Lockheed Martin F-22 Raptor

[Gridlock]

Where do I get a text book for this course

http://en.wikipedia.org/wiki/Chengdu_Aircraft_Industry_Group

 

[flateric]

http://www.vandenberg.af.mil/news/story.asp?id=123283235

Wolf: What can you say to the rumors that Santa is looking to use the F-22 as his new sleigh or using one to pull his sleigh?

Scott: This is a complete rumor; even though the F-22 is one the most powerful and fastest fighters in the world and could do the job of pulling Santa's sleigh very well, it is no comparison for a team of reindeer!

See, in the F-22 you have about 68,000 pounds of thrust in full afterburner. That pales in comparison to the thrust of a single reindeer and Santa has a team of nine reindeer!
Additionally, the F-22 does not have the appropriate lighting of at least a 1.21-
Gigawatt-powered red light in the nose.

Wolf: Have you and Santa talked about how much faster it would be to use a Raptor rather than reindeer?

Scott: We did discuss using a team of F-22's to pull the sleigh, but Santa decided he would stick to the tried and true power and speed of the reindeer.

Wolf: An F-22 is equivalent to how much of Santa's reindeer power?

Scott: Reindeer power is about a zillion more times powerful than the F-22's engines.
Wolf: Why would Santa look at using a Raptor to make his runs?

Scott: The 3rd Wing's F-22's are on standby in the event Santa needs some help delivering toys to the kids.

Wolf: Where would Santa put the presents if he used the Raptor?

Scott: We would put them on Bomb Release Units in the internal and side weapons bays if required.

Wolf: Would Santa need in- flight refueling or would the same thing happen to the F-22 that makes the reindeer fly?

Scott: The F-22's would require in-flight refueling to get around the world to support Santa. That's why the reindeer are so much more efficient as they only require some oats and hay that can be carried on board the sleigh.

Wolf: How do you think Santa's image would change if kids saw him flying an F-22 instead of a sleigh?

Scott: I think Santa has a great image of doing great things for the kids and community, so no matter what he arrives in; it's always Christmas when he arrives!

As kids eagerly awaited to tell Santa what they wanted for Christmas, I spoke to two sisters about Santa's arrival in an F-22.

Wolf: What did you think of Santa's new sleigh that you saw him arrive in?

Kynzee Coarsey: It was really cool and I would like to see Santa fly around in it more.

Kylee Coarsey: It was cool but it was a lot different and I like the sleigh and the reindeer better.

Wolf: How many reindeer do you think it would take to make an F-22 fly?

Kynzee: 10.

Kylee: 100.
"We think it's important at the 90th Fighter Squadron to have a Dicemen family identity and this is just part of it," said Air Force Lt. Col. Joseph Kunkel, 90th FS commander.
"We try to do things to get the families together at least once a month and we thought it would be a great idea to have Santa come down here and give gifts to the boys and girls," he said.

 

[Ogami musashi]

Doh, 68000? wasn't it supposed to be 70 000 at least?

 

[sferrin]

Doh, 68000? wasn't it supposed to be 70 000 at least?

You're asking for accuracy in an article about Santa? :

 

[Stargazer]

...

 

[Ogami musashi]

OH my bad! How is it i dared to ask a question on this forum?!! OH MY BAD! i forgot i'm on secret projects forums! Only people that know the answer can ask for questions; all the other are either:
1/stupid people
2/trolls
3/both






Excuse me sir, i was stupid enough to challenge the masters of the forum! i'm ashamed ...really.

 

[lancer21]

68,000 huh ? I knew it, it's the same story like with F-100 PW-100 -"25,000lb class" but in reality it actually developed just under 24, 000. I always knew it .

(Boy the 37,000-39,000 lb crowd is gonna go mental if you tell'em it's only 34,000lb AB thrust for F-119. Oh btw, imho , you know why i don't believe those 37-39K are real ? Because if those are the real figures , and whoever claims these figures also claims to been told by " peoples in the know" , then not only the peoples in the know , but probably themselves too would have rotten somewhere in a basement courtesy of CIA, and not allowed to bragg about in on the www.. Someday hopefully it will be disclosed and we'll see who's gonna have the last laugh . ;D )

 

[sferrin]

68,000 huh ? I knew it, it's the same story like with F-100 PW-100 -"25,000lb class" but in reality it actually developed just under 24, 000. I always knew it .

(Boy the 37,000-39,000 lb crowd is gonna go mental if you tell'em it's only 34,000lb AB thrust for F-119. Oh btw, imho , you know why i don't believe those 37-39K are real ? Because if those are the real figures , and whoever claims these figures also claims to been told by " peoples in the know" , then not only the peoples in the know , but probably themselves too would have rotten somewhere in a basement courtesy of CIA, and not allowed to bragg about in on the www.. Someday hopefully it will be disclosed and we'll see who's gonna have the last laugh . ;D )

It's difficult to argue with the sheer genius of your post but let's just do a little math.

With 275lb/sec airflow the F100-232 is able to generate 32,000lbs of thrust. That's 116.4 lbs of thrust per pound of airflow per second. Now consider the airflow of the F119 is 335lbs/sec. Do the math and you get 39,000lbs of thrust, even if the F119 is no more efficient than the -232. Given that 1. the F119 is almost certainly more efficient and 2. the -232 actually hit 37,000lbs thrust in bench tests and well, I think if you have any intelligence at all, it will be your head that explodes.

 

[lancer21]

Ah good old Sferrin, civilized and subtle like a horse in a Chinashop (or whatever the saying is). I will not contradict your maths sir , wanted to rant something about flat nozzles etc, but in fairness i do not have enough knowledge on these matters so pass.

Hopefully we'll live to see (or at least someone will ) a dash-1 or whatever it's called , or an even better idea, just ask the Chinese or Russians. They should know ;D

 

[sferrin]

Ah good old Sferrin, civilized and subtle like a horse in a Chinashop (or whatever the saying is). I will not contradict your maths sir , wanted to rant something about flat nozzles etc, but in fairness i do not have enough knowledge on these matters so pass.

What? I thought you were the expert babbling on about making people "go mental"?

 

[Triton]

Raptor 195, the final F-22, has rolled off the line at Lockheed Martin's Marietta, Ga., assembly facility.

Source:
http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3a5f1682d2-9610-4f89-bd86-e3190c321d58&plckScript=blogScript&plckElementId=blogDest

http://www.codeonemagazine.com/news_item.html?item_id=526

http://www.flickr.com/photos/lockheedmartin/6507232253/

 

[Triton]

http://www.youtube.com/watch?v=fYEx9BiJNfE

 

[Machdiamond]

Videos like these that show the faces behind all the blood, sweat and tears are so rare. Truly fantastic. Thanks for sharing.
--Luc

 

[Talon_38C]

FlightGlobal reports today that the Air Force blames the pilot was for the crash of the F-22 in Alaska last November. The blame however seems to be a bit misguided to me.

----

The F-22's oxygen supply was automatically cut off after onboard computers detected bleed air was leaking out of the engine bay, which could cause a fire, the report says. The USAF investigators were unable to determine the cause of the bleed air leak.

Shutting down the bleed air system caused the OBOGS to fail, the report says. The OBOGS filters the bleed air through a molecular sieve and delivers the oxygen to the pilot's oxygen mask.

The report concluded that Haney (the pilot) inadvertently pointed the aircraft at the ground while trying to activate the EOS, a procedure that calls on the pilot to pull up on a small ring tucked into the side of his ejection seat.
----

So the onboard computers are sophisticated enough to cut off the bleed air system and thus to the pilots oxygen mask to prevent the aircraft from catching on fire and subsequently crashing but it's not sophisticated enough to activate the EOS automatically for the pilot to keep him from crashing?

It seems to me any system that might disable oxygen to the pilot for any reason would also automatically provide some emergency remediation.

 

[flateric]

http://usaf.aib.law.af.mil/ExecSum2011/F-22A_AK_ExecSum_16%20Nov%2010.pdf
http://usaf.aib.law.af.mil/ExecSum2011/F-22A_AK_16%20Nov%2010.pdf

 

[bobbymike]

Rhetorical question of the year - Why aren't we building 500 of these now that would be a stimulus plan

 

[Talon_38C]

An interesting but rather wishy-washy report. The report really seems to make the case that the pilot is in a no-win situation stating that the "failure of an individual to absorb the material...does not indicate a training problem" and describing how difficult it might be to manually switch on the EOS under "real world physiological duress."

The sad thing is that the report fails to take the opportunity to address this issue in 'Additional Areas of Concern" section.

Once the flight computers that have after already cut off air bleed to protect the plane and thus subsequently depriving oxygen to the pilot (i.e. real world physiological duress) it stands to reason the same system be designed to safeguard the pilot and automatically switch on the EOS.

 

[sublight]

This is what it looks like when a pilot is trying to stick a glove into the seat crack to activate the emergency oxygen supply. What could possibly go wrong?

 

[Triton]

An interesting but rather wishy-washy report. The report really seems to make the case that the pilot is in a no-win situation stating that the "failure of an individual to absorb the material...does not indicate a training problem" and describing how difficult it might be to manually switch on the EOS under "real world physiological duress."

The sad thing is that the report fails to take the opportunity to address this issue in 'Additional Areas of Concern" section.

Once the flight computers that have after already cut off air bleed to protect the plane and thus subsequently depriving oxygen to the pilot (i.e. real world physiological duress) it stands to reason the same system be designed to safeguard the pilot and automatically switch on the EOS.

Indeed. It's very sad that the United States Air Force is blaming Capt. Jeff Haney for the crash because his "attention was too channelized" because he was suffocating.

 

[Triton]

This is what it looks like when a pilot is trying to stick a glove into the seat crack to activate the emergency oxygen supply. What could possibly go wrong?

Ridiculous.

 

[Matej]

There is still a chance you will enlarge your list.

http://wareye.com/german-media-said-the-united-states-should-restart-the-f-22-production-line-to-deal-with-china-j-20

 

[TomS]

Why would an editorial in German magazine have any impact on US budgetary processes? I could point to any number of similar editorials to the same effect in US publications that had no impact either.

 

[F-14D]

Why would an editorial in German magazine have any impact on US budgetary processes? I could point to any number of similar editorials to the same effect in US publications that had no impact either.

It's beyond budgetary. People in DC staked their reputation and prestige on there being no need for the F-22, and so reversing that decision, especially at the great cost it would take, would mean admitting they were "wrong". That simply does not happen.

As someone once said about the Washington mindset (but applies to other gov'ts as well) , "It is much more important not to be wrong than it is to be right".

 

[sferrin]

Why would an editorial in German magazine have any impact on US budgetary processes? I could point to any number of similar editorials to the same effect in US publications that had no impact either.

It's beyond budgetary. People in DC staked their reputation and prestige on there being no need for the F-22, and so reversing that decision, especially at the great cost it would take, would mean admitting they were "wrong". That simply does not happen.

As someone once said about the Washington mindset (but applies to other gov'ts as well) , "It is much more important not to be wrong than it is to be right".

Which is why the F-35 is called the F-35.

 

[F-14D]

Why would an editorial in German magazine have any impact on US budgetary processes? I could point to any number of similar editorials to the same effect in US publications that had no impact either.

It's beyond budgetary. People in DC staked their reputation and prestige on there being no need for the F-22, and so reversing that decision, especially at the great cost it would take, would mean admitting they were "wrong". That simply does not happen.

As someone once said about the Washington mindset (but applies to other gov'ts as well) , "It is much more important not to be wrong than it is to be right".

Which is why the F-35 is called the F-35.

Q.E.D.

 

[Sundog]

I wouldn't restart the F-22 line until we complete the ones we've already built. Maybe then they should build a stretched version that can really supercruise, to get the fuel fraction up.

It will be interesting to see what the J-20's fuel fraction is, but I wouldn't be surprised if it's a round .3, based on it's size and optimization for supercruising.

 

[flanker]

Last F-22 is already produced. The only thing they are producing now is some spares, like 4 extra sets with wings.

 

[Sundog]

Last F-22 is already produced. The only thing they are producing now is some spares, like 4 extra sets with wings.

I was referring to the reports that around 40% of them aren't really capable of going into combat, since they lack the proper systems to do so. Once again, like the F-35, they were put into production before being ready and now have to be rebuilt to have the systems added to make them effective. The purpose of concurrent engineering is to build enough of them before it's too late to cancel them.

 

[unclejim]

Exactly my concern. F-22, now F-35 is this concurrent engineering worth it?

 

[flanker]

I was referring to the reports that around 40% of them aren't really capable of going into combat, since they lack the proper systems to do so. Once again, like the F-35, they were put into production before being ready and now have to be rebuilt to have the systems added to make them effective. The purpose of concurrent engineering is to build enough of them before it's too late to cancel them.

Sounds like you are mixing numbers. 60 % is what the rate of combat readiness is for F-22. Meaning out of 10 planes, 6 can fly on a relatively short warning.

 

[Arjen]

I was referring to the reports that around 40% of them aren't really capable of going into combat, since they lack the proper systems to do so. Once again, like the F-35, they were put into production before being ready and now have to be rebuilt to have the systems added to make them effective. The purpose of concurrent engineering is to build enough of them before it's too late to cancel them.

Sounds like you are mixing numbers. 60 % is what the rate of combat readiness is for F-22. Meaning out of 10 planes, 6 can fly on a relatively short warning.

Sundog may be referring to the various F-22 blocks and their capabilities. I found this at Defense Industry Daily

Even though the F-22 is going out of production, the program itself will continue to attract spending on maintenance, spares, and upgrades. Right now the Air Force operates mostly Block-10 and Block-20 aircraft. The Block 10s are used for training at Tyndall AFB. The Block 20s use “Increment 2” hardware and software, which lets them launch JDAM bombs, and improves performance with the AIM-120C AMRAAM.
Under the Common Configuration program, the F-22A Block 10s will be upgraded to Block 20 status, but retain the original core processor. They’ll have operational capabilities, but present plans call for them to be used mostly for training. The Block 20 jets will get upgrades to the F-22A Block 30 configuration, and can then receive additional Increment 3 upgrades.
By 2016, the Air Force should have 34 Block-20 Raptors, 63 F-22A Block-30s, and 87 F-22A Block-35 aircraft. Only the Block 35 jets will be capable of using Increment 3.2 capabilities, unless the F-22’s avionics receive an open architecture makeover that brings down upgrade costs.
Increment 3.1 was set to begin OpEval in January 2011. It includes ground-looking synthetic aperture radar (SAR) modes, some electronic attack capability, geo-location of detected electro-magnetic emitters, and initial integration with the GPS-guided GBU-39 Small-Diameter Bomb (SDB-I). That last change expands the F-22’s ground attack arsenal from 1 JDAM per bay to 4 SDB-Is. The catch is that a pilot will only be able to release 2 weapons at a time.
Increment 3.2 will be a software-focused upgrade, and was expected to begin in 2014. It will provide compatibility with new AIM-9X Sidewinder short range air-air missiles, and the AIM-120D medium range air-air missile whose range, 2-way datalink, and AESA friendly features appear to be tailor-made for the F-22. MADL datalink upgrades would let the F-22 work better with other platforms, while improved emitter geo-location, improved targeting capabilities, better jamming resistance, Link-16 track fusion, and Automatic Ground-Collision Avoidance System (AGCAS) round out the electronics upgrade highlights. Under 3.2, pilots will be able to release all 8 SDB-Is at once, and the jets will receive full compatibility with the advanced AIM-120D AMRAAM and shorter-range AIM-9X Sidewinder air-to-air missiles.
Development funding for the full Increment 3.2 was expected to begin in FY 2012, but current progress is unclear. What those upgrades will entail is also unclear. Increment 3.2 has run into problems, and is now split into a 3.2a (by 2014) and 3.2b (by 2017), while costs rise and delivery dates slip. There may be even a hardware focus at the end of Increment 3.2, if a USAF effort to examine the full replacement of the F-22’s core systems with a modern, open architecture software and hardware framework (vid. the F-35) bears fruit. If the idea looks affordable, it could become Increment 3.2c, for installation by 2020.

I believe around 40 Block 10 F-22s are being used in training, the remaining aircraft aren't all equipped to the same standard and, consequently, have different combat capabilities. I don't know what fraction of the remaining ~147 Block 20-andor?-higher F-22s is currently fitted with the latest equipment.

 

[Triton]

"US Air Force chief rejects pilot blame in F-22 crash"
http://www.flightglobal.com/news/articles/us-air-force-chief-rejects-pilot-blame-in-f-22-crash-369194/

 

[kulus]

RED FLAG

http://www.youtube.com/watch?v=7X-F1jNRAzc&feature=player_embedded#!

 

[flateric]

...

 

[F-14D]

I was referring to the reports that around 40% of them aren't really capable of going into combat, since they lack the proper systems to do so. Once again, like the F-35, they were put into production before being ready and now have to be rebuilt to have the systems added to make them effective. The purpose of concurrent engineering is to build enough of them before it's too late to cancel them.

Sounds like you are mixing numbers. 60 % is what the rate of combat readiness is for F-22. Meaning out of 10 planes, 6 can fly on a relatively short warning.

Sundog may be referring to the various F-22 blocks and their capabilities. I found this at Defense Industry Daily

Even though the F-22 is going out of production, the program itself will continue to attract spending on maintenance, spares, and upgrades. Right now the Air Force operates mostly Block-10 and Block-20 aircraft. The Block 10s are used for training at Tyndall AFB. The Block 20s use “Increment 2” hardware and software, which lets them launch JDAM bombs, and improves performance with the AIM-120C AMRAAM.
Under the Common Configuration program, the F-22A Block 10s will be upgraded to Block 20 status, but retain the original core processor. They’ll have operational capabilities, but present plans call for them to be used mostly for training. The Block 20 jets will get upgrades to the F-22A Block 30 configuration, and can then receive additional Increment 3 upgrades.
By 2016, the Air Force should have 34 Block-20 Raptors, 63 F-22A Block-30s, and 87 F-22A Block-35 aircraft. Only the Block 35 jets will be capable of using Increment 3.2 capabilities, unless the F-22’s avionics receive an open architecture makeover that brings down upgrade costs.
Increment 3.1 was set to begin OpEval in January 2011. It includes ground-looking synthetic aperture radar (SAR) modes, some electronic attack capability, geo-location of detected electro-magnetic emitters, and initial integration with the GPS-guided GBU-39 Small-Diameter Bomb (SDB-I). That last change expands the F-22’s ground attack arsenal from 1 JDAM per bay to 4 SDB-Is. The catch is that a pilot will only be able to release 2 weapons at a time.
Increment 3.2 will be a software-focused upgrade, and was expected to begin in 2014. It will provide compatibility with new AIM-9X Sidewinder short range air-air missiles, and the AIM-120D medium range air-air missile whose range, 2-way datalink, and AESA friendly features appear to be tailor-made for the F-22. MADL datalink upgrades would let the F-22 work better with other platforms, while improved emitter geo-location, improved targeting capabilities, better jamming resistance, Link-16 track fusion, and Automatic Ground-Collision Avoidance System (AGCAS) round out the electronics upgrade highlights. Under 3.2, pilots will be able to release all 8 SDB-Is at once, and the jets will receive full compatibility with the advanced AIM-120D AMRAAM and shorter-range AIM-9X Sidewinder air-to-air missiles.
Development funding for the full Increment 3.2 was expected to begin in FY 2012, but current progress is unclear. What those upgrades will entail is also unclear. Increment 3.2 has run into problems, and is now split into a 3.2a (by 2014) and 3.2b (by 2017), while costs rise and delivery dates slip. There may be even a hardware focus at the end of Increment 3.2, if a USAF effort to examine the full replacement of the F-22’s core systems with a modern, open architecture software and hardware framework (vid. the F-35) bears fruit. If the idea looks affordable, it could become Increment 3.2c, for installation by 2020.

I believe around 40 Block 10 F-22s are being used in training, the remaining aircraft aren't all equipped to the same standard and, consequently, have different combat capabilities. I don't know what fraction of the remaining ~147 Block 20-andor?-higher F-22s is currently fitted with the latest equipment.

Some observations, in no particular order.

Unless something has changed in the last few weeks, F-22 will not be getting MADL. Until some as yet not defined future system gets installed, the only way a F-22 can transmit to anything except another F-22 is by non-secure voice. The BACN relay plan is sort of a Goldberg type workaround.

It's not that under Increment 3.1 an F-22 can only drop two SDBs at a time. My understanding is that it can use all eight if it wants to, but can only attack two fixed targets in a single sortie. 3.2 should fix that and it is planned to be applied to the Block 30 and 35 units, numbering 150 (if that doesn't get cut). The non-comba coded aircraft will be brought up to Block 20 standard.

Increment 3.2 allows F-22 to use AIM-120D, and will allow AIM-9X to be used in HOBS mode (but still no HMCS). That should start around 2017. It will also allow the Raptor to retarget all of its SDBs in flight.

Increment 3.3 is not yet funded or fully defined. Despite what the article indicates, I don't believe JHMCS is planned for Raptor, although I'd love to be wrong (again). The issue is not software, but rather "mappng the F-22's cockpit".


BTW, the date of the article you linked to was March 29, yet you posted on February 23! ??? Has the Doctor been loaning out the TARDIS, or are you secretly the new Companion?

 

[Arjen]

@F-14D: I linked to the DID-piece because it illustrated the various equipment levels of F-22s. Thank you for providing more information.

BTW, the date of the article you linked to was March 29, yet you posted on February 23!

Has the Doctor been loaning out the TARDIS, or are you secretly the new Companion?

I offer two possibilities:
1. somebody at DID has been playing with the article date
2. the Doctor made me forget - he does that sometimes, right?

 

[Grey Havoc]

Courtesy of the Washington Times:​

**FILE** An Air Force F-22 Raptor executes a supersonic flyby over the flight deck of the aircraft carrier USS John C. Stennis in the Gulf of Alaska. Production will be stopped at 187 Raptors. (Associated Press/U.S. Navy)

 

[Triton]

Drewl!

Source:
http://www.flightglobal.com/blogs/the-dewline/

 

[sublight]

F-22 pilots speak out on the OBOGS problem......

http://www.cbsnews.com/video/watch/?id=7407680n&tag=contentBody;storyMediaBox

 

[Triton]

"US Defence Secretary orders additional F-22 safety measures"
By: Dave Majumdar Washington DC

Source:
http://www.flightglobal.com/news/articles/us-defence-secretary-orders-additional-f-22-safety-measures-371943/

US Secretary of Defense Leon Panetta has directed the US Air Force to take additional steps to ensure the safety of pilots flying the Lockheed Martin F-22 Raptor.

Pilots operating the stealthy twin-engine air dominance fighter must remain close enough to an airfield to recover the aircraft quickly in case they encounter problems with their oxygen system.

"All F-22 flights will remain within proximity of potential landing locations to enable quick recovery and landing should a pilot encounter unanticipated physiological conditions during flight," says acting assistant secretary of defense George Little. The order is effective immediately, he adds.

The Department of Defense says that the order is open-ended until Panetta believes that problems with the F-22's oxygen system are mitigated. Pilots flying the aircraft have been afflicted by a number of incidents that resemble hypoxia, but the USAF has yet to find the root cause of the problem.

The USAF says it believes that it has narrowed the potential source of the jet's woes to either a toxin or to the quantity and quality of oxygen flow to the pilot. Decompression sickness has not been ruled out however, the service says. Sources say that the problem could be an insidious form of hyperventilation-if it is not a toxin.

The aircraft was grounded for four months last year due to 14 such incidents which have occurred since 2008. The USAF resumed flying the jets last September despite the fact that it had yet to discover the root cause of the problem. There have about a dozen incidents since the grounding was lifted.

In recent weeks, a number of pilots have refused to fly the F-22 including two aviators who appeared on national television in order to draw attention to their plight. Panetta's decision was due in part to the two men's television appearance.

There will some impact to the Raptor's operations due to the new safety measures. Panetta's order will not affect the 7th Fighter Squadron which is currently deployed to Al Dhafra in the United Arab Emirates. But the directive will impact domestic flights in Alaska.

For the 3d Wing and its reserve associate 477th Fighter Group, based at Joint Base Elmendorf-Richardson, Alaska, the order means that the units will not be flying long-range air sovereignty missions, Little says. Other aircraft will pick up the slack.

Additionally, Panetta is ordering the USAF to speed up the installation of an automatic backup oxygen supply into the entire F-22 fleet. The USAF should complete testing of the automatic backup oxygen system by the end of November. Installations should begin in December with 10 Raptors being retrofitted with the system per month. The USAF has 185 operational F-22s and a handful of test aircraft in its inventory.

Panetta is also directing the USAF to provide him with monthly updates on the service's progress in determining the root cause of the jet's oxygen system maladies.