| F-22 Raptor | |
|---|---|
| The F-22 Raptor | |
| Role | Stealth air superiority fighter |
| National origin | United States |
| Manufacturer | Lockheed Martin Aeronautics Boeing Defense, Space & Security |
| First flight | 7 September 1997[1] |
| Introduction | 15 December 2005 |
| Status | In service, out of production[2] |
| Primary user | United States Air Force |
| Produced | 1997-2011 |
| Number built | 187 operational aircraft[3] |
| Program cost | US$66.7 billion[4] |
| Unit cost | US$150 million (flyaway cost for FY2009)[5] |
| Developed from | Lockheed YF-22 |
| Developed into | Lockheed Martin X-44 MANTA Lockheed Martin FB-22 |
The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals intelligence roles.[6] Lockheed Martin Aeronautics is the prime contractor and is responsible for the majority of the airframe, weapon systems and final assembly of the F-22. Program partner Boeing Defense, Space & Security provides the wings, aft fuselage, avionics integration, and training systems.
The aircraft was variously designated F-22 and F/A-22 during the years prior to formally entering USAF service in December 2005 as the F-22A. Despite a protracted and costly development period, the United States Air Force considers the F-22 a critical component of US tactical air power, and claims that the aircraft is unmatched by any known or projected fighter,[7] while Lockheed Martin claims that the Raptor's combination of stealth, speed, agility, precision and situational awareness, combined with air-to-air and air-to-ground combat capabilities, makes it the best overall fighter in the world today.[8] Air Chief Marshal Angus Houston, former Chief of the Australian Defence Force, said in 2004 that the "F-22 will be the most outstanding fighter plane ever built."[9]
The high cost of the aircraft, a lack of clear air-to-air combat missions because of delays in the Russian and Chinese fifth-generation fighter programs, a US ban on Raptor exports, and the ongoing development of the planned cheaper and more versatile F-35 resulted in calls to end F-22 production.[N 1] In April 2009 the US Department of Defense proposed to cease placing new orders, subject to Congressional approval, for a final procurement tally of 187 operational aircraft.[11] The National Defense Authorization Act for Fiscal Year 2010 lacked funding for further F-22 production. The final F-22 rolled off the assembly line on 13 December 2011 during a ceremony at Dobbins Air Reserve Base.[2]
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In 1981, the U.S. Air Force developed a requirement for an Advanced Tactical Fighter (ATF) as a new air superiority fighter to replace the F-15 Eagle and F-16 Fighting Falcon. This was influenced by the emerging worldwide threats, including development and proliferation of Soviet Su-27 "Flanker"- and MiG-29 "Fulcrum-class fighter aircraft. It would take advantage of the new technologies in fighter design on the horizon including composite materials, lightweight alloys, advanced flight-control systems, more powerful propulsion systems and stealth technology. A request for proposals (RFP) was issued in July 1986, and two contractor teams, Lockheed/Boeing/General Dynamics and Northrop/McDonnell Douglas were selected on 31 October 1986 to undertake a 50-month demonstration phase, culminating in the flight test of two prototypes, the YF-22 and the YF-23.[12][13][14]
Each design team produced two prototypes featuring one of two engine options, one featuring thrust vectoring. The Pratt & Whitney F119 turbofan with vectored thrust permits a tighter turning radius, a valuable capability in dogfights. During the development process, the ATF's increasing weight and cost drove out some features. A dedicated infra-red search and track (IRST) system was downgraded from multi-color to single color then deleted, the side-looking radars were deleted and the ejection seat requirement was downgraded from a fresh design to the existing McDonnell Douglas ACES II.[15]
On 23 April 1991, the YF-22 was announced by Secretary of the Air Force Donald Rice as the winner of the ATF competition.[16] The YF-23 design was more stealthy and faster, but the YF-22 was more agile.[17] The aviation press speculated that the YF-22 was also more adaptable to the Navy's Navalized Advanced Tactical Fighter (NATF), but the US Navy abandoned NATF by 1992.[18] In 1991, the Air Force planned to buy 650 aircraft.[19]
The production F-22 model was unveiled on 9 April 1997 at Lockheed Georgia Co., Marietta, Georgia. It first flew on 7 September 1997. The first production F-22 was delivered to Nellis Air Force Base, Nevada, on 7 January 2003.[20] In 2006, the Raptor's development team, composed of Lockheed Martin and over 1,000 other companies, plus the United States Air Force, won the Collier Trophy, American aviation's most prestigious award.[21] In 2006, the USAF sought to acquire 381 F-22s, to be divided among seven active duty combat squadrons and three integrated Air Force Reserve Command and Air National Guard squadrons.[22]
Several design changes were made from the YF-22 for production. The swept-back angle on the wing's leading edge was decreased from 48° to 42°, while the vertical stabilizer area was decreased by 20%. To improve pilot visibility, the canopy was moved forward 7 inches (178 mm), and the engine intakes were moved rearward 14 inches (356 mm). The shape of the wing and stabilator trailing edges was refined to improve aerodynamics, strength, and stealth characteristics.[23][24] Also, the vertical stabilizer was shifted rearward.[25]
F-22 production was split up over many subcontractors across 46 states, in a strategy to increase Congressional support for the program.[26][27] However the production split, along with the use of several new technologies were likely responsible for increased costs and delays.[28] Many capabilities were deferred to post-service upgrades, reducing the initial cost but increasing total project cost.[29] Each aircraft required "1,000 subcontractors and suppliers and 95,000 workers" to build.[30] The F-22 was in production for 15 years, at a rate of roughly two per month.[31]
The United States Air Force originally planned to order 750 ATFs at a cost of $26.2 billion,[32] with production beginning in 1994; however, the 1990 Major Aircraft Review led by Defense Secretary Dick Cheney altered the plan to 648 aircraft beginning in 1996. The goal changed again in 1994, when it became 438 aircraft entering service in 2003 or 2004, but a 1997 Department of Defense report put the purchase at 339.[32] In 2003, the Air Force said that the existing congressional cost cap limited the purchase to 277. By 2006, the Pentagon said it will buy 183 aircraft, which would save $15 billion but raise the cost of each aircraft, this was implemented in the form of a multi-year procurement plan, which allowed for further orders later. The total cost of the program by 2006 was $62 billion.[22]
In April 2006, the cost of the F-22 was assessed by the Government Accountability Office to be $361 million per aircraft. By April 2006, $28 billion had been invested in F-22 development and testing; while the Unit Procurement Cost was estimated at $177.6 million in 2006, based on a production run of 181 airframes.[33][34] It was estimated by the end of production, $34 billion will have been spent on procurement, resulting in a total program cost of $62 billion, around $339 million per aircraft. The incremental cost for an additional F-22 was estimated as about $138 million.[22][35]
On 31 July 2007, Lockheed Martin received a multi-year contract for 60 F-22s worth a total of $7.3 billion.[36][37] The contract brought the number of F-22s on order to 183 and extended production through 2011.[36] To restart production would be very costly; the cost for another 75 aircraft was estimated in 2009 to be an extra $70 million per unit.[38]
No opportunity for export currently exists because the export sale of the F-22 is barred by American federal law.[39] Current customers for U.S. fighters are either acquiring earlier designs such as the F-15, General Dynamics F-16 Fighting Falcon, and Boeing F/A-18E/F Super Hornet, or are waiting to acquire the Lockheed Martin F-35 Lightning II (Joint Strike Fighter), which contains technology from the F-22 but is designed to be cheaper, more flexible, and available for export. The F-35 will not be as agile as the F-22 or fly as high or as fast, but its radar and avionics will be more advanced.[40] On 27 September 2006, Congress upheld the ban on foreign sales of the F-22;[41] and confirmed this in December 2006.[42]
The Japanese government showed interest in the F-22 for its Replacement-Fighter program.[43] However, a sale would need approval from the Pentagon, State Department and Congress. It was stated that the F-22 would decrease the number of fighters needed by the Japan Air Self-Defense Force (JASDF), reducing engineering and staffing costs. In August 2009, it was reported that the F-22 would require increases to the military budget beyond the historic 1 percent of GDP.[44] In June 2009, Japanese Defense Minister Yasukazu Hamada said that Japan still sought the F-22.[45]
Some Australian politicians and defense commentators have proposed that Australia should purchase F-22s instead of the F-35.[46][47] In 2006, the Australian Labor Party supported this proposal on the grounds that the F-22 is a proven, highly capable aircraft, while the F-35 is still under development.[48] However, Australia's Howard government ruled out purchase of the F-22, as its release for export is unlikely, and lacks sufficient ground/maritime strike capacity.[49] The following year, the Australian government ordered a review of plans to procure the F-35 and F/A-18E/F Super Hornet, including an evaluation of the F-22's suitability. The then Defence Minister Joel Fitzgibbon stated: "I intend to pursue American politicians for access to the Raptor".[50] In February 2008, U.S. Defense Secretary Robert Gates said he had no objection to F-22 sales to Australia.[51]
"The IAF would be happy to equip itself with 24 F-22s, but the problem at this time is the US refusal to sell the aircraft, and its $200 million price tag."
Thomas Crimmins of the Washington Institute for Near East Policy speculated in 2009 that the F-22 could be a strong diplomatic tool for Israel, strengthening the capability to strike Iranian nuclear facilities.[53] Crimmins also stated the F-22 may be the only aircraft able to evade Russian S-300 air defense systems, which Russia may sell to Iran.[54] However, Lockheed Martin has stated that the F-35 can handle the S-300, additionally Russia has stated they support and voted for United Nations sanctions on Iran preventing sales of the S-300.[55][56]
The 2010 defense authorization bill included provisions which required the DoD to prepare a report on the costs and feasibility for an F-22 export variant and another report on the impact of F-22 export sales on the U.S. aerospace industry.[57][58]
In 2006, David M. Walker, Comptroller General of the United States at the time, found that "the DOD has not demonstrated the need or value for making further investments in the F-22A program."[59] During the two-month grounding of nearly 700 older F-15s in 2007, some US Senators demanded Deputy Secretary of Defense Gordon England release three government reports supporting additional F-22s beyond the planned 183 jets.[60] In December 2007, the USAF requested continued production beyond the planned 183 F-22s.[61]
In January 2008, the Pentagon announced that it would ask Congress to fund additional F-22s to replace other aircraft lost in combat, and proposed that $497 million that would have been used to shut down the F-22 line be instead used to buy four extra F-22s, leaving the production line open beyond 2011 and allowing the next administration an option to buy more F-22s.[62] Funds earmarked for line shutdown were redirected to repairs upon the F-15 fleet; delaying the end of F-22 production.[63]
On 24 September 2008, Congress passed a defense spending bill funding continued production of the F-22.[64] On 12 November 2008, the Pentagon released $50 million of the $140 million approved by Congress to buy parts for an additional four aircraft, thus leaving the Raptor program in the hands of the incoming Obama Administration.[65] On 6 April 2009, Secretary of Defense Gates called for the phasing out of F-22 production in fiscal year 2011, leaving the USAF with a production run of 187 fighters, minus loses.[11] F-35 acquisition would be accelerated.[66][67] On 17 June 2009 the House Armed Services Committee inserted $368.8 million in the budget towards a further 12 F-22s in FY 2011.[68]
On 9 July 2009, General James Cartwright, Vice Chairman of the Joint Chiefs of Staff, explained to the U.S. Senate Committee on Armed Services his reasons for supporting termination of F-22 production. He stated that fifth-generation fighters need to be proliferated to all three services by shifting resources to the multirole F-35. He noted that commanders had concerns regarding electronic warfare (EW) capabilities, and that keeping the F/A-18 production line "hot" offered a fallback option to the F-35 in the EA-18G Growler.[69]
"The Pentagon cannot continue with business as usual when it comes to the F-22 or any other program in excess of our needs."
On 21 July 2009, President Obama threatened to veto F-22 funding.[72][73] On 21 July 2009, the Senate voted in favor of ending F-22 production. Secretary Gates said that the decision to end production was taken in light of the F-35's capabilities.[74] On 29 July 2009, the Air National Guard's director asked for "60 to 70" F-22s for air sovereignty missions, noting that these could lack capabilities such as ground attack.[75] On 30 July 2009, the House agreed to remove funds for an additional 12 aircraft and abide by the 187 cap.[76] In mid-2010, Gates reduced the F-22 requirement from 243 to 187 aircraft, by lowering the preparations for two major regional conflicts to one.[77] President Obama signed the National Defense Authorization Act for Fiscal Year 2010 in October 2009, without F-22 funding.[78][79]
RAND estimated the cost of restarting production to build an additional 75 Raptors to be $17 billion or $227 million per aircraft.[80] However Lockheed Martin has said that restarting the production line would only cost $200 million.[81] The RAND paper was produced as part of an USAF study to determine the costs of retaining F-22 tooling for a future Service Life Extension Program (SLEP).[82] The tooling for F-22 production will be documented in illustrated electronic manuals stored at the Sierra Army Depot.[83]
Russian and Chinese fighter developments have fueled concern; General John Corley, head of Air Combat Command, wrote in a 2009 letter to a senator, "In my opinion, a fleet of 187 F-22s puts execution of our current national military strategy at high risk in the near- to mid-term". But Gates replied "Nonsense".[84] On 8 January 2011, Gates clarified that Chinese fifth-generation fighter developments had been accounted when the number of F-22s was set, and that the United States would have a considerable advantage in stealth aircraft in 2025, even with F-35 delays.[85][86] On 11 January 2011, China's J-20 stealth aircraft made its first flight,[87] leading to speculation on the reactivation of F-22 production;[88][89][90] An August 2008 RAND study concluded the F-22 would only play a minor role in a conflict with China over Taiwan as nearby bases would be rapidly shutdown by Medium-range ballistic missiles (MRBMs); and distant bases would rely upon vulnerable aerial refueling tankers.[91][92]
In December 2011, the 195th and final F-22 was completed (out of 8 test and 187 combat aircraft produced).[93]
On 5 January 2001, Raptor 4005 flew with the Block 3.0 software, which was the first combat-capable avionics version.[94] In June 2009, Increment 3.1 was tested at Edwards Air Force Base. This provided a basic ground-attack capability through Synthetic Aperture Radar mapping, Electronic attack and the GBU-39 Small Diameter Bomb. The Increment 3.1 Modification Team with the 412th Test Wing received the Chief of Staff Team Excellence Award for upgrading 149 Raptors.[95][96] The fleet upgrade should start at the end of 2011.[97]
Increment 3.2 was to add an improved SDB capability, an automatic ground collision avoidance system for low level operations and enable use of the AIM-9X Sidewinder and AIM-120D AMRAAM missiles. However, a helmet mounted cueing system has been deferred by technical issues.[98][99] Increment 3.2 was expected to be fielded in FY15,[100] possibly including the Multifunction Advanced Data Link (MADL).[101][102] In July 2009 the USAF announced the modification of three business jets with the interim Battlefield Airborne Communications Node (BACN) to allow communication between F-22s and other platforms until MADL is installed.[103] In March 2010, the USAF accelerated software portions of the Increment 3.2 upgrades to be completed in FY 2013, other upgrades will be completed later.[104] Upgrading the first 183 aircraft to the 3.2 upgrade is estimated to cost $8 billion.[105] In May 2009, Gen. Norton A. Schwartz and Air Force Secretary Michael B. Donley gave testimony to Congress that this would be paid for through the early retirement of legacy fighters.[106] A total of 249 fourth-generation fighters were retired during Fiscal Year 2010.[107] On 16 September 2009, Gates said "Our commitment to this aircraft is underscored by the 6 and-a half billion dollars... to upgrade the existing F-22 fleet to be fully mission-capable."[108]
The USAF opened the Raptor enhancement, development and integration (FREDI) contract to other bidders in January 2011 with a total budget of $16 billion.[109] On 18 November 2011, the upgrade contract with Lockheed Martin was increased by $1.4 billion to a maximum value of $7.4 billion. This increment opens the way for further upgrades in 2012.[110][111][112]
Lockheed Martin has proposed upgrades to add capabilities from the newer F-35.[113] Elements such as MADL are delayed until the F-35 program is completed to reduce risk.[114] One upgrade from the F-35 is new high-durability stealth coatings to lower maintenance.[115] The Ada software language was blamed for slow progress and increased costs on the program, leading to a reorganization in 2011.[116] Increment 3.2A in 2014 focuses on electronic warfare, communications and identification. Increment 3.2B in 2017 will support the AIM-9X and AIM-120D missiles. Increment 3.2C in 2019 may migrate some avionics to an open platform, allowing features to be added by various companies.[117] Lockheed Martin is working on upgrading the AN/AAR-56 Missile Launch Detector (MLD) to provide situational awareness and defensive Infrared Search and Track similar to the F-35's SAIRST.[118]
The current upgrade schedule is:
The Raptor is designed with a lifespan of 30 years and 8000 flight hours, but investigations are being made for upgrades to extend this.[120][121]
The F-22 Raptor is a fifth generation fighter that is considered a fourth-generation stealth aircraft by the USAF.[122] Its dual afterburning Pratt & Whitney F119-PW-100 turbofans incorporate pitch axis thrust vectoring, with a range of ±20 degrees. The maximum thrust is classified, though most sources place it at about 35,000 lbf (156 kN) per engine.[123] Maximum speed, without external weapons, is estimated to be Mach 1.82 in supercruise mode,[124] as demonstrated by General John P. Jumper, former US Air Force Chief of Staff, when his Raptor exceeded Mach 1.7 without afterburners on 13 January 2005.[125] With afterburners, it is "greater than Mach 2.0" (1,317 mph, 2,120 km/h). Former Lockheed chief test pilot Paul Metz stated that the Raptor has a fixed inlet, as opposed to variable intake ramps, and that the F-22 has a greater climb rate than the F-15, despite the F-15's higher thrust-to-weight ratio of 1.2:1 (the F-22 has a ratio closer to 1:1).[126] The US Air Force claims that the Raptor cannot be matched by any known or projected fighter types,[7] and Lockheed Martin claims: "the F-22 is the only aircraft that blends supercruise speed, super-agility, stealth and sensor fusion into a single air dominance platform."[127]
The ability of airframes to withstand both stress and heat is a major design factor, thus the F-22 makes use of many polymers; however, as some of the materials are a significant health risk to personnel, technicians require protective equipment such as eye protection, respirators and gloves to work on the aircraft.[128] The use of internal weapons bays allows the aircraft to maintain a comparatively higher performance while carrying a heavy payload over many other aircraft due to a lack of drag from external stores. It is one of only a few of aircraft that can supercruise, sustained supersonic flight without the use of afterburners, lowering fuel usage. The F-22 can intercept time-critical or rapidly moving targets that a subsonic aircraft would not have the speed to follow and an afterburner-dependent aircraft would lack fuel to reach.[129]
The F-22 is highly maneuverable, at both supersonic and subsonic speeds. It is extremely departure-resistant,[130] enabling it to remain controllable at extreme pilot inputs. The Raptor's thrust vectoring nozzles allow the aircraft to turn tightly, and perform extremely high alpha (angle of attack) maneuvers such as the Herbst maneuver (or J-turn), Pugachev's Cobra,[126] and the Kulbit.[126] The F-22 is also capable of maintaining a constant angle of attack of over 60°, yet still having some control of roll.[126][131] During June 2006 exercises in Alaska, F-22 pilots demonstrated that cruise altitude has a significant effect on combat performance, and routinely attributed their altitude advantage as a major factor in achieving an unblemished kill ratio against other US fighters and 4th/4.5th generation fighters.[132]
The F-22's avionics include BAE Systems E&IS radar warning receiver (RWR) AN/ALR-94,[133] AN/AAR 56 Infra-Red and Ultra-Violet MAWS (Missile Approach Warning System) and the Northrop Grumman AN/APG-77 Active Electronically Scanned Array (AESA) radar. The AN/ALR-94 is a passive receiver system to detect radar signals; composed of more than 30 antennas blended into the wings and fuselage that provide all around coverage. It was described by Tom Burbage, former F-22 program head at Lockheed Martin, as "the most technically complex piece of equipment on the aircraft." It has a greater range (250+ nmi) than the radar, allowing the F-22 to limit its own radar emissions to maximise stealth. As a target approaches, the receiver can cue the AN/APG-77 radar to track the target with a narrow beam, which can be as focused down to 2° by 2° in azimuth and elevation.[134]
The AN/APG-77 radar, designed for air superiority and strike operations, features a low-observable, active-aperture, electronically-scanned array that can track multiple targets in any weather. The AN/APG-77 changes frequencies more than 1,000 times per second to lower interception probability. Additionally, radar emissions can be focused in an electronic-attack capability to overload enemy sensors.[135][136]
The radar's information is processed by two Raytheon Common Integrated Processor (CIP)s. Each CIP can process 10.5 billion instructions per second and has 300 megabytes of memory. Information can be gathered from the radar and other onboard and offboard systems, filtered by the CIP, and offered in easy-to-digest ways on several cockpit displays, enabling the pilot to remain on top of complicated situations. The F-22s avionics software has some 1.7 million lines of code, the majority involving processing data from the radar.[137] The radar has an estimated range of 125–150 miles, though planned upgrades will allow a range of 250 miles (400 km) or more in narrow beams.[132] In 2007, tests by Northrop Grumman, Lockheed Martin, and L-3 Communications enabled the AESA system of a Raptor to act like a WiFi access point, able to transmit data at 548 megabits per second and receive at gigabit speed; this is far faster than the Link 16 system used by US and allied aircraft, which transfers data at just over 1 Mbit/s.[138]
The F-22 has a threat detection and identification capability comparative with the RC-135 Rivet Joint.[132] The F-22's stealth allows it to safely operate far closer to the battlefield, compensating for the reduced capability.[132] The F-22 is capable of functioning as a "mini-AWACS", however the radar is less powerful than dedicated platforms such as the E-3 Sentry.[126] The F-22 allows its pilot to designate targets for cooperating F-15s and F-16s, and determine whether two friendly aircraft are targeting the same aircraft.[126][132] This radar system can sometimes identify targets "many times quicker than the AWACS".[132] The radar is capable of high-bandwidth data transmission; conventional radio "chatter" can be reduced via these alternative means.[132] The IEEE-1394B data bus developed for the F-22 was derived from the commercial IEEE-1394 "FireWire" bus system.[139] Sensor fusion combines data from all onboard and offboard sensors into a common view to prevent the pilot from being overwhelmed.[140]
In a critical article former Navy Secretary John Lehman wrote "[a]t least [the F-22s] are safe from cyberattack. No one in China knows how to program the '83 vintage IBM software that runs them."[141] Former Secretary of the USAF Michael Wynne blamed the use of the DoD's Ada as a reason for cost overruns and schedule slippages on many major military projects, including the F-22 Raptor.[142] The F-22 uses the INTEGRITY-178B operating system from Green Hills Software, which is also used on the F-35, several commercial airliners and the Orion Crew Exploration Vehicle.[143]
The F-22 uses a glass cockpit with no analog flight instruments.[144] A side-stick controller and two throttles are the main flight controls. The stick is force sensitive and has limited movement. The cockpit interior lighting is fully night-vision goggle compatible. The monochrome head-up display by GEC (which has since become BAE Systems) offers a wide field of view and serves as a primary flight instrument for the pilot; information is also displayed upon six color liquid crystal display (LCD) panels.[144]
The integrated control panel (ICP) is a keypad system for entering communications, navigation, and autopilot data. Two 3 × 4 in (7.6 × 10 cm) up-front displays located around the ICP are used to display integrated caution advisory/warning data, communications, navigation and identification (CNI) data[citation needed] and also serve as the stand-by flight instrumentation group and fuel quantity indicator.[145] The stand-by flight group displays an artificial horizon, for basic instrument meteorological conditions. The 8 × 8 in (20 × 20 cm) primary multi-function display is located under the ICP, and is used for navigation and situation assessment.[145] Three 6.25 × 6.25 in (15.9 × 15.9 cm) secondary multi-function displays are located around the PMFD for tactical information and stores management.[145]
The canopy is approximately 140 inches long, 45 inches wide, and 27 inches tall; it lacks a canopy bow for improved vision. An iridium-tin oxide coating gives the canopy a gold color and reflects radar waves.[146] The ejection seat is a version of the ACES II (Advanced Concept Ejection Seat) commonly used in USAF aircraft, with a center-mounted ejection control. Improvements over the previous models include an active arm restraint system to reduce injury.
The life support system integrates critical components to sustain the pilot, such as the on-board oxygen generation system (OBOGS), and a breathing regulator/anti-g valve that controls flow and pressure to the mask and garments. The pilot's protective garments are designed for chemical/biological/cold-water immersion protection, to counter g-forces and high altitudes, and provide thermal relief. The helmet incorporates active noise reduction for hearing protection. Suspicions regarding the performance of the OBOGS and life support equipment have been raised by several crashes.[147]
The Raptor has three internal weapons bays on the bottom and sides of the fuselage.[148] It can carry six compressed carriage medium range missiles[149] in the center bay and one short range missile in each of the two side bays. Four of the medium range missiles can be replaced with two bomb racks that can each carry one medium-size bomb or four small diameter bombs.[150] Carrying missiles and bombs internally maintains its stealth capability and maintains lower drag resulting in higher top speeds and longer combat ranges. Launching missiles requires opening the weapons bay doors for less than a second, while the missiles are pushed clear of the airframe by hydraulic arms. This reduces the Raptor's chance of detection by enemy radar systems due to launched ordnance and also allows the F-22 to launch long range missiles while maintaining supercruise.[151] The F-22 can also carry air-to-surface weapons such as bombs with Joint Direct Attack Munition (JDAM) guidance and the Small-Diameter Bomb, but cannot self-designate for laser-guided weapons.[152] Air-to-surface ordnance is limited to 2,000 lb (compared to 17,000 lb of F/A-18).[153] The Raptor has an M61A2 Vulcan 20 mm cannon in the right wing root. The M61A2 carries 480 rounds; enough ammunition for approximately five seconds of sustained fire. The opening for the cannon's firing barrel is covered by a door when not in use to maximise stealth.[154] The F-22 has been able to close to gun range in training dogfights while avoiding detection.[126]
The Raptor's very high sustained cruise speed and operational altitude add significantly to the effective range of both air-to-air and air-to-surface munitions. This gives it a 40% greater employment range for air to air missiles than the F-35.[155] The USAF plans to procure the AIM-120D AMRAAM, reported to have a 50% increase in range compared to the AIM-120C. While specific figures remain classified, it is expected that JDAMs employed by F-22s will have twice or more the effective range of munitions dropped by legacy platforms.[156] In testing, a Raptor dropped a 1,000 lb (450 kg) JDAM from 50,000 feet (15,000 m), while cruising at Mach 1.5, striking a moving target 24 miles (39 km) away.[157]
While the F-22 typically carries its weapons internally, the wings include four hardpoints, each rated to handle 5,000 lb (2,300 kg). Each hardpoint has a pylon that can carry a detachable 600 gallon fuel tank or a launcher holding two air-air missiles. However, the use of external stores has a detrimental effect on the F-22's stealth, maneuverability and speed. The two inner hardpoints are "plumbed" for external fuel tanks; the hardpoints can be jettisoned in flight so the fighter can maximise its stealth after exhausting external stores.[158] A stealth ordnance pod and pylon is being developed to carry additional weapons internally.[159]
The stealth of the F-22 is due to a combination of factors, including the overall shape of the aircraft, the use of radar absorbent material (RAM), and attention to detail such as hinges and pilot helmets that could provide a radar return.[160] However, reduced radar cross section is one of five facets of presence reduction addressed in the designing of the F-22. The F-22 was designed to disguise its infrared emissions, reducing the threat of infrared homing ("heat seeking") surface-to-air or air-to-air missiles, including its flat thrust vectoring nozzles.[161] The aircraft was designed to be less visible to the naked eye; radio, heat and noise emissions are equally controlled.[160]
The F-22 apparently relies less on maintenance-intensive radar absorbent material and coatings than previous stealth designs like the F-117. These materials caused deployment problems due to their susceptibility to adverse weather conditions.[162] Unlike the B-2, which requires climate-controlled hangars, the F-22 can undergo repairs on the flight line or in a normal hangar.[162] Furthermore, the F-22 has a "Signature Assessment System", which presents warning indicators when normal wear-and-tear degrades the aircraft's radar signature to the point of requiring substantial repair work.[162] The exact radar cross section (RCS) remains classified; however, in early 2009 Lockheed Martin released information on the F-22, indicating it to have a RCS (from certain angles) of −40 dBsm – the equivalent radar reflection of a "steel marble".[163] Maintenance of the F-22's stealth features decreases the mission capable rate to approximately 62–70%.[N 2]
| Aircraft | Radar cross section (estimate) |
|---|---|
| Sukhoi Su-30MKI | 20 square metres[165] |
| Dassault Rafale | 2 square metres[166] |
| Eurofighter Typhoon | 1 square metre[167] |
| Sukhoi Su-35BM | 1 square metre[168] |
| Lockheed F-117 Nighthawk | 0.025 square metres[166] |
| Lockheed Martin F-22 Raptor | 0.0001 square metres[169] |
The effectiveness of the stealth characteristics is difficult to gauge. The RCS value is a restrictive measurement of the aircraft's frontal or side area from the perspective of a static radar. As soon as the F-22 maneuvers, it exposes a completely different set of angles and surface area, increasing visibility. Furthermore, the use of stealth contouring and radar absorbent material are chiefly effective against high-frequency radars, usually found on other aircraft. Low-frequency radars, employed by weather radars and ground warning stations, are alleged to be less affected by stealth characteristics and are more capable of detecting aircraft.[170][171] The result of these faint and fleeting radar contacts is that while defenders could become aware of the presence of a stealth aircraft, means of interception cannot be reliably vectored in to shoot down the aircraft.[172]
The F-22 also includes measures designed to minimize its detection by infrared, including special paint and active cooling of leading edges to deal with the heat buildup encountered during supercruise flight.[173]
The YF-22 was originally given the unofficial name "Lightning II", after the World War II fighter P-38, by Lockheed, which persisted until the mid-1990s when the USAF officially named the aircraft "Raptor". The aircraft was also briefly dubbed "SuperStar" and "Rapier".[174] The F-35 later received the Lightning II name on 7 July 2006.[175] In September 2002, Air Force leaders changed the Raptor's designation to F/A-22. The new designation, mimicking the Navy's F/A-18 Hornet, was intended to highlight plans for a ground-attack capability amid intense debate over the relevance of expensive air-superiority jets. The F-22 designation was reinstated on 12 December 2005, when the aircraft entered service.[7][176]
Flight testing of the F-22 began in 1997. Raptor 4001 was retired and sent to Wright-Patterson AFB to be fired at for testing the fighter's survivability. Usable parts of 4001 would be used to make a new F-22. Another engineering and manufacturing development (EMD) F-22 was also retired and likely to be sent to be rebuilt. A testing aircraft was converted to a maintenance trainer at Tyndall AFB.[177]
In May 2006, a released report documented a problem with a forward titanium boom on the aircraft. The problem was caused by a manufacturing defect in the heat-treating, making the boom less ductile than specified and potentially shortening the lives of roughly the first 80 F-22s. Modifications were implemented to restore full life expectancy.[178][179]
On 15 December 2005 the USAF announced that the Raptor had reached its Initial Operational Capability (IOC).[180] During Exercise Northern Edge in Alaska in June 2006, 12 F-22s of the 94th FS downed 108 adversaries with no losses in simulated combat exercises.[22] In two weeks of exercises, the Raptor-led Blue Force amassed 241 kills against two losses in air-to-air combat; neither Blue Force loss was an F-22. Shortly after was Red Flag 07-1 in February 2007. Fourteen F-22s of the 94th FS supported Blue Force strikes and undertook close air support sorties themselves. Against superior numbers of Red Force Aggressor F-15s and F-16s, 6-8 F-22s maintained air dominance throughout. No sorties were missed because of maintenance or other failures, and only one Raptor was judged lost against the opposing force's defeat.[N 3] F-22s also provided airborne electronic surveillance.[181]
While attempting its first overseas deployment to the Kadena Air Base in Okinawa, Japan, on 11 February 2007, six F-22s flying from Hickam AFB, Hawaii experienced multiple computer failures while crossing the 180th meridian of longitude (the International Date Line). The failures included navigation and communication.[182] The fighters were able to return to Hawaii by following tanker aircraft. Within 48 hours, the error was resolved and the journey resumed.[183] 90th Fighter Squadron performed the first F-22 NORAD interception of two Russian Tu-95MS 'Bear-H' bombers over Alaska, on 22 November 2007.[184] Since then, F-22s have also escorted probing Tu-160 "Blackjack" strategic bombers.[185]
On 12 December 2007, General John D.W. Corley, USAF, Commander of Air Combat Command, officially declared the F-22s of the integrated active duty 1st Fighter Wing and Virginia Air National Guard 192d Fighter Wing fully operational, three years after the first Raptor arrived at Langley Air Force Base, Virginia.[186] This was followed from 13 to 19 April 2008 by an Operational Readiness Inspection (ORI) of the integrated wing in which it received an "excellent" rating in all categories while scoring a simulated kill-ratio of 221–0.[187] The first pair of Raptors assigned to the 49th Fighter Wing became operational at Holloman Air Force Base, New Mexico, on 2 June 2008.[188]
In December 2007, Secretary of the Air Force Michael Wynne requested that the F-22 be deployed to the Middle East; Secretary of Defense Gates rejected this option.[189] Time suggested part of the reason for it not being used in the 2011 military intervention in Libya may have been its high unit cost.[190]
On 28 August 2008, an unmodified F-22 from the 411th Flight Test Squadron performed in the first ever air-to-air refueling of an aircraft using synthetic jet fuel. The test was a part of a wider USAF effort to qualify aircraft to use the fuel, a 50/50 mix of JP-8 and a Fischer-Tropsch process-produced, natural gas-based fuel.[191] Then in 2011 a Raptor made a supersonic flght on a 50% mixture of biofuel derived from camelina.[192]
In 2009, a spokesperson for Lockheed-Martin stated the mission ready rate had improved from 62% in 2004 to 68% in 2009, and was predicted to reach 85% as the fleet reached 100,000 flight hours.[193] The Washington Post stated that between October 2008 and May 2009, 55 percent of the deployed F-22 fleet has been available.[194] Air Force Magazine responded to the Washington Post article, stating it was incorrect and that mission capable rates were climbing; by June 2009 they stood at 62.9%, compared to approximately 70% for the F-15 and F-16 aircraft.[195][196] In 2010, the Air Force Association stated the mission capable rate for the F-22 fleet was 70%.[197]
In July 2009, the Air Force reported that the F-22 requires more than 30 hours of maintenance for every flight hour, with the total cost per flight hour of $44,000.[194] The Office of the Secretary of Defense puts that figure at 34 hours of maintenance per flight hour at a cost of $49,808.[194] A Lockheed spokesman said, however, that the variable cost per flight hour is $19,000,[193] with a direct maintenance man hours per flight hour of 18.10 in 2008 and 20.48 in 2009.[193] The Pentagon requirement is for 12 hours of maintenance per flight hour.[193] The F-22 also reportedly encountered a critical failure every 1.7 hours.[N 4] The F-22 had required maintenance every 0.97 flight hours in 2004. This improved to 3.22 flight hours per maintenance event in production Lot 6 aircraft.[193]
Each Raptor requires a month-long packaged maintenance plan (PMP) after every 300 flight hours.[199] The aircraft's radar-absorbing metallic skin is a principal cause of maintenance – skin repairs account for more than half of all maintenance.[194] Another source of maintenance problems is that many components require custom hand-fitting and are not interchangeable.[194] The canopy visibility degrades more rapidly than expected, and, instead of the required 800 hours, refurbishments are at 331 flight hours on average.[194] Pentagon officials have responded that measuring flying costs for aircraft fleets that have not reached 100,000 flying hours is premature. Officials also stated that improvements have been made since 2008; and that the F-22 is on track to meet key performance measures by 2010.[194]
In January 2007, it was reported that the F-22 maintained a 97% sortie rate (flying 102 out of 105 tasked sorties) while amassing a 144-to-zero kill ratio during "Northern Edge" air-to-air exercises held in Alaska, the first large-scale exercise in which the Raptor participated. Lt. Col. Wade Tolliver, the squadron commander of the 27th FS commented: "the stealth coatings are not as fragile as they were in earlier stealth aircraft. It isn't damaged by a rain storm and it can stand the wear and tear of combat without degradation."[162] However, rain has caused "shorts and failures in sophisticated electrical components" when the Raptors were briefly posted to Guam.[200]
In its 2012 budget request the USAF cut F-22 flight training hours by one-third to reduce the operating costs of flying the aircraft.[201] The F-22 will continue in its role as an airshow demonstration aircraft and will be the only USAF solo aircraft demonstrator in 2012.[202]
During 2010–2011 periodic operational hazards surfaced regarding F-22 operations. In February 2010 the entire fleet was grounded due to rusting ejection seat rods.[203] In May 2011 the entire fleet was grounded; following the November 2010 crash near Elmendorf Air Force Base, Alaska the F-22 had been restricted to flying below 25,000 feet while the Honeywell oxygen generating system was inspected. After five incidents of pilots suffering from hypoxia and decompression,[204] General William M. Fraser III of Air Combat Command grounded the F-22 fleet indefinitely on 3 May 2011.[205][206] In June 2011, the investigation broadened across the life support systems,[207] and aircraft deliveries were stopped.[208]
In July 2011 the investigation suspected a scenario in which the pilots were poisoned by carbon monoxide from the engines while warming up the plane inside the hangars.[209] Tests on pilots have found other chemicals have been inhaled from the on-board oxygen generating system (OBOGS), including oil fumes and propane.[210][211]
In September 2011, the F-22 returned to flight with added pilot safety equipment and careful monitoring of crew and aircraft, while the investigation continued.[212][213] On 21 October 2011, Langley's F-22s were grounded after a suspected oxygen system problem;[214][215] Elmendorf-Richardson grounded their aircraft as well.[216] All aircraft were cleared to fly again on October 25.[217] In late October 2011, Lockheed Martin was awarded a $24M contract to find the cause of the oxygen system difficulty, as well as providing other sustainment functions.[218] In mid-December 2011, the Air Force said that there had been 14 episodes since September, when the planes returned to operation, in which pilots experienced "physiological incidents" which might have been caused by a lack of oxygen.[219]
The FB-22 was a proposed medium-range bomber for the USAF.[221] The FB-22 was projected to carry up to 30 Small Diameter Bombs to about twice the range of the F-22A, while maintaining the F-22's stealth and supersonic speed.[222] However, the FB-22 in its planned form appears to have been canceled with the 2006 Quadrennial Defense Review and subsequent developments, in lieu of a larger subsonic bomber with a much greater range.[223][224]
The X-44 MANTA, or multi-axis, no-tail aircraft, was a planned experimental aircraft based on the F-22 with enhanced thrust vectoring controls and no aerodynamic backup.[225] The aircraft was to be solely controlled by thrust vectoring, without featuring any rudders, ailerons, or elevators. Funding for this program was halted in 2000.[226]
The United States Air Force is the only operator of the F-22. It has ordered 187 aircraft with the last to be received in 2012.[227][228] It is operated by the following commands:
Because of the platform's relative immaturity due to its early operational status and low number of flight hours compared to other platforms, the F-22 has the highest accident rate of any USAF fighter aircraft in service. This rate is expected to go down as the Air Force gains more experience in operating the aircraft.[239]
In April 1992, the first YF-22 crashed while landing at Edwards Air Force Base, California. The test pilot Tom Morgenfeld escaped without injury. The cause of the crash was found to be a flight control software error that failed to prevent a pilot-induced oscillation.[240]
The first crash of a production F-22 occurred during takeoff at Nellis Air Force Base on 20 December 2004, in which the pilot ejected safely before impact.[241][242] The crash investigation revealed that a brief interruption in power during an engine shutdown prior to flight caused a malfunction in the flight-control system;[243] consequently the aircraft design was corrected to avoid the problem. All F-22s were grounded after the crash; operations resumed following a review.[244]
On 25 March 2009, an F-22 crashed 35 miles (56 km) northeast of Edwards Air Force Base during a test flight,[245] resulting in the death of Lockheed test pilot David P. Cooley.[194][246] An Air Force Materiel Command investigation found that Cooley momentarily lost consciousness during a high-G maneuver, then ejected when he found himself too low to recover. Cooley was killed during ejection by blunt-force trauma from the aircraft's speed and the windblast. The investigation found no issues with the F-22's design.[247]
On 16 November 2010, an F-22, based at Elmendorf, Alaska, lost contact with Air Traffic Control.[248] The aircraft was discovered to have crashed; the pilot, Captain Jeffrey Haney, did not survive.[249] The F-22 fleet was restricted to flying below 25,000 feet, before being grounded completely, while the accident was investigated.[250] During the summer of 2011, more wreckage from the crash site was recovered; the accident has been attributed to a malfunction in the bleed air system that shut down the aircraft's Environmental Control System (ECS) and On-Board Oxygen Generating System (OBOGS).[251] The OBOGS was apparently shut down automatically in response to an overheat condition detected by the main computer.[252] The accident review board, however, ruled the pilot was to blame for the accident, as he did not react properly and did not engage the emergency oxygen system,[253][254] even though part of the activation mechanism was improperly installed.[255]
In April 2007 The National Museum of the United States Air Force announced it had added EMD F-22A 91-4003 to its collection. It would later be put on display[256] in the space being occupied by a YF-22. The Museum publicly unveiled its F-22 display on 18 January 2008.[257]
Data from USAF,[7] F-22 Raptor Team web site,[258] Lockheed Martin,[259] Aviation Week,[132] Journal of Electronic Defense,[134] and Manufacturers' data[259][260]
General characteristics
Performance
Armament
Avionics
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