Fifth generation jet fighter

A fifth-generation jet fighter is a fighter aircraft classification used in the United States encompassing the most advanced generation of fighter aircraft. Fifth-generation aircraft are the most advanced as of 2011, designed to incorporate numerous technological advancements over the class similarly dubbed fourth generation, including all-aspect stealth even when armed, Low Probability of Intercept Radar (LPIR), high-performance air frames, advanced avionics features, and highly integrated computer systems capable of networking with other elements within the theater of war in order to achieve an advantage in situational awareness. The only currently combat-ready fifth-generation fighter, the Lockheed Martin F-22 Raptor, entered service with the U.S. Air Force in 2005.

History
Previous generation stealth aircraft, such as the B-2 Spirit and F-117 Nighthawk, lacked LPI Active Electronically Scanned Array (AESA) radars, and LPI radio networks, and were thus limited to attacking ground targets, because use of radar to engage other aircraft would have revealed the aircraft's position.

Current status
Currently the only combat ready fifth generation jet fighter is the F-22 Raptor. US fighter manufacturer Lockheed Martin uses "fifth generation fighter" to describe the F-22 and F-35 fighters, with the definition including "advanced stealth", "extreme performance", "information fusion" and "advanced sustainment". Their definition does not include super cruise capability, which has typically been associated with the more advanced modern fighters, but which the F-35 lacks. Lockheed Martin attempted to trademark the term "5th generation fighters" in association with jet aircraft and structural parts thereof, and has a trademark to a logo with the term.

Critics and alternate definitions
The use of the term fifth generation fighter has been criticized by companies whose products do not conform to these particular specifications, such as Boeing and Euro fighter as well as by other commentators, such as Bill Sweetman: "...it is misleading to portray the F-22 and F-35 as a linear evolution in fighter design. Rather, they are a closely related pair of outliers, relying on a higher level of stealth as a key element of survivability - as the Lockheed YF-12 and Mikoyan MIG-25, in the 1960s, relied on speed and altitude." The United States Navy and Boeing have placed the Boeing F/A-18E/F Super Hornet in a "next generation" fighter category along with the F-22 and F-35, as the Super Hornet has a "fifth generation" AESA radar, modest radar cross-section (RCS) reductions and sensor fusion. A senior USAF pilot has complained about fifth generation claims for the Super Hornet: "The whole point to fifth generation is the synergy of stealth, fusion and complete situational awareness. The point about fifth generation aircraft is that they can do their mission anywhere - even in sophisticated integrated air defense [IADS] environments. If you fly into heavy IADS with a great radar and sensor fusion, but no stealth, you will have complete situational awareness of the guy that kills you." Michael “Ponch” Garcia of Raytheon has said that the addition of his company's AESA radars to the Super Hornet provides "90 percent of your fifth-generation capability at half the cost."

Apparently in response to the use of the "fifth generation" term, Eurofighter has made a fifth generation checklist placing different weights on the various capabilities, and arguing that the application of the label to strike aircraft such as Lockheed-Martin's F-35 is ill advised, and even inconsistent with the aircraft's specifications. Meanwhile, Eurofighter go on to refer to Link 16 capability, an already well established system, as fulfilling a requirement for 'net-enabled operations' seemingly assigning reduced importance to maintaining low observability of such operations. In the same article Eurofighter GmbH appear to acknowledge the remarkable performance of Lockheed Martin's F-22 aircraft, while demonstrating that labels as simple as "fifth generation" may easily be devised to serve the interests of the writer.

Developments
In the late 1980s, the Soviet Union outlined a need for a next-generation aircraft to replace 4th generation fighter aircraft: MiG-29 Fulcrum and Su-27 Flanker in frontline service. Two projects were proposed to meet this need, the 4.5th generation fighter aircraft: Su-47 Berkut and the MiG-1.44 Flatpack (although later modernized MiG-35 to 4.5th generation fighter). In 2002, Sukhoi was chosen to lead the design for the new combat aircraft. The 5th generation fighter aircraft - Sukhoi PAK FA (T-50) will incorporate technology from both the Su-47 and the MiG 1.44 and when fully developed is intended to replace the MiG-29 and Su-27 in the Russian inventory and serve as the basis of the Sukhoi/HAL FGFA project being developed with India. A fifth generation jet fighter, it is designed to directly compete with the American F-22 Raptor and American/British F-35 Lightning II. The Sukhoi PAK FA performed its first flight January 29, 2010. Russia is now constructing a new stealth lightweight multirole fighter - MiG-LMFS (aka Projekt 1.27, MiG-1.27) by Mikoyan aircraft manufacturer. This jet fighter is based on the cancelled MiG 1.44.

By late 1990s, several Chinese fifth generation fighter programs, grouped under the program codename J-XX or XXJ, were identified by western intelligence sources. PLAAF officials have confirmed the existence of such a program, which they estimate will enter service between 2017-2019. Nevertheless, the United States has predicted that it may possess as much as 20 times more "advanced stealth fighters" than the Chinese by 2020. By late 2010, it had emerged that two prototypes (#2001 & 2002) of the Chengdu J-20 had been constructed and were undergoing high-speed taxi trials.. The J-20 made its first flight on 11 January 2011.

India is also developing Medium Combat Aircraft, a Twin-engined 5th generation stealth multirole fighter apart from Sukhoi/HAL FGFA project being developed with Russia. The main purpose of this aircraft is to replace the aging SEPECAT Jaguar & Dassault Mirage 2000. Unofficial design work on the MCA has been started.

Common design elements
In order to minimize their RCS, all fifth generation fighters use chines instead of standard leading edge extensions and lack canards, though the Sukhoi PAK FA T-50 has engine intake extensions that seem to function somewhat like canards and the Chengdu J-20 designers have chosen the agility enhancements of canards in spite of their poor stealth characteristics. They all have twin canted vertical tails also to minimize side RCS. Most fifth generation fighters with super maneuverability achieve it through thrust vectoring.

They all have internal weapon bays in order to avoid high RCS weapon pylons, but they all have external hard points on their wings for use on non-stealthy missions, such as the external fuel tanks the F-22 carries when deploying to a new theater.

All fifth generation fighters have a high percentage of composite materials, in order to reduce RCS and weight.

All revealed fifth generation fighters leverage commercial off-the-shelf main processors to directly control all sensors to form a consolidated view of the battlespace with both onboard and networked sensors, while previous generation jet fighters used federated systems where each sensor or pod would present its own readings for the pilot to combine in his own mind a view of the battlespace. This means that while the F-22A was physically delivered without synthetic aperture radar or situational awareness infra-red search and track it will gain these functions later through software upgrades. However any flaw in these huge software systems can knock out supposedly unrelated aircraft systems and the complexity of a software defined aircraft can lead to a software crisis with additional costs and delays.

Sukhoi calls their expert system for sensor fusion the artificial intelligence of the PAK-FA.

Situational awareness dominance
Sensor fusion and automatic target tracking are projected to give the fifth generation jet fighter pilot a view of the battlespace superior to that seen by AWACS aircraft that may be forced back from the front lines by increasing threats. Therefore tactical control could be shifted forwards to the pilots in the fighters.
However the more powerful sensors, such as AESA radar which is able to operate in multiple modes at the same time, may present too much information for the single pilot in the F-22, F-35 and T-50 to adequately use. The Sukhoi/HAL FGFA offers a return to the two-seat configuration common in fourth generation strike fighters.