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Moose135
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New Restrictions For F-22

Tue May 15, 2012 9:29 pm

SecDef Panetta has placed new restrictions on the F-22, and ordered the Air Force to expedite installation of an automatic backup oxygen system in the F-22

Quote:
5/15/2012 - WASHINGTON (AFNS) -- With safety remaining his top concern, Defense Secretary Leon E. Panetta has ordered the Air Force to take additional steps to mitigate risks to F-22 pilots, George Little, acting assistant secretary of defense for public affairs, said May 15 during a Pentagon news conference.

Beginning in 2008, a few pilots experienced hypoxia-like symptoms when flying the aircraft, Little said. Hypoxia is a deficiency of oxygen. There have been a total of 12 cases of these hypoxia-like symptoms affecting pilots.

Little said the secretary has followed developments in the F-22 closely and has directed the Air Force to expedite the installation of an automatic backup oxygen system in all of the planes.

In addition, effective immediately, all F-22 flights will remain near potential landing locations to enable quick recovery and landing should a pilot encounter unanticipated physiological conditions during flight, Little said.


Full story here:
http://www.af.mil/news/story.asp?id=123302134


The story doesn't specify what "remain near potential landing locations" means, but in another story, they used the term "proximate distance" of an airfield and said this order would cause F-22 air patrols over Alaska to be halted until the problem is remedied.

[Edited 2012-05-15 14:32:57]
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Dreadnought
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RE: New Restrictions For F-22

Wed May 16, 2012 12:56 am

Quoting moose135 (Thread starter):
Beginning in 2008, a few pilots experienced hypoxia-like symptoms when flying the aircraft, Little said. Hypoxia is a deficiency of oxygen. There have been a total of 12 cases of these hypoxia-like symptoms affecting pilots

I don't get it. Change out the regulator on the oxygen system, or fix some other component - they should be able to fix this in a couple of weeks throughout the fleet. This problem has been known about for some time -why does it take so long to fix?
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zanl188
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RE: New Restrictions For F-22

Wed May 16, 2012 1:22 am

Quoting Dreadnought (Reply 1):
I don't get it. Change out the regulator on the oxygen system, or fix some other component - they should be able to fix this in a couple of weeks throughout the fleet. This problem has been known about for some time -why does it take so long to fix?

Because it's an OBOGS and they don't know where the impurities are coming from. They tried adding filters but discovered carbon from the filters in the pilots lungs. For a while they thought it was because they were starting the engines in the hangar , thereby adding exhaust products to the OBOGS mix, at Elmendorf but then they saw the same problem at other bases.....
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checksixx
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RE: New Restrictions For F-22

Wed May 16, 2012 3:37 am

Quoting moose135 (Thread starter):
said this order would cause F-22 air patrols over Alaska to be halted until the problem is remedied.

Well whoever said that can't think straight...what would be the difference in a unit training over Virginia compared to Alaska.
 
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Moose135
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RE: New Restrictions For F-22

Wed May 16, 2012 3:57 am

Quoting checksixx (Reply 3):
Well whoever said that can't think straight...what would be the difference in a unit training over Virginia compared to Alaska.

That is per the DoD - they have imposed a maximum distance it can fly from an airfield, to allow the pilots to land in an emergency.

From: http://www.google.com/hostednews/ap/...d=7808fe61d5704c93a4378d93dc38b35e

Quote:
But Panetta said the plane would give up long-distance air patrol missions in Alaska until the planes have an automatic backup oxygen system installed or until Panetta agrees the F-22 can resume those flights. Other aircraft will perform those missions in the meantime.

From that AP story, the specifics of the distance limits are being left up to individual unit commanders and pilots. It's probably a relatively short distance to their training areas in Virginia, say, while a patrol over Alaska would be much longer and take them further away from base.
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Cadet985
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RE: New Restrictions For F-22

Wed May 16, 2012 5:33 am

What's the bigger blunder...the F-22 or the JSF at this point?

Marc
 
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Francoflier
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RE: New Restrictions For F-22

Wed May 16, 2012 7:43 am

Quoting Cadet985 (Reply 5):
What's the bigger blunder...the F-22 or the JSF at this point?

I doubt an O2 issue warrants calling an aircraft a blunder by any definition.
However, what is it about this oxygen delivery system that is so special that it provides so many headaches?
Fighter jets have had O2 systems for decades, why is a fix seemingly so hard to fix?

Is it that they can't find the exact source of the problem?
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trex8
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RE: New Restrictions For F-22

Wed May 16, 2012 8:59 am

Quoting francoflier (Reply 6):
Is it that they can't find the exact source of the problem?

Exactly! Can't fix a problem you can't identify accurately.
 
ebj1248650
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RE: New Restrictions For F-22

Wed May 16, 2012 4:39 pm

What advantage does the OBOGS have over the old liquid oxygen converter that makes it so important to retain? How long would it take (or have taken) to replace the system with the tried and true LOX converter?
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connies4ever
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RE: New Restrictions For F-22

Wed May 16, 2012 6:49 pm

Quoting checksixx (Reply 3):
Quoting moose135 (Thread starter):
said this order would cause F-22 air patrols over Alaska to be halted until the problem is remedied.

Well whoever said that can't think straight...what would be the difference in a unit training over Virginia compared to Alaska.

I'm thinking there are a lot more airfields at hand in Virginia than in Alaska, therefore the ability to be on the ground quickly is more likely, in case of a problem.
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NoUFO
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RE: New Restrictions For F-22

Wed May 16, 2012 6:54 pm

Quoting ebj1248650 (Reply 8):
What advantage does the OBOGS have over the old liquid oxygen converter that makes it so important to retain?

The first paragraph of the article here could provide an answer:
http://www.f20a.com/f20obogs.htm
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bennett123
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RE: New Restrictions For F-22

Wed May 16, 2012 9:36 pm

So do the F20 and AV8B already have OBOGS?.
 
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Francoflier
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RE: New Restrictions For F-22

Wed May 16, 2012 9:53 pm

Quoting NoUFO (Reply 10):

So, spend a dollar to save a dime?

Aircrafts are more and more like new automobiles... Tried and tested doesn't sell, customers want the fancy new tech.
 
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zanl188
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RE: New Restrictions For F-22

Wed May 16, 2012 10:15 pm

Quoting francoflier (Reply 12):
So, spend a dollar to save a dime?


If you can eliminate the LOX airman & his trailer you also eliminate the following:

- Onbase LOX Plant
- Deploying the LOX airman & his trailer
- Equipping airlift aircraft to transport the LOX trailer (needs to be vented)
- Retirement, disability, medical benefits for the LOX airman
- LOX airman's tech school
- Bureaucracy associated with the LOX airman. His boss, his boss's boss, awards & decs, performance reports

.. and probably some other stuff I hadn't considered. It adds up
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bennett123
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RE: New Restrictions For F-22

Wed May 16, 2012 10:21 pm

LOX is nasty stuff, and it's elimination is a bonus.

However, surely OBOGS has running costs as well.
 
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ssteve
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RE: New Restrictions For F-22

Thu May 17, 2012 5:58 am

Interesting post here:
http://www.lawyersgunsmoneyblog.com/2012/05/f-22-losses

Anyone see 60 minutes?
 
ThePointblank
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RE: New Restrictions For F-22

Thu May 17, 2012 7:30 am

Quoting francoflier (Reply 6):
I doubt an O2 issue warrants calling an aircraft a blunder by any definition.
However, what is it about this oxygen delivery system that is so special that it provides so many headaches?
Fighter jets have had O2 systems for decades, why is a fix seemingly so hard to fix?

Is it that they can't find the exact source of the problem?

The F-22 flies and cruises at a much higher altitude than any other fighter in the USAF inventory. While the exact maximum altitude a F-22 is classified, it is generally agreed upon by military analysts that the F-22 is designed to fly at altitude of over 70,000ft. Obviously, any issues with the oxygen generation or the ECS packs is greatly magnified at such higher altitudes.
 
bennett123
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RE: New Restrictions For F-22

Thu May 17, 2012 8:53 pm

What is the advantage of flying so high?.
 
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Francoflier
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RE: New Restrictions For F-22

Thu May 17, 2012 9:22 pm

Quoting ThePointblank (Reply 16):
The F-22 flies and cruises at a much higher altitude than any other fighter in the USAF inventory.

Wouldn't that make an even stronger case for the use of LOX? Scrubbing O2 from the atmosphere at these altitudes must be a real challenge.

Quoting ZANL188 (Reply 13):
you also eliminate the following:

I guess there is more to it than just a guy and a cart.
I imagine handling one of the universe's most powerful oxidizer near aircrafts gorged with fuel and explosives isn't the healthiest or most trivial operation...

Then again, is the whole affair such a burden on the overall operating budget of a large air force? Most other planes still use it so the structure will keep existing, and the next generation of fighters promises to be mostly pilotless, so it would still rise the question of overall benefits vs. cost over time, wouldn't it?

I'm also not very informed in the technical requirements of military aviation so it's a purely non-rethorical question!
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Legs
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RE: New Restrictions For F-22

Thu May 17, 2012 11:35 pm

Quoting francoflier (Reply 18):
Scrubbing O2 from the atmosphere at these altitudes

As far as the OBOGS system goes, altitude isn't a concern. OBOGS systems use bleed air from the engine, not ambient air.

Quoting francoflier (Reply 18):
explosives isn't the healthiest or most trivial operation.

It's a pretty big pain in the butt. The biggest problem is the safety rules that LOX operations impose. From memory, we had a 50m personnel exclusion zone and a 100m vehicle/ignition source exclusion zone around the aircraft during replenishment, during which only the LOX techs could be on the plane.

However, like anything else, these problems aren't insurmountable with a bit of planning and training. And OBOGS systems pose their own problems, as they need to be serviced by specialised equipment at regular intervals. Generally its a pretty easy swap though, like other LRU's
 
PlayLoud
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RE: New Restrictions For F-22

Fri May 18, 2012 4:03 am

Quoting bennett123 (Reply 17):
What is the advantage of flying so high?.

I'm no expert, but I would imagine flying higher would increase the range of your weapons.

Not only do your AA missiles start from a higher altitude, but they can pick up more speed and have less drag to slow them down due to the thinner air.
 
flyingturtle
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RE: New Restrictions For F-22

Fri May 18, 2012 7:29 am

Quoting bennett123 (Reply 17):

And don't forget the area you can cover with your radar.


David
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connies4ever
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RE: New Restrictions For F-22

Fri May 18, 2012 2:14 pm

Quoting PlayLoud (Reply 20):
Quoting bennett123 (Reply 17):
What is the advantage of flying so high?.

I'm no expert, but I would imagine flying higher would increase the range of your weapons.

Not only do your AA missiles start from a higher altitude, but they can pick up more speed and have less drag to slow them down due to the thinner air.

A problem would be though, flying at FL700 or higher, that aerodynamically the missiles would be less stable. Small aerosurfaces + very thin air means less "bite". This also applies to the aircraft itself, the ailerons/flaperons, whatever you want to call them, will have less effect at that altitude. For sure the F-22 would not be very aerobatic at this altitude. Not that it would find many aircraft at that level in the first place.

Air breathing a/c have zoom climbed to FL1000 fairly frequently, but control authority is usually marginal at best, spins being a not uncommon outcome -- this was an issue with F-104 zooms for example. NASA had a small fleet of NF-104 a/c that had thrusters to maintain attitude control at extreme altitudes. U-2s flying at 70K+ altitudes are basically cruising and not doing much else (except for all the intel being collected, of course). SR-71s, when in service, were basically creating their own local flight regime, surfing on their own pressure wave.
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bigjku
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RE: New Restrictions For F-22

Fri May 18, 2012 2:50 pm

Quoting bennett123 (Reply 17):
What is the advantage of flying so high?.

In addition to the weapons issues with AAM's mentioned above it also makes a huge difference in dealing with SAM's and the range of glide weapons like the SDB.

While many SAM's can get up to high altitude their range decreases quite a bit and your reaction time goes up a fair amount as well. A fair number of SAM systems are totally taken out of the equation at that altitude as they can't even get up there. Most SAM's that can get up there suffer reduced performance at that altitude giving the aircraft a much bigger chance of escaping. With a target that can move at a really good clip like the F-22 and that is hard to see it becomes a very very hard SAM target at that altitude, allowing it to take the Air Superiority fight to the enemy in many ways as well as using things like SDB's to gut air defense systems and fight inside of them.
 
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RE: New Restrictions For F-22

Fri May 18, 2012 4:22 pm

Quoting bennett123 (Reply 17):
What is the advantage of flying so high?.
Quoting BigJKU (Reply 23):
In addition to the weapons issues with AAM's mentioned above it also makes a huge difference in dealing with SAM's and the range of glide weapons like the SDB.

In a word, the advantage is energy. An airplane at 70,000ft has a whole lot of potential enegy it can trade for speed or range. The same goes of its weapons. Most missiles have a short enough burn stage in comparison to their range. As BidgJKU says, you are a lot harder to hit at that height than say 35,000ft. The area from which an adversary can actually get himself into a position which offers a firing solution are very limited as the missile and plane will be climbing throughout their interept course. On the other hand your weapons will have far greater range than they would at a lower altitudes.
 
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kanban
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RE: New Restrictions For F-22

Wed Jun 06, 2012 4:38 pm

Looks like they're investigating the pressure suit as a source of the problem per this article

http://www.flightglobal.com/blogs/th...400m-has-rough-time-during-la.html

sounds reasonable, won't be the first time the problem wasn't in the first system investigated.
 
connies4ever
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RE: New Restrictions For F-22

Wed Jun 06, 2012 7:08 pm

Quoting spudh (Reply 24):
Quoting bennett123 (Reply 17):
What is the advantage of flying so high?.
Quoting BigJKU (Reply 23):
In addition to the weapons issues with AAM's mentioned above it also makes a huge difference in dealing with SAM's and the range of glide weapons like the SDB.

In a word, the advantage is energy. An airplane at 70,000ft has a whole lot of potential enegy it can trade for speed or range. The same goes of its weapons. Most missiles have a short enough burn stage in comparison to their range. As BidgJKU says, you are a lot harder to hit at that height than say 35,000ft.

I certainly agree that it's much harder to hit something at FL700 than FL350. One thing would wonder about is the controllabillity of missiles at these altitudes (SDBs as well, I guess). I remember transcripts from Francis Gary Powers after he was released by the Russians indicating that missiles fired at the U-2 were tumbling when they got near his altitude, which was somewhat more than FL700. Seems to me with such a thin medium, you'd need more 'keel surface' to ensure a steady glide. But maybe that's just me.
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sweair
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RE: New Restrictions For F-22

Wed Jun 06, 2012 7:16 pm

At what flight level did the SR71 fly? Must have been up there at FL700? The coolest aircraft ever made IMO.
 
connies4ever
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RE: New Restrictions For F-22

Wed Jun 06, 2012 7:53 pm

Quoting sweair (Reply 27):
At what flight level did the SR71 fly? Must have been up there at FL700? The coolest aircraft ever made IMO.

Actually one of the hottest ! At M=3 (could actually get to about 3.3 or 3.4 depending on conditions, I believe) the wing leading edge would get pretty hot. Heat was dumped into the fuel to make it atomize better in the engine hot section. Not sure the wing would glow dull red, but I think the temp was around 600-700F.

Could cruise at around FL800 or somewhat higher, I believe. Have seen references to 'skipping' out to around 125,000 but I'm a little dubious about that. Loss of control authority could be an issue out there, you're basically in space at that point. Mostly at that altitude the SR-71, and the A-12 before it, were surfing on the pressure wave they were generating. I am not clear exactly how much aerodynamic lift the wings were actually generating. Not sure that would apply to the F-22 as it's a lot slower.

But the A-12/SR-71 were another of Kelly Johnson's triumphs. P-38 Lightning, P-80 Shooting Star, many say the Hercules (I am not certain about that), U-2, and others. There was also a very exotic a/c codenamed Suntan, to use LH2 as a fuel, fly at 100,000 ft, M=2.5 minimum.

http://en.wikipedia.org/wiki/Lockheed_CL-400_Suntan
http://www.globalsecurity.org/intell/library/reports/other/ch8-3.htm

Cancelled before flown, unfortunately. Probably at the Skunk Works there have been several of these things still-born.
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sweair
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RE: New Restrictions For F-22

Wed Jun 06, 2012 7:59 pm

I know a viggen pilot managed to lock on the SR71 once, but that took a lot of preparation and it lost its lock fast, that thing could fly   For a micro rocket it could have launched from up there? Almost up in space.. I am sure they did the numbers and all that.

There is no cheap way to launch a space craft, we have not solved the anti gravity problem yet.
 
connies4ever
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RE: New Restrictions For F-22

Wed Jun 06, 2012 8:39 pm

Quoting sweair (Reply 29):
I know a viggen pilot managed to lock on the SR71 once, but that took a lot of preparation and it lost its lock fast, that thing could fly For a micro rocket it could have launched from up there? Almost up in space.. I am sure they did the numbers and all that.

There was a variant of the SR-71 designated M-21 that carried a ramjet drone between the fins. The person occupying the back seat where the RSO would normally be controlled the drone. I believe on the 1st launch attempt, the drone hit one of the fins, damaging it, SR-71 went into a spin. Pilot managed to get out, drone operator not. I don't think this was tried again, and the drones (from Marquardt) were launched from B-52s using a rocket booster to get it up to a speed where the ramjet would work. Boundary layer flow issues and the pressure of the shock wave make launching things in supersonic flight problematic. AAMs can work since they accelerate extremely rapidly away from the launching a/c.

Note that Pegasus is an air-dropped satellite launcher. But from a subsonic a/c (actually ex-Air Canada L-1011).
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rwessel
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RE: New Restrictions For F-22

Thu Jun 07, 2012 3:28 am

Quoting connies4ever (Reply 30):
There was a variant of the SR-71 designated M-21 that carried a ramjet drone between the fins. The person occupying the back seat where the RSO would normally be controlled the drone. I believe on the 1st launch attempt, the drone hit one of the fins, damaging it, SR-71 went into a spin. Pilot managed to get out, drone operator not.

They had three successful launches of the D-21 drone from the M-21, the fourth had the collision after the engine on the drone failed to start. Both crew ejected successfully from the M-21, but the backseater drowned.
 
sweair
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RE: New Restrictions For F-22

Thu Jun 07, 2012 6:21 pm

The SR71 has no rival since its days, it is truly a marvel of technological use back in the days it was developed. Very impressive work from LM. The F35 puts their history to shame.
 
bigjku
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RE: New Restrictions For F-22

Thu Jun 07, 2012 6:47 pm

Quoting spudh (Reply 24):
In a word, the advantage is energy. An airplane at 70,000ft has a whole lot of potential enegy it can trade for speed or range. The same goes of its weapons. Most missiles have a short enough burn stage in comparison to their range. As BidgJKU says, you are a lot harder to hit at that height than say 35,000ft. The area from which an adversary can actually get himself into a position which offers a firing solution are very limited as the missile and plane will be climbing throughout their interept course. On the other hand your weapons will have far greater range than they would at a lower altitudes.

Yeah, I always felt people got the wrong impression of altitude from the U-2 incidents and the cancellation of the B-70. Targets up there are very hard to hit and taking down that U-2 took a lot of custom work by the USSR. Plus the thing is basically a powered glider.

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