
saludos,
Falcon V8
LOS GRAVES PROBLEMAS DEL F-22 CONTINÚAN.
La Fuerza Aérea estadounidense continúa investigando en busca de las razones que provocan el “misterio de la hipoxia” que afecta a los pilotos del caza de última generación F-22 durante el vuelo provocándoles la asfixia. El último caso tuvo lugar la pasada semana en Hawái, si bien el piloto logró aterrizar el aparato.
Sustituidos los trajes antiG de los pilotos, a los que inicialmente se atribuyó el problema, ante la persistencia de los problemas de oxigenación los ojos se pusieron en el sistema de oxígeno de los Raptor, si bien sigue sin determinarse donde está el origen y por tanto sin darse con la solución, siendo varios los pilotos de la Fuerza Aérea de EEUU que se niegan a volar el aparato. Actualmente todos los vuelos de prueba se están llevando a cabo cerca de lugares de potencial aterrizaje para permitir una maniobra de emergencia en caso de que se produzcan nuevos incidentes.
El problema se convirtió en noticia tras el accidente del 16 de noviembre de 2010, cuando uno de los pilotos del F22, el capitán Jeffrey Haney, murió en un Raptor durante un vuelo de adiestramiento. Según las investigaciones posteriores, el avión se precipitó a tierra sin reacción del piloto, estableciéndose la hipoxia de su tripulante como causa del accidente. El Air Combat Command, informaba entonces que se habían registrado casos de hipoxia en diversos grados, lo que determinó que toda la flota de Raptor fuera puesta en tierra durante meses, periodo durante el cual el Consejo Científico de la USAF realizó una exhaustiva revisión de todos los sistemas de protección de vida (aircraft's life support systems) de la aeronave, intentado identificar la causa y resolver un fallo que, todo apunta, persiste a día de hoy.
F-22 Oxygen Fix Expected By End of Year
Jul. 31, 2012
A faulty valve on the pressurized vests worn by F-22 pilots will be replaced by the end of the year, a move aimed at solving pilots’ complaints of nausea and dizziness while flying the stealth fighter.
The valve connects the plane’s onboard oxygen supply to a tube that inflates the vest, protecting pilots from high-G forces. But a flaw in the valve caused the vests to be constantly inflated, even at lower altitudes when they weren’t needed, said Maj. Gen. Charles Lyon, the director of operations for Air Combat Command. The continuous pressure on the pilots’ chests caused symptoms of oxygen deficiency, or hypoxia.
“It restricts his breathing, it restricts his ability to do normal inhalation and exhalation. ... The pressurization schedule in the F-22 inflates prematurely, so we removed this,” Lyon said at a Pentagon briefing Tuesday.
Within a month, the Air Force will begin testing a new valve that will provide more tension and will restrict the airflow to the pressure vest until needed, he said.
The F-22s oxygen problems forced the Air Force to ground the entire fleet for four months last year. The planes returned to flight in September, but more complaints from pilots followed. On May 15, Defense Secretary Leon Panetta ordered the planes to fly at low altitude and within a safe landing distance of runways until the cause of the problem was identified.
Pilots were directed to stop wearing the pressurized vests in June, as investigative teams searched for clues.
Last week, a Pentagon spokesman announced that the valve on the vest was at least partly to blame. Within days, the Air Force deployed 12 Raptors of the 1st Fighter Wing at Joint Base Langley-Eustis, Va., to Kadena Air Base, Japan. The pilots stayed close to landing strips along the way, including stops at Joint Base Elmendorf-Richardson, Alaska, and Joint Base Pearl Harbor-Hickam, Hawaii, Lyon said.
“I have high confidence that we have eliminated the major contributing factors,” he said.
The Air Force has been under intense pressure to solve the F-22 problem, which first came to light after the November 2010 crash that killed Capt. Jeff Haney near Joint Base Elmendorf-Richardson. An accident investigation board found that Haney did not activate theF-22’s emergency oxygen system quickly enough or recover from a dive as he struggled to breathe. Air Force Chief of Staff Gen. Norton Schwartz has said Haney faced a “complex emergency.”
Lyon said there is no evidence that Haney’s crash was connected to the faulty valve now being replaced.
The Air Force first used pressurized vests in 1992, after years of testing. The vests worn by F-15 and F-16 pilots received a low-pressure supply of oxygen that would increase only in the event of a rapid decompression to protect the pilots’ lungs. But by the mid-2000s, the Air Force decided they were no longer needed in F-15s and F-16s. The vests were used in F-22s because they provided the pressure needed to help pilots breathe while flying at higher altitudes and under greater G forces, Lyon said.
Late last year, an Air Force Scientific Advisory Board investigation into the F-22 found that testing of the vest was “rudimentary” and didn’t identify the excessive restriction. F-22 pilots, when told of the faulty vest, said that they hadn’t noticed it was causing a problem, Lyon said.
F-22 pilots have flown 8,000 sorties and logged 10,000 flight hours without incident since March 8, when the last unexplained case of hypoxia was reported by a pilot, Lyon said. Pilots will continue to take precautions, but changing the valve should lower the number of hypoxia incidents, he said.
“There will be physiological incidents in the future, in the F-22 and in other aircraft. That goes with the territory of high-performance fighter aircraft and fighter operations,” he said.
F-22's latest problem: can't win over cheaper rivals in close-range fights
Published: 01 August, 2012, 19:10
[ Imagen ]
F-22 Raptor (AFP Photo / USAF)
Mysteries remain as to why the US Air Force’s F-22 Raptor pilots continue to experience symptoms of oxygen deprivation in the sky, but now a new question is being asked: does history’s costliest jet compare with its half-price counterparts?
The United States has invested about $80 billion into its Raptor fleet, which, at only 187 planes, has cost the country around $420 million apiece and has become the most expensive addition ever to the Air Force’s arsenal. According to a new report published in the latest edition of Combat Aircraft Monthly, though, the state-of-the-art jet has failed missions that put it up against the Eurofighter Typhoon, a simpler aircraft utilized by German pilots that costs a comparable measly $200 million apiece.
"We expected to perform less with the Eurofighter but we didn't," German air officer Marc Grune tells the magazine. "We were evenly matched. They didn't expect us to turn so aggressively."
Although the advantageous of the Raptor jet aren’t exactly being brought into argument, the latest report suggests that in terms of close-range, one-on-one combat, the F-22 has failed to outmaneuver its German competitor. And while the long-range capabilities of the Raptor continue to be endorsed, being unable to claim victory in an up-close-and-personal fight with a plane from another fleet is an embarrassment the US Air Force doesn’t need right now.
The Air Force is standing by its multi-billion-dollar fleet, but the latest news regarding the F-22 doesn’t end there. After months of complaints from inside the military over hypoxia-like symptoms effecting Raptor pilots, the Pentagon says they believe the root of their problems isn’t in the jet itself but with the inflatable vest that pilots are required to wear. The Defense Department is now considering new equipment for its pilots that it believes will eliminate those symptoms, which have been blamed on at least one death, but not before grounding its F-22 fleet time and time again as investigators looked high and low for the culprit.
“We have looked at everything on that system [to] the nth degree, and the bottom line is that there’s no smoking gun,” Lt. Gen. Herbert Carlisle, a high-ranking Pentagon official, told the Air Force Times earlier this year.
Pentagon spokesperson George Little said last week that in regards to its fix targeting the pilot’s vests, “The Air Force is confident the root cause of the issue is the supply of oxygen delivered to pilots, not the quality of oxygen delivered to pilots.”
The Pentagon has yet to formally conclude that its adjustments will eliminate the complaints of hypoxia like conditions. Meanwhile, F-22 pilots are prohibits from flying the aircraft above 44,000 feet.
adrian_pozo escribió:Parece que no les ha gustado el pobre desempeño del F-22 contra los Typhoon alemanes, sobre todo por el problema de llevar el oxigeno hacia los pilotos, esperemos como dice el forista Anderson que el problema se resuelva a mas tardar para fines de este año.
Coloco otro articulo sobre el tema:
Vanguardia escribió:adrian_pozo escribió:Parece que no les ha gustado el pobre desempeño del F-22 contra los Typhoon alemanes, sobre todo por el problema de llevar el oxigeno hacia los pilotos, esperemos como dice el forista Anderson que el problema se resuelva a mas tardar para fines de este año.
Coloco otro articulo sobre el tema:
Lo que faltaba,alimentar mas el lobby Typhoon...
Jaldo escribió:Les dejo un buen video sobre los cazas 5ta generacion,especialmente el F-22. Miren la maniobra que hace en el minuto 2:36
http://player.vimeo.com/video/3437045?autoplay=1
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