement."[75][76] On 12 July 2016, Frank Kendall, US Defense Acquisitions Chief, confirmed that the tanker program office was analyzing the likely costs for the service arising from the delay. "The government is losing some of the value that we have contracted for, so we are entitled to some consideration for that. The program office has several ideas for how we might do that, and they're talking to Boeing." The USAF would incur additional costs were it necessary to operate the KC-135 fleet for longer than planned.[77]

A KC-46A connects with a B-2 Spirit over California, Apr. 2019

On 8 June 2016, Boeing's defense unit CEO, Leanne Caret, reported that a modified boom would be flown the following month. A hydraulic relief valve system would be installed so that if loads build up on the boom, the valves open to relieve the pressure. The system is similar to equipment used on the booms of the KC-10 and KC-767 tankers.[78] On 10 July 2016, Caret reported 'positive' early results after flight tests with the revised boom commenced the previous week.[77]

On 5 July 2016, Air Force spokesman Daryl Mayer stated that while KC-46 developmental testing was moving “slower than planned,” the program was on track to hit Milestone C the following month. He also stated that Boeing would add a fifth engineering and manufacturing development (EMD) aircraft to the fleet to accelerate the flight test program. EMD-1 and EMD-3 are primarily conducting flight tests required to secure FAA airworthiness certificates, while EMD-2 and EMD-4 are primarily focused on Air Force aerial refueling and other mission system testing.[79]

A KC-46A connects with a C-5M Galaxy over California, Apr. 2019

An F-16 was successfully refueled on 8 July, and a C-17 on 12 July 2016. Once the hardware fix is verified, a KC-46 with the updated boom will complete regression testing on the F-16, followed by refueling demonstrations with the C-17 and A-10 to meet the final test for Milestone C approval. USAF chief of staff, General David Goldfein, commented "While it took some time, this week's results confirm my confidence the Boeing team will get this figured out. It's reassuring to see the program take this important step toward the production decision in August."[80][81] On 15 July 2016 the KC-46 successfully refueled an A-10; during a four-hour flight, the KC-46 offloaded 1,500 pounds of fuel at 15,000 feet. "This completed the required air refueling demonstrations needed for the upcoming production milestone decision," said Boeing spokesman Chick Ramey. To date, more than 900 flight test hours have been completed with the five test aircraft.[82]

On 21 July 2016, Boeing stated it would take a further $393 million charge on the KC-46 tanker program, bringing the total value of penalties to almost $1.9 billion. The charge reflects higher costs associated with the program's current schedule and technical challenges, which include "implementation of the hardware solution to resolve the refueling boom axial load issue identified during flight testing, delays in the certification process and concurrency between late-stage development testing and initial production."[83]

On 12 August 2016, the KC-46 program received Milestone C approval from the undersecretary of defense for acquisition, technology, and logistics, indicating that it is ready to enter production. Boeing was expected to receive initial contracts for two lots of 19 aircraft total in the next 30 days.[84]

In September 2016, Air Mobility Command announced they were abandoning plans to have the follow-on KC-Y acquisition program to replace the remainder of the KC-135 fleet, instead turning it into a "bridge" for further KC-46 orders with some upgrades.[85]

In January 2018, Air Mobility Command stated that tests for final FAA certification of the KC-46 is roughly 94 percent complete.[86]

Boeing announced its FAA certification on 4 September 2018, with military certification outstanding. Aircraft refueled during testing include the F-16, F/A-18, AV-8B, C-17, A-10, KC-10, KC-135 and the KC-46 itself.[87]

On 22 January 2019, a KC-46 from the 418th Flight Test Squadron at Edwards AFB made connection with an F-35A. It is the first time the KC-46 connected with a fifth-generation jet fighter.[88] Completion of refueling certification of the F-35 by the KC-46 was announced by the 412th Test Wing on June 5, 2019.[89]

On 22 March 2019, the USAF announced it was reviewing KC-46 training after the Boeing 737 MAX groundings, as the KC-46 uses a similar Maneuvering Characteristics Augmentation System (MCAS) to that implicated in two 737 MAX crashes. However, the KC-46 is based on the Boeing 767-2C and its system takes input from dual redundant angle of attack sensors; it will disengage with stick input by the pilot. The Air Force stated that "The KC-46 has protections that ensure pilot manual inputs have override priority" and that it "does not fly the models of aircraft involved in the recent accidents" and that it is "reviewing our procedures and training as part of our normal and ongoing review process."[90]

On 30 March 2020, the Air Force announced that chronic leaks in the aircraft's fuel system had been upgraded to a Category I deficiency. The Air Force identified the issue in June 2019 but had not originally believed it to be serious. At the time of the announcement there was no known root cause for the leaks. Crews became aware of the issue when they discovered fuel between the primary and secondary fuel protection barriers.[91]

In January 2021, the losses for Boeing due to the KC-46A program were estimated at 5 billion dollars.[92] During the same month, the commander of Air Mobility Command General Jacqueline Van Ovost stated that her command was "making lemonade out of lemons" with the KC-46 by using it for a small range of tasks until deficiencies with the aircraft's refuelling system are rectified. At the time, it was expected that the KC-46 would not be combat ready until at least late 2023.[93]

In January 2018, the Indian Air Force re-launched its air-to-air refueling procurement program, and sent out a request for information for six refueling aircraft to Airbus, Boeing, and Ilyushin, to which Boeing could respond with an offer for the KC-46 Pegasus.[114] Airbus and Boeing responded to the request for information, while Ilyushin was disqualified as the official requirement is for an aircraft with two turbofan engines.[115]

In January 2018, Indonesian Air Force officials were reported as saying they were studying both the Airbus A330 MRTT and Boeing KC-46 Pegasus aerial refueling aircraft for a future modernization program, expected to take place after the current Airbus A400M Atlas program completes. The Indonesian Air Force is said to compare the aircraft on compatibility with the force's current aircraft, life-cycle costs, interoperability with current and future assets, and potential funding and technology transfer options with state-owned aircraft manufacturer Indonesian Aerospace.[116]

The Japan Air Self-Defense Force (JASDF) operates four of the earlier Boeing KC-767 tankers that were delivered from 2008 to 2010.[117] On 23 October 2015, Japan selected the KC-46 as its new tanker, with a contract for three tankers expected in 2016.[118] The decision allows for common operations and training with the USAF, and Japan was reportedly attracted to its capability to refuel MV-22 Osprey tiltrotors the JASDF is to receive. Airbus declined to bid its A330 MRTT, because they viewed Japan's request for proposals as intended for the KC-46. The three tankers are to be fielded around 2020 at a cost of more than ¥20.8 billion, about US$173 million per aircraft.[119] As of September 2019, the JASDF is reportedly looking to acquire a total of six KC-46 aircraft.[120] Work on the first KC-46 to be delivered to the JASDF began on 17 September 2019.[121] An order for a third and fourth KC-46 tanker was placed with Boeing on 30 October 2020.[122]

In June 2014, Boeing submitted the KC-46 for the Republic of Korea Air Force's requirement for four aerial tankers. The KC-46 competed with the Airbus A330 MRTT;[123] South Korea selected the Airbus A330 MRTT in June 2015.[124]

On 2 February 2017, Boeing stated it would bid the KC-46A for the Royal Canadian Air Force's Strategic Tanker Transport Capability competition, which is to replace Canada's fleet of CC-150 Polaris tankers. The contract is valued at C$1.5+ billion.[125]

On 3 March 2020, The State Department approved the Foreign Military Sale to Israel of 8 KC-46s and related equipment for a cost of $2.4 billion.[126]

Boeing pitched the KC-46 to the Polish Air Force for its tanker requirement.[127] In December 2014, Airbus was awarded a contract for four A330 MRTTs from a consortium of Poland, the Netherlands, and Norway.[128][129]

In May 2019, according to manufacturer Boeing, the United Arab Emirates made a formal request to procure three KC-46A aircraft.[130][131]