F-22 Problems Continue

[Pielstick]

Interview with two F-22 pilots about the continuing mysterious hypoxia problem:
http://www.cbsnews.com/video/watch/?...g;mostpopvideo


NYT article reporting some pilots have asked not to fly the aircraft and be re-assigned:
http://www.nytimes.com/aponline/2012...m.html?_r=2&hp


If I were a US taxpayer I'd be asking some pretty serious questions. Hopefully they find the cause of the problem before a pilot is killed. Smacks a lot of Britain in the 1950s when commercial and political interests put new aircraft with outstanding defects into squadron service and pilots were expected to take their chances.

[Vanoi]

Have they still not fixed the oxygen supply problems to the pilot? This is why pilots refuse to fly the F-22.

[Pielstick]

Nope they never identified the cause. It went back into service with a slightly modified system that had a charcoal filter designed to catch any contaminants. They then found the charcoal was contaminating the air the pilots were breathing....

They're also flying with little oxypulse meters which they're supposed to monitor - exactly the same thing that some general aviation pilots fly with.

There was a theory early on that the problem was procedural. The early hypoxia incidents were all at Elmendorf AFB in Alaksa, where it was standard procedure to start the aircraft's engines whilst it was still in the hangar. The theory was exhaust gases were being re-ingested and finding their way into the pilot's oxygen supply. I think this theory has been scuppered though by hypoxia incidents from aircraft based at Langley AFB in Virginia - where the two pilots in the video interview above are based.

It's still pretty shocking that 18% of F-22 pilots have experienced these symptoms.

[mrmouth]

It's still pretty shocking that 18% of F-22 pilots have experienced these symptoms.

Those numbers make it sound a lot worse considering the number of pilots. It's just 14 incidents. Once every 10,000 sorties.

Overall, air supply issues in new jets are common. Almost every new design has had these issues. The F-18 had 64 incidents in 7 years.

[GreyFox]

Those numbers make it sound a lot worse considering the number of pilots. It's just 14 incidents. Once every 10,000 sorties.

Overall, air supply issues in new jets are common. Almost every new design has had these issues. The F-18 had 64 incidents in 7 years.

Tell me, which would cause more concern - 14 incidents out of a fleet of 190 aircraft, or 64 out of a fleet of 1500 (or 2000 if you include the Super Hornet)?

[Town Watch]

Tell me, which would cause more concern - 14 incidents out of a fleet of 190 aircraft, or 64 out of a fleet of 1500 (or 2000 if you include the Super Hornet)?

well, percentigewise, 14 out of 190 is a lot worse failure rate, than 64 out of 1500, 7,368 percent vs 4,267 percent

In any case, truthfully, it also matter what kind problems you got in the aircraft, or whether it's indeed pilot error. They are not after all some kind of perpetual motion machines with eternal guarantees even though reliability is a sought after feature in most weapons sytems. So the duration of the airframe and parts are limited, at least some of those F-15s and F-16s failures had these problem I think.

On the other hand if the source of the problem is design related, then something went wrong already in the engineering. Not surprising, given how much attention to detail must be maintained in the other critical design features. Admittedly there may have been similar problems with the design of F-15 and F-16 when they were built.

[Adar]

It's not a bug, it's a feature imported from the highly successful MDK computer game.

Spoiler Alert, click show to read: 

Where the main characters Sniper rifle slowly suffocates him by blocking his air supply when used.

[Pielstick]

Also forgot to say kudos to these two pilots for putting their careers in jeopardy to highlight the issue.

[Exarch]

boy are their superiors going to be pissed for breaking ranks and going to the press; i foresee many hours of cleaning the floors with toothbrushes and breaking big rocks into little rocks for these two pilots.

[Town Watch]

Defective weapons in peacetime, will cost lives in war time?

A little reminiscent of how the Americans protected the veil of secrecy of their WW2 torpedoes to the extent that they didn't even field test them in realistic or feasible war conditions. Also depression era cuts influenced lack of testing but the secrecy issue played it's part too.

Didn't help them a whole after Pearl Harbor, they had the torpedo crisis for an entire year in wartime.

[mrmouth]

It was the Super Hornet program, so I should have eluded to that. So 64 over 7 (2001-2009) years since the SH was introduced, and they apparently solved the problem.

And it is more the flight hours/sorties per incident that we need to be looking at.

These new blended O2 systems are still relatively new. It used to be just compressed O2, but now use OBOGS (Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System) initially developed by NASA, that now most all countries use. All countries have had these issues, but they are not publicized like this.

[Adar]

These new blended O2 systems are still relatively new. It used to be just compressed O2, but now use OBOGS (Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System) initially developed by NASA, that now most all countries use. All countries have had these issues, but they are not publicized like this.

That is because the other countries solved the issues during the testing phase.

In Gripen the only known issue related to when the OBOGS was added to the C/D variant was pressure problems in the anti-g system that had also been redesigned. This caused one (or a few, I cannot prove a negative ) grey out incidents related to a component not delivering enough pressure to support the anti-G system at high G-levels.

[mrmouth]

In Gripen the only known issue related to when the OBOGS was added to the C/D variant was pressure problems in the anti-g system that had also been redesigned. This caused one (or a few, I cannot prove a negative ) grey out incidents related to a component not delivering enough pressure to support the anti-G system at high G-levels.

Which is the likely cause in the F-22. You are dealing with significant more g forces due to higher maneuverability. Not to mention unique maneuvers.

Most everything was deigned from scratch, or heavily redesigned to save weight. The OBOGS design in the F-22 is totally unique. They use the same system in the F-35, but it is the stock Honeywell.

[Adar]

Edit: Another story regarding the oxygen issues. This time a pilot was forced to pull out during a Red flag exercise.

Which is the likely cause in the F-22. You are dealing with significant more g forces due to higher maneuverability. Not to mention unique maneuvers.

On Wikipedia it's attributed a design load of +9/-3 which is the same as any modern fighter. And it's unique capabilities (high speed, high service ceiling and stealth) means that a F-22 pilot maneuvering like a Eurofighter pilot is either doing something stupid or have gotten into serious trouble.

Most everything was deigned from scratch, or heavily redesigned to save weight. The OBOGS design in the F-22 is totally unique. They use the same system in the F-35, but it is the stock Honeywell.

Being unique isn't really a selling point when it is suffocating the pilots. I also had a look at the Honeywell web page and the Gripen/BAE system looked more different than the F-22/F-35 OBOGs. But that doesn't really matter, my only point is that no other aircraft have been plagued by these issues in the way the F-22 has like you claimed.

the reporter implies faulty oxygen filtering is the problem, so what happens if that proves not to be the case?

Either they fix it, provide a work around or another F-22 pilot get killed.

[Pielstick]

All countries have had these issues, but they are not publicized like this.

A few points...

As Adar pointed out, the F-22 doesn't pull more G than other fighters, the F-16 has been pulling the same G-loads for 30 years, and the Typhoon and Rafale achieve very similar G-loads. In fact, I've read several accounts which claim the Mirage 2000 is capable of pulling 12G in an instantaneous turn.

It's normal for fighters to have outstanding issues or defects early on in their careers. However, for a fighter to have a potentially fatal defect seven years after entering service is quite unusual. When we then consider the years of superlatives attributed to this aircraft in order to justify its massive price tag it must be both hugely frustrating and very embarrassing for the USAF.

After having restrictions placed on maximum altitude, then grounding, and currently restrictions on how far the thing can fly from an available runway I have to admit to experiencing a little bit of schadenfreude when I remember how F-22 cheerleaders have spent so many years telling us the F-22 is the final word and rubbishing every other fighter in the sky. However, the reality is if these problems are not solved soon a pilot will die. I would hope the life of a USAF pilot is worth more than the political and commercial interests invested in the F-22.

[Sanguinary Guardian]

Don't you Just love the F-22?

[Exarch]

the reporter implies faulty oxygen filtering is the problem, so what happens if that proves not to be the case?

[Condottiere 40K]

Pilotless aircraft, one way or another.

[mrmouth]

And I think that post highlights the absurd nature of the debate. A lot of the debate being taken up people who clearly just want to gloat. They are not taxpayers and they really dont give a . The top aerospace designers in the world have all been investigating this problem for years. There are things this jet does that push the limits of that science. A lot are still classified.

As for reported g forces, I was specifically responding to the comparison of the Gripen.

Suggesting that anyone knows the absolute max g force that an F-22 can pull in a high speed, high altitude turn, is simply wrong. We have heard everything up to 22g. They reported at an air show - 9.5g. They also have the ceiling at 50,000ft when it can probably do a lot it was designed to do upwards of 70,000ft. Point is, this isn't an aircraft that is being sold. All of the question marks were left that way for a reason, and we are filling in the blanks through accounts from people who say they know. When or if a country is allowed to buy the F-22 (minus the crazy avionics), we simply will not know. And even then it isn't likely.

Thrust vectoring greatly decreases turn radius, with a high turn rate - but you still pull max g at some point during a high speed turn. Again - the question is what max g is on this jet, and if the OBOGS system that was scaled down and lightened from the stock Honeywell, is able to delver enough air.

Being unique isn't really a selling point when it is suffocating the pilots. I also had a look at the Honeywell web page and the Gripen/BAE system looked more different than the F-22/F-35 OBOGs. But that doesn't really matter, my only point is that no other aircraft have been plagued by these issues in the way the F-22 has like you claimed.

Totally misunderstanding my use of the word unique. They scaled the thing down and lightened it. It isn't stock, and they are having problems with it in a jet that does things that have not been done before.

[Pielstick]

The most expensive, advanced and supposedly world beating fighter aircraft in aviation history has a rather serious problem where it is apparently poisoning its pilots. Is it embarrassing for the USAF? Of course. Is it embarrassing for the legion of F-22 cheerleaders who want to try and deny there's a problem? Absolutely.

Is it absurd for the pilots who are expected to fly this aircraft? Most definitely not. It's a matter of life and death.