F-35 Down at Eglin AFB

Again glad the pilot is alright.

Unfortunately a 90M dollar oops. Although, the aircraft has been at Eglin almost 10 years now without incident and I believe this is the first one the USAF has lost. USMC lost one to a fire at Beaufort and I think there was another loss somewhere. Not a terrible record for the aircraft in all. Hope they find the cause.
 
USAF lost an early bird to a ground fire after an uncontained turbine disk failure. USMC lost the one to an inflight fire.
 
Glad pilot is OK. Yeah, $80 million. But given the capabilities needed in fighter aircraft in these times, I think this is just the cost of doing business in the military today. Freedom isn't free or something like that.
 
Betther than the $150 million+ they were going for originally. And at least the production line is still open for these :rolleyes:
 
The 58th at Eglin is a graduate maintenance and training squadron, meaning you go there for your " F-35 type rating".
 
Good to hear the pilot is OK never good to loose an aircraft.
 
The second article states $175 million loss which is a number closer to what I have read. Almost makes going to war too expensive.
 
Automation and integrated systems are great when they work.

On the other hand...
 
I’m wondering why just looking out the window wouldn’t have told the pilot that he wasn’t flared adequately.

Was that crash at nighttime? It mentions a poorly lit airport, but I saw no mention of nighttime.
 
NoHeat said:
I’m wondering why just looking out the window wouldn’t have told the pilot that he wasn’t flared adequately.

Was that crash at nighttime? It mentions a poorly lit airport, but I saw no mention of nighttime.
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I believe a saw reference to returning from a nighttime training mission...although returning from said mission certainly could’ve been during daylight or dawn.
 
A technology caused accident. With that much technology, confusing and second-guessing the pilot, the damned plane might as well be a drone.

I wonder which generation of the Vision Systems HMD the pilot was using? The original generation exhibited the exact problems the pilot experienced. I think they are now up to gen 3 or 4.

And what "human factors" idiot thought oxygen on demand, read that "resistance to inhalation" was a good idea? Fire that person. This is a well-known issue in underwater diving--SCUBA and rebreathers.
 
Getonit said:
The second article states $175 million loss which is a number closer to what I have read. Almost makes going to war too expensive.
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The earlier production airplanes, which this one was, were more expensive then the new ones coming off the line today.

Domenick said:
And what "human factors" idiot thought oxygen on demand, read that "resistance to inhalation" was a good idea? Fire that person. This is a well-known issue in underwater diving--SCUBA and rebreathers.
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That has been standard on regulators for a long time - you can kick it into pressure breathing if necessary but I don't think the pilots are required to do this except in certain instances. Maybe one of our mil flyers can speak to their SOPs.
 
Seanaldinho said:
The earlier production airplanes, which this one was, were more expensive then the new ones coming off the line today.
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Somewhere, there is an accountant writing up a report that the more early production F-35's we lose, the more money we save because the new production planes cost less to acquire.
 
Seanaldinho said:
...That has been standard on regulators for a long time - you can kick it into pressure breathing if necessary but I don't think the pilots are required to do this except in certain instances. Maybe one of our mil flyers can speak to their SOPs.
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The legacy O2 regulator panel SOP is Normal/Normal/On. In the mask, not much effort is needed to breath in that configuration. Rapid Depressuration is to gangload to Emer/100%/On which results in positive rate 100% O2 being fed to the mask and requires a forceful exhale against the pressure. That setting isn’t designed to be used for extended periods.

e968eccd9c8bebed49be106258fb6c72.jpg


The F-35, like a lot of other modern fighters uses OBOGS instead of LOX, which can create it’s own set of problems in O2 delivery. Here’s a decent paper on some of those.

https://www.airuniversity.af.edu/Portals/10/ASPJ/journals/Volume-33_Issue-3/F-Elliott_Schmitt.pdf

What I don’t know is whether the F-35 uses the legacy regulator which may not be the source of the increased work of breathing that OBOGS can result in, or if it uses an electronic regulator. @hindsight2020 or one of our other current mil aviators will have better info though.
 
TCABM said:
The legacy O2 regulator panel SOP is Normal/Normal/On. In the mask, not much effort is needed to breath in that configuration. Rapid Depressuration is to gangload to Emer/100%/On which results in positive rate 100% O2 being fed to the mask and requires a forceful exhale against the pressure. That setting isn’t designed to be used for extended periods.

e968eccd9c8bebed49be106258fb6c72.jpg


The F-35, like a lot of other modern fighters uses OBOGS instead of LOX, which can create it’s own set of problems in O2 delivery. Here’s a decent paper on some of those.

https://www.airuniversity.af.edu/Portals/10/ASPJ/journals/Volume-33_Issue-3/F-Elliott_Schmitt.pdf

What I don’t know is whether the F-35 uses the legacy regulator which may not be the source of the increased work of breathing that OBOGS can result in, or if it uses an electronic regulator. @hindsight2020 or one of our other current mil aviators will have better info though.
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Yeah, that's the reg I used in my chamber training. Pressure breathing certainly wasn't comfortable for normal use and I never felt any issues getting oxygen in the normal setting.

I was more trying to say that I don't think the regulator/on demand oxygen is the issue as the other poster was implying - it is something else in the OBOGS.
 
Seanaldinho said:
... I was more trying to say that I don't think the regulator/on demand oxygen is the issue as the other poster was implying - it is something else in the OBOGS.
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The paper I linked goes into a good discussion on the systems as well as Physiological Events in tactical aircraft with OBOGS.
 
TCABM said:
What I don’t know is whether the F-35 uses the legacy regulator which may not be the source of the increased work of breathing that OBOGS can result in, or if it uses an electronic regulator. @hindsight2020 or one of our other current mil aviators will have better info though.
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I am indeed familiar with the literature you posted, since we were in the thick of it during the 2016-2018 time frame in the T-6.

To your question, the regulators between the two systems perform the same functionality. They provide forced pressure on EMER setting (red lever) in order to keep positive pressure against smoke and fumes, and/or additional PaO2 equivalent during cabin decompresion above angels 25 cabin. At any rate, the only difference between the two systems is that in the case of OBOGS, the electronic concentrator provides different O2 effective concentration schedule (lever typically labeled MAX) than what the 100% concentration setting of the LOX-system associated regulator provides us. This is largely due to the supply mechanisms of oxygen being different in OBOGS (electronic cyclic multi-membrane/chamber concentrator) vs LOX (knuckle dragger diluter with no electricity nor aircraft pneumatics required).

I've flown both. OBOGS scares me on an occupational health basis, long term. Properly maintained and early-overhauled, I'm otherwise comfortable with the exposure risk to hypoxia and carcinogenic stuff coming from the "magic membranes" if failed. Unfortunately, that's not how the DOD rolls. Indentured servants don't get transparency, and I digress before I get talked to again. I'm under no illusion that whistleblowers get any kind of reprieve in the military. There was plenty of evidence of what befalls you when you choose that route, by the experience one of the two Guard F-22 pilots back in 2011. Nothing new under the sun. 6.5 years to check o the month....

LOX may be testy for mishandling by the maintainers (anything that can go kaboom is), but it's the devil I know, so it's the devil I trust. Worst I can have with LOX generally, is the old POS regulators leak like a russian bot if you leave it out of 100%. So you get stuck on a RON waiting on the OG/CC to get ya the waiver to fly it to a servicing base while remaining below 10K. Big whoop. By the way, our regulators (same one you posted) are safety wired ON, so we never manipulate the green lever. In the OBOGS bird, they're electrical dependent, so the switch had to be manipulated on and off. You also need pneumatics with obogs, so that's a system limfac in the event of engine failure. Granted, on the grey jets, you got RAM alternate sources and/or multiple engines, so it's not a limfac for them as it is for the T-6.

--break break--

None of this has anything to do with what happened with this F-35 in my professional opinion.
 
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^ yeah I agree with this being irrelevant to the topic at hand.

For what it is worth, OBOGS is beneficial in that it provides on demand O2 for the extremely long missions we have been flying over the last 20 years. No chance your low lot LOX Hornet (as an example) was going to keep pumping out much more than about 2-3 hours of the stuff, which doesn't do much good on an 8+ hour sortie. I'd take LOX all day and every day stateside when you are flying a 1.3-2.0 (or often less). I'm pretty convinced the fact that I had been pre-breathing 100% LOX for about an hour prior to my most recent rapid decompression, was the reason I never had any physiological symptoms.....this was at FL420 and the cabin dumped to basically ambient pressure in about 2 seconds. Or maybe it was all the years I had flown legacy Hornets where the cabin pressure needle swung +/- 3000 ft cabin pressure continuously for a whole flight that conditioned my body to have no response :)

The OBOGS stuff was real, and it likely is harmful in the long term due to the filtration issues hindsight mentioned, but it does have a purpose. It just isn't as nice as LOX for a lot of reasons.
 
hindsight2020 said:
I ...

None of this has anything to do with what happened with this F-35 in my professional opinion.
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35 AoA said:
^ yeah I agree with this being irrelevant to the topic at hand.
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I never flew OBOGS so thanks for the fill ins, as they all make sense.

The only reason OBOGS came up was it’s listed as a contributing factor in the public report based on MP interview and comments about being fatigued. Wish I could the SIB report still.
 
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