|A Boeing KC-46A with refueling boom lowered|
|Role||Aerial refueling and transport aircraft|
|Manufacturer||Boeing Defense, Space & Security|
|First flight||25 September 2015|
|Status||In service (limited use)|
|Primary user||United States Air Force|
|Developed from||Boeing KC-767|
The Boeing KC-46 Pegasus is an American military aerial refueling and strategic military transport aircraft developed by Boeing from its 767 jet airliner. In February 2011, the tanker was selected by the United States Air Force (USAF) as the winner in the KC-X tanker competition to replace older Boeing KC-135 Stratotankers. The first aircraft was delivered to the Air Force in January 2019. The Air Force intends to procure 179 Pegasus aircraft by 2027.
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. The USAF decided to lease 100 KC-767 tankers from Boeing.
US Senator John McCain and others criticized the draft leasing agreement as being wasteful and problematic. In response to protests, the USAF struck a compromise in November 2003, whereby it would purchase 80 KC-767s and lease 20 more. In December 2003, the Pentagon announced a freeze on the program over an investigation into alleged corruption that led to the jailing of one of its former procurement executives who applied to work for Boeing. The KC-767A contract was officially canceled by the DoD in January 2006.
In 2006, the USAF released a request for proposal (RFP) for a new tanker program, KC-X, to be selected by 2007. Boeing 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 marketed to the USAF under the designation KC-30. In January 2007, the USAF issued the KC-X Aerial Refueling Aircraft RFP, calling for 179 tankers (four system development and demonstration and 175 production), in a contract worth an estimated US$40 billion. However, Northrop and EADS expressed dissatisfaction at how the RFP was structured and threatened to withdraw, leaving only Boeing in the running.
On 12 February 2007, Boeing announced it was offering the KC-767 Advanced Tanker for the KC-X Tanker competition. Boeing stated that for KC-X's requirements, the KC-767 was a better fit than the KC-777. On 11 April 2007, Boeing submitted its KC-767 tanker proposal to USAF. 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 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. The KC-767 uses manual flight control, allowing unrestricted maneuverability to avoid threats anywhere in the flight envelope.
Boeing submitted the final version of its proposal on 3 January 2008. 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 USAF. 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. On 18 June, following a series of admissions by the USAF on flaws in the bidding process, the GAO upheld Boeing's protest and recommended the contract be rebid. On 9 July 2008, Defense Secretary Robert Gates announced that the USAF would reopen bidding on the tanker contract. 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. 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. However, on 10 September 2008, the U.S. Defense Department canceled the KC-X solicitation.
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. On 4 March 2010, Boeing announced it would bid the KC-767 tanker for the new KC-X round. EADS announced in April 2010 it would submit a tanker bid without Northrop Grumman as a U.S. partner. Boeing submitted its KC-767 "NewGen Tanker" bid on 9 July 2010. The company submitted a revised bid on 10 February 2011.
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.
On 24 February 2011, the USAF announced the selection of Boeing's KC-767 tanker bid. The aircraft was designated KC-46A. 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. 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.
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. In July 2011, revised cost projections indicated a reduced cost overrun. In March 2015, the program cost for development and procurement of 179 tankers was projected to total US$43.16 billion.
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.
On 21 August 2013, Boeing and the USAF completed a critical design review (CDR) for the KC-46. With the CDR complete, the design was set and production and testing could proceed. Wing assembly for the first aircraft began on 26 June 2013. Flight testing of the 767-2C airframe, which would be reconfigured into the KC-46, was scheduled to begin in mid-2014. The first fully-equipped KC-46 was projected to fly in early 2015. The contract called for Boeing to build four test aircraft and deliver 18 combat-ready tankers by August 2017. The USAF intended to buy 179 KC-46s, with all delivered by 2028.
On 12 December 2013, Boeing joined the wings and fuselage for the first 767-2C to be adapted into a KC-46A. On 23 December 2013, the first two PW4062 engines were delivered. 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 was to be integrated with the needed systems and technologies to become a military-standard KC-46A by January 2015. Seven low-rate production KC-46s were to be delivered in 2015, 12 in 2016, and 15 delivered annually from 2017 to 2027. The last of four test aircraft began assembly on 16 January 2014.
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. In May 2014, the USAF estimated the development program's cost, including the first four aircraft, could rise from $4.4–4.9 billion to $5.85 billion.
In July 2014, Boeing recorded a $272 million pre-tax charge to cover the tanker's wiring redesign. 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 a USAF 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.
The 767-2C's first flight took place on 28 December 2014; it flew from Paine Field and landed at Boeing Field. In March 2015, a refueling test with a C-17 transport was stopped because of a higher-than-expected boom axial load while delivering fuel; the problem was caused by the turbulent "bow wave effect" generated by two large aircraft flying in line. On 24 January 2016, the KC-46 successfully refueled an F-16 for the first time during a 5 hour 36 minute sortie. Test refueling of several other military aircraft followed, including a C-17, F/A-18, A-10, and AV-8B. On 10 February, a KC-46 refueled an F/A-18, using its probe-and-drogue system for the first time.
In July 2015, Boeing announced a further $835 million pretax charge for the redesign and retrofit of a faulty integrated fuel system. Wiring and fuel system flaws could delay contracts worth $3 billion for up to eight months; following schedule revisions agreed by the USAF and Boeing, the first flight of a fully equipped KC-46 was delayed to as late as September 2015. 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.”
On 22 March 2016, it was reported that the DoD's Defense Contract Management Agency had low confidence that Boeing could meet the August 2017 deadline, predicting the delivery of the first 18 tankers to run about seven months late based on past performance and current risks, such as production delays, a new joint USAF-Boeing schedule review, and flight testing uncertainties. The Pentagon's test office was to start combat testing in April 2017.
An April 2016 GAO report described the test schedule as “optimistic” and projected an additional four months beyond the August 2017 target to deliver 18 full-up KC-46s due to testing and parts qualification issues. The report noted that operational testing will not begin until May 2017 and will not be completed until two months after delivery of the first 18 aircraft, 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 projected these systems would be ready for FAA certification by July 2017 — over three years late. The 18 KC-46s were to include the four EMD aircraft, raised to operational standards, plus the first 14 low-rate production (LRP) examples. Instead, 16 of the 18 will off the production line; Boeing is also liable for all late design fixes on tankers delivered before operational testing ends.
On 25 April 2016, the fourth test aircraft, 767-2C EMD-3, first flew. EMD-3 will focus on environmental control systems, including hot/cold testing and smoke penetration testing. Two days later, Boeing took another pre-tax charge of $243 million for cost overruns, bringing the total amount Boeing had paid for tanker-related cost overruns to $1.5 billion. Boeing president and chief executive Dennis Muilenburg stated that 80% of the test points required for a positive Milestone C decision had been completed.
On 3 May 2016, USAF spokesman Daryl Mayer confirmed that Milestone C review was expected to occur in June, if flight test verification of a fix to refueling issues was promptly completed. Flight testing was conducted to help determine whether the fault could be resolved by a software change, or a potentially more difficult hardware change. Boeing worked on both hardware and software solutions in parallel. On 26 May 2016, a further delay of at least six months due to technical and supply chain issues was reported, potentially requiring the program's re-structuring and funding cuts. At the time, Boeing had only completed 20% of the development flight tests. A report by the Senate Appropriations Committee on the fiscal 2017 defense spending bill noted concerns over the KC-46. 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). These pods, which are needed for full contractual Required Assets Available (RAA), will be delivered separately in October 2018.
On 2 June 2016, USAF spokesman Maj. Rob Leese confirmed that, while the contract with Boeing lacked predefined penalties for delays, not delivering the 18 certified tankers by August 2017 is a contract schedule breach, and that the USAF would receive considerations from Boeing in the schedule re-baseline after the RRA delay. On 12 July 2016, Frank Kendall, US Defense Acquisitions Chief, confirmed that the tanker program office was studying the delay's likely costs to the USAF, and that the service was entitled to consideration for losses. The USAF would incur additional costs if the KC-135 was operated for longer than planned.
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, similar to equipment used on the booms of the KC-10 and KC-767 tankers, would be installed so that if loads build up on the boom, the valves open to relieve the pressure. On 10 July 2016, Caret reported positive early results after flight tests with the revised boom commenced the previous week. On 21 July 2016, Boeing took a further $393 million charge on the KC-46 program, bringing the total value of penalties to almost $1.9 billion. The charge reflected higher costs associated with the schedule and technical challenges, which include resolving the refueling boom axial load issue, delays in the certification process and concurrency between testing and initial production.
On 5 July 2016, USAF spokesman Daryl Mayer stated that while testing was slower than planned, Milestone C approval was expected in the following month, and that Boeing would add a fifth EMD aircraft to accelerate flight testing. EMD-1 and EMD-3 primarily conducted flight tests towards FAA airworthiness certificates, while EMD-2 and EMD-4 focused on USAF aerial refueling and mission system testing. 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 underwent regression testing on the F-16, followed by refueling demonstrations with the C-17 and A-10 for the final test for Milestone C approval. On 15 July 2016, the KC-46 successfully refueled an A-10, offloading 1,500 pounds of fuel at 15,000 feet. At the time, more than 900 flight test hours have been completed by the five EMD aircraft.
On 12 August 2016, the program received Milestone C approval from the undersecretary of defense for acquisition, technology, and logistics, indicating production readiness; the issuing of contracts for two lots covering 19 aircraft was expected within 30 days. In September 2016, Air Mobility Command stated that the follow-on KC-Y acquisition program to replace the remaining KC-135s had been abandoned in favour of further KC-46s with upgrades.
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. In January 2018, Air Mobility Command stated that tests for final FAA certification of the KC-46 is roughly 94 percent complete. On 22 January 2019, a KC-46 from the 418th Flight Test Squadron at Edwards AFB made connection with an F-35A, the occasion being the first time that the KC-46 connected with a fifth-generation jet fighter. Completion of refueling certification of the F-35 by the KC-46 was announced by the 412th Test Wing on 5 June 2019.
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.
On 30 March 2020, the USAF announced that chronic leaks in the fuel system had been upgraded to a Category I deficiency. The USAF identified the issue in June 2019, but had not originally believed it to be serious. Crews became aware of the issue when they discovered fuel between the primary and secondary fuel protection barriers; there was no known root cause at the time of the announcement. By January 2021, Boeing's losses on the program were estimated at $5 billion. At the time, it was expected that the KC-46 would not be combat ready until at least late 2023.
The Pegasus is a variant of the Boeing 767 and is a widebody, low-wing cantilever monoplane with a conventional tail unit featuring a single fin and rudder. It has a retractable tricycle landing gear and a hydraulic flight control system. The Pegasus is powered by two Pratt & Whitney PW4062 engines, one mounted under each wing. The KC-46 has been described as combining "the 767-200ER's fuselage, with the 767-300F's wing, gear, cargo door and floor, with the 767-400ER digital flightdeck and flaps".
The flightdeck has room for a crew of four with a forward crew compartment with seats for 15 crew members and in the rear fuselage either palletized passenger seating for 58, or 18 pallets in cargo configuration. The rear compartment can also be used in an aero-medical configuration for 54 patients (24 on litters). The KC-46A can carry 212,299 lb (96,297 kg) of fuel, 10 percent more than the KC-135, and 65,000 lb (29,000 kg) of cargo. Survivability is improved with infrared countermeasures and the aircraft has limited electronic warfare capabilities. There is a ladder that can be pulled down near the front landing gear to provide quick ingress to the aircraft for rapid deployment situations.
At the rear of the aircraft is a fly-by-wire refueling boom supplemented by wing air refueling pods at each wingtip and a centerline drogue system under the rear fuselage.
On 23 April 2014, the USAF announced that the KC-46 Pegasus will be based at McConnell Air Force Base in Wichita, Kansas, with an optimistic expectation that the base would start receiving the first of 36 tankers in 2016. At the time of the announcement, the KC-135 Stratotanker was stationed at this base. McConnell AFB was chosen because it had low construction costs and it is in a location with a high demand for air refueling. In addition to McConnell AFB serving as the home base, up to 10 operating bases are to be chosen for the KC-46 fleet. Crews will be trained at Altus Air Force Base, Oklahoma, which was also chosen for its limited construction needs and for its existing experience with training programs for the C-17 Globemaster and KC-135.
On 29 October 2015, the USAF announced that Seymour Johnson Air Force Base, North Carolina, was chosen as the preferred alternative for the first Reserve-led KC-46A main operating base, with an anticipated arrival of the KC-46As at Seymour Johnson in fiscal year 2019. Tinker Air Force Base, Oklahoma; Westover Air Reserve Base, Massachusetts; and Grissom Air Reserve Base, Indiana, were named as the reasonable alternatives. The October 2015 announcement also stated that the USAF intended to initiate an Environmental Impact Analysis Process (EIAP), which the USAF would use to make its final basing decisions.
On 10 January 2019, the USAF took delivery of the first KC-46, well past the originally announced 2016 delivery date, albeit with two issues outstanding and money withheld. The two outstanding issues were inadequate boom pressure when refueling the A-10 Warthog and glare induced distortion under certain conditions in the remote vision system (RVS). The USAF has acknowledged that they failed to give Boeing adequate specifications for the A-10. At milestone C, Boeing gave the USAF a boom design that used the international standard of 1400 lbs of thrust resistance, which they accepted, but A-10 is only able to generate 650 lbs.
On 2 April 2019, it was confirmed that the USAF halted all deliveries on 23 March and until further notification, as loose material and debris were found in planes already delivered.
On 12 September 2019, it was reported that the USAF restricted the KC-46 from carrying cargo and passengers due to an issue with the floor cargo locks coming unlocked in flight. A fix to this issue was approved by the Air Force on 12 November 2019 with plans to install the new cargo locks on delivered aircraft in the upcoming weeks. As of 20 December 2019, four KC-46As have received the new cargo locks and the USAF has closed the Category 1 deficiency and cleared the retrofitted aircraft for cargo and passenger operations.
As of January 2021, Boeing had delivered 42 KC-46As to the USAF and is on contract for 94 tankers.
In early 2021, the USAF cleared the KC-46 for limited operational use, years after its planned 2017 introduction. The type can conduct U.S.-based refueling only, requiring other tankers for deployments to combat areas. At the time, the KC-46 could refuel the B-52, F-15, F-16, and F/A-18, but it was not approved to service the A-10, F-22, F-35, B-1, or B-2; it is expected to be fully combat-ready by 2023.
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. 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.
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.
The Japan Air Self-Defense Force (JASDF) operates four of the earlier Boeing KC-767 tankers that were delivered from 2008 to 2010. On 23 October 2015, Japan selected the KC-46, with a contract for three tankers expected in 2016. 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. The JASDF reportedly sought to acquire a total of six KC-46s. Work on the first JASDF KC-46 began on 17 September 2019. An order for a third and fourth KC-46 was placed on 30 October 2020.
On 8 February 2021, the JASDF conducted its first flight of a KC-46 tanker.
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. However, on 1 April 2021, Airbus Defence and Space and their submission of the A330 MRTT was deemed to be the only qualified bidder to replace the CC-150.
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; South Korea selected the Airbus A330 MRTT in June 2015.
Boeing pitched the KC-46 to the Polish Air Force for its tanker requirement. In December 2014, Airbus was awarded a contract for four A330 MRTTs from a consortium of Poland, the Netherlands, and Norway.
Aircraft of comparable role, configuration, and era
There’s also a compartment on the belly of the plane, which can be opened so crew can pull down a ladder, climb up, and quickly board the plane. "If you need to get inside faster you can climb up this ladder, step on a platform, climb up another ladder and end up in the floor of the plane,” Zubricki said.
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