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 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 a 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 (~$54.7 billion in 2022).[12] Northrop and EADS expressed dissatisfaction at how the RFP was structured and threatened to withdraw, leaving only Boeing in the running. In February 2007, Boeing announced it was offering the KC-767 Advanced Tanker for the KC-X, stating that the KC-767 was a better fit than the KC-777 for the requirements. In April 2007, Boeing submitted its KC-767 tanker proposal to USAF. The KC-767 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. Boeing submitted its final proposal in January 2008. In February 2008, the DoD chose the KC-30 over the KC-767, the USAF subsequently designated it KC-45A. Boeing submitted a protest to the United States Government Accountability Office in March 2008 and waged a public relations campaign in support of their protest. In June, after USAF admissions on bidding process flaws, the GAO upheld Boeing's protest and recommended the contract be rebid. In July 2008, Defense Secretary Robert Gates announced that the USAF would reopen bidding, and put the contract into an "expedited recompetition" with Defense Undersecretary John Young in charge of the selection process, not the USAF. A draft of the revised RFP was provided to contractors in August 2008 for comments. However, in September 2008, the DoD canceled the KC-X solicitation. In September 2009, the USAF began a 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. In March 2010, Boeing announced it would bid the KC-767 for the new KC-X round. EADS stated in April 2010 it would submit a bid without Northrop Grumman as a U.S. partner. Boeing submitted its KC-767 "NewGen Tanker" bid, based on the 767-200 with an improved version of the KC-10's refueling boom, and cockpit displays from the 787, in July 2010. Boeing submitted a revised bid in 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 USAF's three-step tanker renewal plan, as replacing it with something entirely new is likely too big a risk. 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 favor of further KC-46s with upgrades. The KC-46 Pegasus is a variant of the Boeing 767 and is a widebody, low-wing cantilever monoplane with a conventional empennage 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. It 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".[90] The KC-46 uses a similar Maneuvering Characteristics Augmentation System (MCAS) to that implicated in two 737 MAX crashes; in March 2019, the USAF began reviewing KC-46 training due to this feature. Unlike the 737, the KC-46's MCAS takes input from dual redundant angle of attack sensors and disengages with stick input by the pilot. 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). Quick ingress from the ground is available via a ladder that can be pulled down near the front landing gear. 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. It uses manual flight controls, allowing unrestricted maneuverability to avoid threats anywhere in the flight envelope. At the rear of the KC-46 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 so it can handle both types of refueling in one mission. The boom includes a hydraulic relief valve system, similar to those on the KC-10 and KC-767 tankers, to relieve axial pressure in the event of excessive loads building up on the boom. In order to address the stiff boom issue, which keeps a KC-46 from refueling lightweight, thrust-limited receivers like the A-10, Boeing is replacing the current actuator with one using a pressure-flow PQ valve in the 2023 time frame. Rather than using a single boom operator seated or prone at the tail looking out a window, the Aerial Refueling Operator Station (AROS) seats two operators at the front of the tanker. AROS includes three main displays for each operator to display images from multiple multi-spectral cameras distributed around the aircraft. The central 2D/3D display provides a rear-facing view for boom refueling operations. Boom operators can execute their mission in total darkness with both aircraft blacked out. The hybrid 2D-3D system requires stereoscopic glasses to be fully effective. The Remote Vision System (RVS) that feeds video to the AROS has been problematic, motion viewed in the RVS versus which can create a depth compression and curvature effect. Blackouts and washouts on the displays during refueling, caused by shadows or direct sunlight are a problem that will be fixed by the RVS 2.0 upgrade along with depth perception issues via the use of new cameras and a full-color high-definition screen. Experienced boom operators of older tankers still prefer the KC-46, even with its current drawbacks.
