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29 juillet 2011 5 29 /07 /juillet /2011 17:15



July 29th, 2011 By POGO – DEFENCE TALK


First it was oxygen problems. Then there was treatment for "physiological symptoms." And now the news is that toxins are keeping the F-22s down.


But that doesn't mean we have definitive answers yet. Toxins in the cockpit? Yes. Where are they coming from? There is still debate over that.


According to the Air Force Times, blood tests of F-22 pilots showed a host of chemicals, including anti-freeze, propane and burned polyalphaolefin, a synthetic oil, after flights where they reported experiencing cognitive problems.


These toxins, along with carbon monoxide, may be causing hypoxia, which is a lack of oxygen. Hypoxia can cause reduced brain function and memory loss. F-22 pilots reported being unable to remember how to change radio frequencies and scraping treetops when approaching the runway.


In November 2010, an F-22 crashed in Alaska and the pilot, Capt. Jeffrey Haney, was killed. Sources told the Air Force Times that in his final radio calls he sounded drunk, a symptom of hypoxia.


Back in May, we wrote about the grounding of the F-22 fleet and asked why these widespread problems were not detected in testing. It may be that the problem is still with the On-BoardOxygen Generating System (OBOGS), but the source of the toxins is unclear.


As one POGO commenter recently mentioned, one possibility is that what’s happening here “isn’t too different from running your car engine while the garage door is closed.”


From the Air Force Times:

“Part of the problem, at least for pilots flying from Joint Base Elmendorf-Richardson, Alaska, where many of the known incidents have occurred, may be the startup procedures used in winter, one source said.


“Because of the harsh climate, pilots often start their jet engines inside a hangar before taking off. That could allow exhaust gases to be trapped in the building, sucked back into the engines, and ingested into the bleed air intakes that are located within the engines’ compressor sections that supply the OBOGS, sources said.


“On the other hand, a different source told the Air Force Times that “many of the hypoxia incidents have occurred well into flights or even during a day’s second mission, long after the plane has left the Elmendorf hangar.”


“Either way, considering that, on average, one F-22 costs $350 million and each hour of flight costs $44,000, ensuring that they can fly is both a safety and a budgetary concern.


The F-22 fleet was grounded 86 days ago. If the oxygen problems are not solved in the next 124 days, all F-22 pilots will have to be re-qualified. That process could take four to six weeks, according to the Air Force Times. And since all of the pilots would need to be re-qualified, non-current pilots would be qualifying each other, which would add to the delays.


If that happens, the F-22s and their pilots might not be ready to fly until January 2012.


For now, pilots are putting in more time at the gym, practicing in simulators, and taxiing to the end of the runway and then returning to the hangar.


But the questions POGO's Director of Investigations Nick Schwellenbach had about the program two weeks ago are still unanswered.


What did the Air Force know before the recent groundings? As Bloomberg noted, there were nine instances from June 2008 and February of this year that triggered an earlier safety investigation into the Honeywell oxygen system. Then five more since February leading to the latest investigation and groundings.


Plus, there is the possibility that the November 2010 crash and death were related to the oxygen system, although we do not know if the accident investigation is pointing that way or not yet.


Were there inklings of oxygen system problems before June 2008? What did the earlier oxygen safety investigation find? Why are problems in this critical life support system only now coming to light?

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