Forum: General F-35 Forum

The prolonged grounding of the [Link pending approval] Air Force's F-22 Raptor fleet may be due to carbon monoxide entering the cockpit via the aircraft's oxygen system, two sources said.

Service leaders grounded the stealthy twin-engine fighter May 3, after 14 incidents when F-22 pilots suffered "hypoxia-like [Link pending approval];

Air Force officials initially suspected a problem with the aircraft's On-Board Oxygen Generation System (OBOGS), but that is looking less likely, the sources said.
Instead, investigators now suspect that carbon monoxide generated by the plane's jet engines is getting into the cockpit.

Part of the problem may be the procedures used at Elmendorf Air Force Base, Alaska, where most of the known incidents have occurred. Because of the harsh climate, pilots often start their jet engines inside a hangar before taking off. Investigators suspect that exhaust gases are getting trapped in the building and subsequently sucked back into the engines, where they enter the bleed air intakes that supply the OBOGS, sources said.
The design and placement of the intakes, which are located within the engines' compressor sections, are fairly standard for jet aircraft.
There is no immediate fix in sight, sources said.
Asked for comment, an Air Force spokesman said he had no further information at this time.
"The safety of our aircrews is paramount, and the Air Force continues to carefully study all factors of F-22 flight safety," said Maj. Chad Steffey.

However, a July 21 press release says Air Force Secretary Michael Donley has ordered the service's Scientific Advisory Board to conduct a "quick-look study" of "aircraft using on-board oxygen generation [Link pending approval];

One aviation safety expert said that if the hypoxia is being caused by carbon monoxide in the cockpit, the gas is likely being generated by the plane's engines.
"I would think that it has something to do with exhaust flow somehow getting into the oxygen generating system," said Hans Weber, who sat on the [Link pending approval] Federal Aviation Administration's Research, Engineering and Development Advisory Committee, and is president of Tecop International, a San Diego consulting firm.
Even a small amount of the colorless, odorless gas can have serious effects, Weber said.
"It doesn't take a large concentration of carbon monoxide to start affecting people, making them ill - and not just ill but really diminishing their ability to perceive [Link pending approval];
Weber said the difficulty of the fix will depend on the problem.
If the carbon monoxide is being ingested because the engines are being started in confined spaces, a fix could be as simple as moving the jet outside, Weber said. If the engine must be started inside the hangar, the startup of the oxygen system might be delayed until the jet is out in the open, he said.
But if dangerous levels of carbon monoxide are entering the cockpit despite these changes, the Air Force might have to add bulky cartridges or scrubbers to the life-support system, he said.
The [Link pending approval] Navy has had similar problems with the OBOGS on its F/A-18 Hornet, which sucked carbon monoxide into its oxygen system during carrier operations.
Between 2002 and 2009, Hornet aviators suffered 64 reported episodes of hypoxia, including two that killed the pilots, according to the July-August 2010 issue of "Approach," a Navy Safety Center publication.

Some 77 percent of the incidents happened in single-seat Hornets, which saw [Link pending approval] incidents per 100,000 flight hours. The two-seat version saw [Link pending approval] incidents per 100,000 flight hours.

According to Navy documents, "Prolonged exposure to jet engine exhaust while sitting behind another aircraft waiting to take off and operating with low bleed air pressures can result in carbon monoxide (CO) breaking through … into the pilot's breathing [Link pending approval];

The Navy modified the planes' OBOGS to fix the problem, has had no recent similar incidents, and is not currently investigating the systems, Naval Air Systems Command officials said.

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Nice informative post rontako thanks! Thumb

One minor quibble, can we have a link back to the source please?

Lockheed Martin: F-22 And F-35 Oxygen Systems 'Very Different' (DEFENSE DAILY 08 MAY 12) ... Mike McCarthy

http://www.hrana.org/news.asp#LockheedMartin

"The oxygen generating systems for pilots aboard the F-22 and F-35 are "very different," but Lockheed Martin evaluates the lessons learned on the F-22 to ensure problems do not arise on its latest fighter jet, the company said yesterday....

..."The F-35 program continuously monitors issues present in other aircraft assessing applicability to our current design," Laurie Quincy, a Lockheed Martin spokeswoman said. "The F-35 and F-22 have common aircraft and oxygen system suppliers; but the systems are very different.”

"The program has leveraged the lessons learned from F-22 development to enhance the F-35 across all subsystems, including the Onboard Oxygen Generating System (OBOGS)," she added. Lockheed Martin was not more specific about differences and similarities between the two systems and referred additional questions on the F-35 to the Pentagon. The F-35 Joint Strike Fighter program office did not return a phone inquiry...."

Canadian Journalists/Reporters are extra special. Very Happy

See story above... Compare and Contrast... WHICH PILOT? Rolling Eyes

Pilots worry about F-35 oxygen system Jean Peladeau, QMI Agency May 11, 2012

http://www.wellandtribune.ca/2012/05/11 ... gen-system

"OTTAWA - U.S. fighter pilots are complaining that the same breathing apparatus systems expected to be used in the F-35 fighter jets Canada plans to buy are faulty and fail to deliver enough oxygen to pilots in certain flying situations....

...Lockheed Martin, which makes the F-22 as well as the F-35, plans to use the same oxygen system in both planes....

...Chris McCluskey, a spokesman for associate defence minister Julian Fantino said "questions concerning [the F-35] progress should be directed to the manufacturer."

Alison Orne, a spokesman for Lockheed Martin, based in Marietta, Ga., told QMI: "I have to refer you to your respective government for comments."

While Lockheed and the government play pass the buck, Honeywell is showcasing the F-35 as a new platform for its product in the 2012 catalog of "life support systems."

Go to the URL to see F-22 pilots are complaining about F-22 OBOGS. Evil or Very Mad

spazsinbad wrote:

Canadian Journalists/Reporters are extra special. Very Happy

See story above... Compare and Contrast... WHICH PILOT? Rolling Eyes

Pilots worry about F-35 oxygen system Jean Peladeau, QMI Agency May 11, 2012

http://www.wellandtribune.ca/2012/05/11 ... gen-system

"OTTAWA - U.S. fighter pilots are complaining that the same breathing apparatus systems expected to be used in the F-35 fighter jets Canada plans to buy are faulty and fail to deliver enough oxygen to pilots in certain flying situations....

...Lockheed Martin, which makes the F-22 as well as the F-35, plans to use the same oxygen system in both planes....
9 www
...Chris McCluskey, a spokesman for associate defence minister Julian Fantino said "questions concerning [the F-35] progress should be directed to the manufacturer."

Alison Orne, a spokesman for Lockheed Martin, based in Marietta, Ga., told QMI: "I have to refer you to your respective government for comments."

While Lockheed and the government play pass the buck, Honeywell is showcasing the F-35 as a new platform for its product in the 2012 catalog of "life support systems."

Go to the URL to see F-22 pilots are complaining about F-22 OBOGS. Evil or Very Mad

A little research would have revealed that the OBOGS are different for both jets. The Canadian,report seems intended to tar the F-35 by lumping it in with,the F-22's ongoing troubles.. guilt by association.

Lockheed: F-35 Oxygen System 'Very Different' Than Troubled Sibling
May 25, 2012 by John T. Bennett

http://www.usnews.com/news/blogs/dotmil ... ed-sibling

"The fighter jet fleet in which the Pentagon has staked its future is equipped with a "very different" oxygen system than the one that has plagued the F-22, its Lockheed Martin sibling....

...Lockheed Martin responded to DOTMIL after multiple requests for comment, sounding a confident tone.

"They are different systems," Lockheed spokesman Michael Rein says. "The F-35 and F-22 have common aircraft oxygen system suppliers but the systems are very different...The two systems each utilize a similar approach and architecture, but they are packaged and implemented differently.

"The F-35 program continuously monitors issues present in other aircraft assessing applicability to our current design," Rein says. "The program has leveraged the lessons learned from F-22 development to enhance the F-35 across all subsystems, including the Onboard Oxygen Generating System."..."

Forum: General F-35 Forum

OBOGS Suspects After F-22 Grounding