2012年9月23日星期日

Military of F-22 Raptor

On 1 August 2012, the director of operations for the Air Force's Air Combat Command Major General Charles Lyon said at a briefing at the Pentagon that the source of previously unexplained physiological incidents had been "determined with confidence." General Lyon pinpointed the upper pressure garment, oxygen delivery hoses, quick connection points and on occasion, the air filter canister, as root causes of previously unexplained physiological incidents in which some pilots complained of hypoxia-like symptoms. In addition to testing aircraft and associated equipment, the Air Force's investigative process also involved canvassing the F-22 communities to gauge pilot, maintainer and family member confidence in the aircraft's safety. General Lyon, however, added that there would undoubtably be physiological incidents in the future in the F-22 and in other aircraft, and that it was an associated risk in the operation of high-performance fighter aircraft. General Lyon said that the root causes of the issues with the F-22 remained unknown for such a long period of time were what caused concern to the Air Force.

On 24 July 2012, Defense Secretary Leon E. Panetta said he was satisfied the Air Force had identified the cause of hypoxia-like symptoms 12 F-22 pilots suffered, linking the incidents to a defect in the pilots' pressure garment vest. Pilots used the vest to combat G-forces generated flying the high-performance aircraft. The vest functioned by inflating to stop blood from pooling, which would cause pilots to black out during high-speed turns. The Air Force had found that a faulty valve caused the vest to inflate and remain inflated under conditions where it was not designed to inflate, thereby causing breathing problems for some pilots. The use of the garment had been suspended in June 2012 as part of the investigation into the source of hypoxia-like symptoms experienced by some pilots dating back to 2008. The problem had not been identified during initial F-22 testing. In addition, the Air Force removed a canister filter from the oxygen delivery system, and that has increased the volume of air flowing to pilots. The filter had been added as part of initial attempts to solve the issue. The Air Force was also looking at improving the oxygen delivery hose and its connections.

As a result of the findings and immediate changes, Secretary Panetta decided to lift flight restrictions that had been placed on the aircraft in May 2012 gradually. As of 24 July 2012, F-22s could resume long-duration flights for deployments, aircraft deliveries and repositioning of aircraft. Long duration flight routes would still be designed to pass near airfields. The Air Force also imposed an altitude restriction on the aircraft so pilots would not need to wear the pressure vest. Training sorties were to remain near runways until completion of the Air Force Scientific Advisory Board-recommended corrective actions. This was expected by the end of summer 2012. The Air Force was to notify Secretary Panetta when fixes were finished with the pressure vest and related cockpit life support components. Pending successful completion of associated testing and NASA's independent analysis, Secretary Panetta could decide to return the F-22 fleet status to normal operations.

The F-22 program is developing the next-generation air superiority fighter for the United States Air Force to counter emerging worldwide threats. The F-22 Raptor is designed to ensure that America's armed forces retain air dominance. This means complete control of the airspace over an area of conflict, thereby allowing freedom to attack and freedom from attack at all times and places for the full spectrum of military operations. Air dominance provides the ability to defend our forces from enemy attack and to attack adversary forces without hindrance from enemy aircraft.

During the initial phases of deployment into an area of conflict, the first aircraft to arrive are the most vulnerable because they face the entire warfighting capability of an adversary. The F-22's state-of-the-art technology, advanced tactics, and skilled aircrew will ensure air dominance from the outset of such situations. It is designed to penetrate enemy airspace and achieve a first-look, first-kill capability against multiple targets. The F-22 is characterized by a low-observable, highly maneuverable airframe; advanced integrated avionics; and aerodynamic performance allowing supersonic cruise without afterburner.

The F-22 is an air dominance fighter with much-improved capability over current Air Force aircraft. It is widely regarded as the most advanced fighter in the world, combining a revolutionary leap in technology and capability with reduced support requirements and maintenance costs. It will replace the F-15 as America's front-line, air superiority fighter, with deliveries to operational units in 2005.

From the inception of the battle, the F-22's primary objective will be to establish absolute control of the skies through the conduct of counterair operations. The fighter also has an inherent precision ground attack capability. The F-22 is capable of carrying existing and planned medium and short range air-to-air missiles in internal bays. The F-22 will also have an internal 20-mm cannon and provisions for carrying precision ground attack weapons.

The F-22 Raptor is being developed to counter lethal threats posed by advanced surface-to-air missile systems and next generation fighters equipped with launch-and-leave missiles. The Air Force faces two challenges to providing air dominance with its current fleet of fighter aircraft. First, other nations continuously improve their aerial warfare capability by fielding newer, faster, more maneuverable aircraft, such as the MiG-29, Su-35, Rafale, Gripen, and Eurofighter. Second, potential adversaries have added sophisticated air defenses built around surface-to-air missiles that can target conventional aircraft more accurately and at greater distances than in the past. The F-22 has the stealth, speed, and maneuverability to overcome these challenges and ensure air dominance over any battlefield.

The F-22's combination of stealth, integrated avionics, maneuverability and supercruise will give Raptor pilots a first-look, first-shot, first-kill capability against the aircraft of any potential enemy. The F-22 is designed to provide not just air superiority, but air dominance, winning quickly and decisively with few US casualties. The Raptor also has an inherent air-to-ground capability.

The F-22 will provide a first-look, first-shot, first-kill capability through the use of reduced observables and advanced sensors. To decrease the reaction time of enemy threats, increased supersonic cruise, and maneuverability goals have been set. The F-22's avionics suite is a highly integrated system maximizing performance to allow the pilot to concentrate on the mission, rather than on managing the sensors as in current fighters. To improve operations from battle-damaged runways, the F-22 offers significantly reduced takeoff and landing distances, as compared to today's frontline fighters. A greatly increased combat radius, using internal fuel only, will give F-22 pilots the capability to engage the enemy over his territory and support long-range air-to-ground assets such as the F-15E. The F-22 will also bring a precision ground attack capability to the battlefield. In addition to greater lethality and survivability, the F-22 design calls for higher reliability, maintainability, and sortie generation rates than the aircraft it will replace. The design goal for all areas is a 100 percent improvement over the F-15 weapon system.
The F-22 is 62 feet, 1 inch long, it has a wingspan of 44 feet 6 inches, and stands 16 feet, 5 inches tall. The F-22A is a single seat aircraft.

"Agility" is the ability of the F-22 pilot to point and shoot with his aircraft, pirouetting, and facing the enemy with his weapons at all speeds. The F-22 pilot can maintain control of the aircraft at speeds as low as that of a Piper Cub or at very high supersonic speeds. Because of the F-22's sophisticated aero-design and high thrust-to-weight ratio, it can easily outmaneuver all current and projected threat aircraft, both at medium and high altitudes.

"Supercruise" is the term given to the capability of sustaining supersonic speeds for long periods of time. Conventional fighters, while capable of supersonic flight, can only sustain these speeds for relatively short periods as the result of excessively high fuel consumption using afterburner. The F-22's engines produce more thrust than any current fighter engine, especially in military (non-afterburner) power. Called "supercruise," this characteristic allows the F-22 to efficiently cruise at supersonic airspeeds without using afterburners. The F-22's engine is expected to be the first to provide the ability to fly faster than the speed of sound for an extended period of time without the high fuel consumption characteristic of aircraft that use afterburners to achieve supersonic speeds. It is expected to provide high performance and high fuel efficiency at slower speeds as well. This capability greatly expands the F-22's operating envelope in both speed and range over current fighters that must use afterburner to operate at supersonic speeds. The F-22 can cruise supersonically without afterburner and, therefore, can sustain these speeds for long periods. The enemy must react to any intruder and that reaction time to detect, aim weapons and launch, is severely reduced when the intruder is moving fast. At supercruise speeds, the F-22 (and its pilot) becomes less vulnerable to enemy missiles and aircraft simply because they cannot react fast enough.

The industry team of Lockheed Martin and Boeing is working with the U.S. Air Force and Pratt & Whitneyto develop the F-22 to replace the F-15 as America's front line air dominance fighter. The Critical Design Review (CDR) of the F-22 and the Initial Production Readiness Review (IPRR) of the F119 engine were completed in February 1995. The Air Force confirmed that the program was ready to proceed to fabrication and assembly of EMD aircraft. First flight of an EMD aircraft took place in September 1997. Low-rate initial production began in 1999. The F-22A Raptor achieved Initial Operational Capability [IOC] on 15 December 2005.

Prior to its selection as winner of what was then known as the Advanced Tactical Fighter (ATF) competition, the F-22 team conducted a 54-month demonstration/validation (dem/val) program. The effort involved the design, construction, and flight testing of two YF-22 prototype aircraft. The dem/val phase of the program was completed in December 1990. Two prototype engine designs, the Pratt & Whitney YF119-PW-100 and the General Electric YF120-GE-100, also were developed and tested during the program. The Pratt & Whitney F119 was selected by the Air Force to power the F-22. Much of the dem/val work was performed at Lockheed (now Lockheed Martin) in Burbank, Calif.; at General Dynamics (now Lockheed Martin Tactical Aircraft Systems) in Fort Worth, Texas, at Boeing in Seattle, Wash. The prototypes were assembled in Lockheed's Palmdale, CA, facility and made their maiden flight from there. Since that time, Lockheed Martin's program management and aircraft assembly operations have moved to Marietta, GA., for the EMD and production phases.

The fast, agile, and stealthy F-22 began to take over the air dominance role first with Air Combat Command. Once testing and evaluations were successfully completed on the F/A-22 Raptor, it made its debut into the Air Force arsenal in 2005 as a replacement for the F-15 Eagle. The F/A-22's operational utility was tested and evaluated at Air Combat Command's 422nd Test and Evaluation Squadron at Nellis Air Force Base, Nev.

    The Block 10 Initial Operational Capability configuration, to be fielded this year, will be multirole, with the option of four AMRAAMs being replaced by GBU-32 JDAMs. This provides an analogous deep-strike capability to the F-117A, but is more survivable.
    The Block 20 configuration is the baseline for the Global Strike Task Force (GSTF) fleet, and will include JSF common radar modules, a dedicated high-speed radar processor, and COTS technology CIP processors. The GBU-39/40 Small Diameter Bomb is introduced in the Block 20 aircraft by 2007, together with high resolution SAR radar modes, improved radar ECCM, two way voice and data MIDS/Link-16 capability, improved crew station software, and improved electronic countermeasures.
    The Block 30 configuration, planned for 2008-2011, extends the growth seen in the Block 20. Side-looking radar arrays provide a significant ISR capability in the aircraft along with enhancements to provide full Wild Weasel air defence suppression and time-critical target engagement capabilities. A Satcom terminal will provide continuous network connectivity during deep-strike profiles.
    The post-2011 Block 40 aircraft is intended to be the definitive Global Strike configuration, with incremental enhancements to Block 30 additions providing full sensor networking, range enhancements, integrated ISR capabilities, and a Helmet Mounted Display similar to the JSF.
    Longer term planning for a Block 50 envisages an Electronic Attack variant, replacing the lost EF-111A Raven. A stealthy stores pod for JDAM and SDB is under development to enable carriage on external pylons. As a strike aircraft the F/A-22A will have similar internal payloads to the JSF, but will be vastly more survivable due to better stealth.

On Sept. 17, 2002 Air Force Chief of Staff Gen. John P. Jumper announced a change in the designation of the F-22 Raptor to F/A-22 at the 2002 Air Force Association National Convention. The change is meant to more accurately reflect the aircraft's multimission roles and capabilities in contemporary strategic environments. However, the designation reverted to F-22 in December 2005.

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