Home » Aviation » Recent Carrier Deployment Raises More Questions About Navy’s Rash of Physiological Episodes


Recent Carrier Deployment Raises More Questions About Navy’s Rash of Physiological Episodes

An F/A-18C Hornet attached to the “Raging Bulls” of Strike Fighter Squadron (VFA) 37 launches from the aircraft carrier USS George H.W. Bush (CVN 77) (GHWB) as an EA-18G Growler, attached to the “Lancers” of Electronic Attack Squadron (VAQ) 131 prepares to launch on April 8, 2017. US Navy photo.

The Navy is grappling with even more questions about the physiological episodes its fighter pilots have been facing, after Carrier Air Wing 8 deployed with additional tools to measure and treat PEs and returned with less clarity on the connection between cabin pressure and physical side effects.

In April the Navy directed a 30-day comprehensive review of physiological episodes, which led to the requirement to have a single aviator leading the investigation effort for the Navy. In August Capt. Sara Joyner was tasked with leading the PE investigation effort.

Joyner and Carrier Air Wing 8 commander Capt. James McCall spoke to two reporters today to talk about the progress in studying, measuring, treating and attempting to predict physiological episodes – which include decompression sickness from pressure fluctuations or hypoxia from insufficient or contaminated oxygen.

A major ongoing challenge, McCall said, is that a physiological event is defined not by cabin pressure or oxygen levels, but rather how that environment affects the body – and there are so many variables at play that the Navy still doesn’t have a good understanding of what combines to create a harmful situation for a pilot’s body.

“I have watched what I would consider to be the exact same pressure profiles on the slam stick affect two different aircrews completely differently,” McCall said, referring to a USB stick-sized device that precisely measures and digitally records cabin pressure throughout a flight.
“In one case, completely asymptomatic on the aircrew, he didn’t even feel the need to report anything, he just felt very normal. And the other aircrew we ended up sending to a hyperbaric chamber – for the exact same pressure profile that was not even outside the aircraft limits.”

“The pressure swing was not what we would consider to be outside NATOPS (Naval Air Training and Operating Procedures Standardization) limits,” McCall added later in the interview.
“The aircraft had flown earlier in the day with another aircrew and exhibited the same profile that we pulled down digitally for pressure, and that aircrew was completely asymptomatic. So again, I think that actually highlights what a challenge it is when we look at the human body, trying to figure out … not only how we diagnose things but how we prevent them. Because again, we looked at the profile that we pulled off that piece of gear … and we had almost the same profile on two different pilots in the same aircraft, and one of them, he went on to fly later that day, no symptoms at all, and the other aircrew, again, post-flight started to complain of symptoms that we would consider to be [decompression sickness]-like, and then upon consult with our flight surgeons and our dive docs, that’s when we decided to put that aircrew in the portable recompression chamber.”

An F/A-18C Hornet assigned to the “Ragin’ Bulls” of Strike Fighter Squadron (VFA) 37 prepares to land aboard the Nimitz-class aircraft carrier USS George H.W. Bush (CVN 77) in the Atlantic Ocean during exercise Saxon Warrior 2017 on Aug. 5, 2017. US Navy photo.

Overall, McCall said, his pilots experienced 13 physiological episodes during a seven-month deployment on aircraft carrier USS George H.W. Bush (CVN-77). Four of those incidents required putting the aircrew into a portable recompression chamber to recover, after several hours of breathing from an oxygen mask did not alleviate the symptoms. One of those four cases involved the two aircrew on an EA-18G Growler, who experienced decompression sickness-like symptoms during their return to the ship from a combat sortie. The other three involved fluctuations in cabin pressure that sickened F/A-18C pilots from Strike Fighter Squadron (VFA) 37.

Bush was the first carrier to deploy to a combat zone with a portable recompression, or hyperbaric, chamber to help treat decompression sickness symptoms.

McCall said the Navy has an effort underway right now to put jet aircrews – those who operate the F/A-18 Hornets and Super Hornets, the EA-18G Growlers and the T-45C Goshawk trainers – into ground-based simulators that would help them safely experience pressure fluctuations or low oxygen levels to understand how their bodies react and therefore what symptoms to be on the lookout for. But McCall added that lack of sleep, dehydration and other factors can influence the onset of these physiological episodes, complicating what the Navy is trying to do.

Vice Chief of Naval Operations Adm. Bill Moran previously told USNI News that “what we’ve got to get away from is reliance on [individual perceptions and self-reporting], and more from data. So putting sensors on these airplanes so we can collect data and get a richer understanding of what’s going on.”

Joyner elaborated on the effort to collect data, saying, “we are building a suite of digital information about the aircraft to understand what other things might be causing the physiological episodes. Because the human being is a complex system, there are many things to consider beyond just the oxygen content delivered, and therefore we are working with things like a slam stick, which is something that measures the cockpit variations in pressure down to 1 Hertz … in order to understand what is going on in the cockpit that actually results in a physiological episode.”

“Right now we’re writing a piece of code that will alert the aircrew, give them a visual indication that there was a boundary that was exceeded, so therefore they can be more vigilant in making sure if they feel any impacts reporting what they experienced,” Joyner continued.
“So digitizing the cockpit is a big initiative of ours in order to not only, we want to understand what causes physiological episodes but we’re also building to indicating, warning and preventing. So very important we understand what causes them. So in the future we’re working on putting in something called a Cockpit Pressure and Oxygen Measurement (CPOM) system, it’s going to be able to indicate digitally to the pilot what’s going on with his oxygen, with the pressure, and as we understand what causes physiological episodes it’s going to be able to give them warnings and cautions.”

Capt. Sara Joyner, then commander, Carrier Air Wing 3, on the flight deck of the aircraft carrier USS Harry S. Truman (CVN-75) in 2013. US Navy Photo

Joyner was also hesitant to call the pilots’ condition decompression sickness, in a nod to just how many factors are at play when studying PEs.

“It’s important to note that while we’re saying that maybe it’s pressure, there’s a lot of work to be done. We’ve gone through very methodically to make sure we’re not experiencing some other unknown factor here that’s impacting our aircrew – so we have gone down and researched contamination to an extreme depth to make sure there are no contaminants coming through to our aircrew,” she said.
“We have gone through and are also looking at the oxygen system to make sure that there’s no impact not being evident with the oxygen system. And then pressure is something we see, and it has an actual association (with the symptoms), but its actual causal nature is not established yet.”

Joyner added that the hyperbaric chambers helped the aircrew recover quickly the four times they were used, but deploying more of these chambers is not a viable long-term solution.

“The hyperbaric chamber is something we use, but it’s certainly not something we want to use forever or expect to – we expect to fix the machine and understand the human so we can move away from this type of care,” she said.

McCall made clear that he and his team managed the PEs during the deployment and did not let them affect the air wing’s ability to meet operational commander needs.

“In no way did this impact our ability to execute our operations on deployment. We were able to treat these – none of these actually happened on combat sorties or during the course of combat. They did not, in fact, put our aircrew down for any length of time that affected our combat operations, so we were able to adequately meet our commander’s operational requirement while dealing with these incidents on cruise. For our commanders, certainly they have to balance risk versus operational commitments, and I think we did a good job of that while deployed.”

Still, he noted, “employing combat requires our pilots to be at the top of their game, we need them to be physiologically ready to go. … What we don’t want is the airplane detracting from that in any way.”

  • Curtis Conway

    Naval Aviation is a hard enough job as it is, and the aircrews should NEVER have to deal with, much less worry about this kind of threat to their physiology. A review of all OBOGS technology, and re-compete of more solid and common devices on ALL platforms and implementation should be explored. Let us solve this problem once and for all, and supporting an average human body is not the goal.

    • Duane

      What the data show is that it is not necessarily any hardware issue at all that causes the PEs, but rather, the human performance factors are now being fingered. It is easy to declare that the hardware must work perfectly, but people are reluctant to admit to personal risk factors that might result in them getting grounded, or self-grounding.

      • Curtis Conway

        Well, there are another two DEAD (T-45 Instructor/Student) in Tennessee with which you can confirm that data. Better safe than sorry. Take care of the troops and they will take care of the tasking, and this is an All Volunteer Force. If the government does their part, the Patriots will do theirs.

        • Duane

          Dead pilots happen most of the time due to pilot errors. And many pilot errors are well documented to occur due to personal issues – their bodies, their minds, their circumstances.

          Waving a bloody body and attempting to shut off a reasoned and science based approach to elimininating PEis is brain dead and counterproductive.

          Read the article, Curtis. Two separate air crews, reacting to exactly the same physical conditions, one had a PE and the other didn’t. Neither PE occurred outside of any actual malfunction or out of spec measurement of the aircraft environmental systems. If you want to chase bogies and fake causes, fine, do so. But I am very happy that the Navy is doing better than that today.

          • Curtis Conway

            Between recorded incidents in the F/A-18/T-45/F-35 (even USAF) communities, one cannot just dismiss this all by saying HUMAN ERROR. Either the equipment is rock solid, the design is drop dead accurate and functional, and maintenance is well understood, and enough qualified parts & technicians to do the job are present . . . or not. THAT is not that hard to establish, unless you are trying to hide something. The US Navy is not the only service having problems with readiness due to lack of spare parts, qualified technicians (ready, willing & able . . . and RESTED I might add), and completed training that is more than a piece of paper, but rather a demonstrated capability. The F-18 numbers go back over a decade with a huge spike over most recent years. An operator of anything should never have to second guess his/her equipment.

          • Duane

            Nothing is being dismissed, except by you. PEs can result from equipment malfunction, but as I describe elsewhere in this thread, they can also result from many other things that have zilch to do with equipment performance. When the data shows, as reported in this post, that the equipment did not malfunction, that the required environental parameters were within spec, yet one crew experiencing these conditions had a PE and another crew experiencing the same conditions did not, then obviously it’s not equipment in those particular circumstances.

            With data – which you cavalierly dismiss – one can conclusively prove that other things – of which I described many above that are already very well known and understood to aviation physiologists -do in fact cause many, perhaps most of the PEs the Navy has experienced. Human beings are very complicated “machines”, far more complex than any built by man. With dimensions involving human behavior, mental factors, biochemistry, and so forth.

            The simple minded try to pretend everything is simple when it is clearly not simple. There’s a “bad guy” in the machine that must be found and discarded, or a naval bureaucracy to be blamed for not paying attention to pilots. When dealing with human-machine systems, it is vastly more complicated than that. Something as seemingly innocuous as an argument with one’s spouse or significant other can bring on a PE episode. Or worry about the student pilot’s ability to nail the carrier landing. Or the experienced ace pilot’s going too many hours without sleep over the prior week. Or an electrro-mechanical issue in the OBOGs. Or an over-the-counter drug that should not have been consumed to deal with a headache or cold symptoms,

          • Curtis Conway

            “…With data – which you cavalierly dismiss – one can conclusively prove…”

            I dismiss nothing, particularly data, and I will not drive the data to show what I want it to do, or look like . . . to support my supposition. However, if we manufacture a better, easier to maintain, more common between the airframes with interchangeable parts OBOGS units with a higher MBTF, then we can kill many birds with one stone. If G-d has shown me anything it is that He loves wondrous VARIETY, and there AIN’T NO SUCH THING as a Mk1 Mod0 human being. Each and every one of them are unique, with different characteristics, and THAT is what we have to work with. If the selection process has produced what we are having problems with today, perhaps part of the solution is the selection process. Ever since they took Louis Gossett Jr. out of the training process, I have considered it to be questionable.

  • RobM1981

    I presume that they are taking blood samples from every pilot, regardless of whether they are symptomatic or not? Full workups and not just blood gases. Control for gender, race, ethnicity, physical size, etc. The human is part of the system, as much as the machine. All of it has to be studied and optimized.

    I’d probably have the aviators conduct various tests, before and after flights, too. There are quite a few well documented tests for vertigo, cognitive abilities, etc. Again, everything has to be studied. This can’t just be a “so, how do you feel?” kind of thing. Aviators are aviators – if they aren’t dying, they are going to say “I feel great!”

    I agree with Mr. Conway, below – this is a hard enough task as it is. The aviators need a quick resolution to this.

    • Duane

      Blood samples collected after the flight can be mostly useless for understanding what is going on, physiologically speaking, in the air crew’s bloodstream during a high altitude flight. If there is a CO issue, that would persist after the flight is concluded, but by the time the crew lands whatever else might have been causing a lack of oxygen, or a lack of oxygen transfer, or insufficient CO2 in the blood, or mental stressors or lack or sleep or any other number or potential contributors, are no longer present.

  • publius_maximus_III

    “…therefore we are working with things like a slam stick, which is something that measures the cockpit variations in pressure down to 1 Hertz … in order to understand what is going on in the cockpit that actually results in a physiological episode.”

    Since pressure is normally expressed in units of psi, or bars, or inches (millimeters) of mercury, so should pressure variations or differences. That’s why the Hertz unit of measure is puzzling to me, since it is a unit of inverse time, i.e. frequency. So, is Captain Joyner looking into how rapidly the pressure fluctuates during certain maneuvers? Maybe whatever device (a compressor, an accumulator, a gas generator?) that maintains the desired pressure actually fluctuates between high and low pressure levels, so that an RMS or average pressure is maintained, but instantaneous pressure varies above and below that level? The longer the period of such fluctuations (the cited low frequency of 1 Hertz = 1 fluctuation per second), the longer the dwell time at the lower pressure level. Maybe the pressure is fluctuating faster than normal instruments are able to detect, but something a slam stick can pick up?

    • DaSaint

      I caught that also. It will be interesting to see if there are further explanations.

      • publius_maximus_III

        I think I miss-read her comment. She probably meant that the slam stick is capable of recording “instantaneous” cockpit pressures as frequently as once every second.

        Pilots obviously speak the language of clipped jargon. Recall Sully’s famous response on his way to the Hudson, “Unable.”

        • Duane

          Actually, “unable” is precisely the term that pilots are required to use when they are unable to safely do what a controller has asked or directed them to do, or if the aircraft is physically incapable of performing as directed. It isn’t “jargon”, any more than the proper response to a naval order (“Aye, aye, sir”) is jargon.

          Your corrected understanding of the term as you stated is correct – the frequency at which data are logged per second.

          • publius_maximus_III

            jar·gon
            [ˈjärɡən]
            NOUN
            special words or expressions that are used by a particular profession or group and are difficult for others to understand: “legal jargon”

            Non-jargon
            Police Officer: I’ll need to see your driver’s license and vehicle registration
            Driver: Yes sir.

            Jargon
            Officer: You men Flemish down those lines.
            Sailors: Aye-aye, sir.

          • Duane

            “Unable”and “aye aye,sir” are well understood. About as simple as it gets.

          • publius_maximus_III

            I was merely pointing out that for an average civilian such as myself, certain words used in aviation or marine contexts mean more than than they do in everyday life. If that’s not jargon, I don’t know what is.

            “Unable” is a very concise/precise response from a pilot to an air traffic controller, as you’ve noted. But try telling a traffic cop “unable” when he asks for your drivers license and you’re holding a lit cigarette in one hand and a coffee cup in the other, he may ask you to step out of the car. And unless you’re from Scotland, the word “Aye” is simply the opposite of “Nay” during a voice vote, whereas the “Aye-aye” used by the USN and USMC has a special meaning — that an order has been understood and will be carried out. “Yes, Sir” is the answer to a question, “Aye-aye, Sir” is acceptance of a command.

            I do acknowledge your experience and training as a private pilot, and found your discourse above on PE’s very informative. But I’ll go head-to-head with you any day on English grammar and diction. When’s the last time you diagrammed a sentence?

  • ADM64

    Why has this not been a problem in decades past? The Navy has been operating high-performance fighters for a very long time, including the F/A-18 that is currently the mainstay of the carrier air wings. But, this has only been cropping up in the last few years. What are the stats for this by age, gender, overall fitness?

    • Duane

      The Navy likely has always had PEs, but simply didn’t know it, going back to the first aviators at the beginning of the 20th century … but our understanding of human performance factors for most of the last 100 years has not kept pace with engineering design.

      When the documented issues with OBOGs cropped up, everybody became sensitized to the issue of PEs and reporting and awareness increased substantially. Pilots, like athletes, are reluctant to acknowledge that they are not operating at full potential – nobody wants to be grounded, or sitting on the sideline during a game. What the Navy is finding out now is that PEs are not just related to aircraft hardware, but to other things that affect human performance in a high stress environment.

      This isn’t surprising at all. What is surprising is that the Navy only begins to collect real time data now. The real time data are what allow the physiologists to drill down and determine, on a data-based approach, the factors that do affect human performance. Everything from a simple head cold to lack of sleep to job stress or personal stress, to more serious illnesses can cause a PE. If the result of this study process leads to better guidelines on when and how to fly, it will result in better performance and a better safety record. Perhaps even in-cockpit systems that can detect a potential human-sourced PE risk and say, “no go” when appropriate.

      • RTColorado

        Decompression Illness in aviators is a rare occurrence and the philosophy of treating vague symptoms is the safest approach, but can not be used as a data point in determining the rate of decompression Illness. Decompression Illness related to aviation exposures is a very real event and the question is whether this is a cluster anomaly or a trend.

        • Duane

          You’re confusing and conflating two very different phenomena,

          Physiological Episodes (PE) as defined in aviation use does not equate to “decompression illness”, which almost never occurs in aviation PE incidents. Decompression illness is defined as gas bubbles (nitrogen) coming out of solution from the blood and forming inside the body due to rapid depressurization, usually at joints, almost always occurring in some kind of diving accident. It is colloquially known as the “bends” and is very painful and potentially fatal, but has nothing to do with oxygen transfer to the body’s cells..

          PE incidents are incidents dealing with either reduced oxygen concentration in the bloodstream due to reduced partial pressure of oxygen at high altitude, or possible contamination that affects the ability of hemoglobin to transfer oxygen to the body’s cells (one example of that would be carbon monoxide “poisoning”). Lack of oxygen transfer can occur due to low atmospheric pressure from high altitudes, or a failure in an oxygen breathing system. But it can also occur due other causes.

          For instance, night flights reduce the effective pressure altitude, as far as how the human body works. Flights without supplementary oxygen are allowed by Federal aviation regs at up to 12,500 feet MSL, but supplemental oxygen for night flights is recommended at 5,000 ft MSL Being a smoker tends to restrict oxygen transfer. Stress tends to restrict oxygen transfer – and it is no accident that much of what occurs in naval aviation is stressful, be it training flights, or performing precise maneuvers, or combat. Many medications, both prescription and non-prescription are known to negatively affect oxygen transfer. And lack of sleep is also well known to affect oxygen transfer. ,Dehydration is also a contributor to PE, because aviators are typically breathing very dry air at altitude, so unless they drink plenty of water before and during flight, they become more susceptible to PE.

          Excessively rapid breathing rates (or “hyperventilation”) – which sometime occurs when some people are suffering stress or anxiety – depletes the CO2 concentration in the blood and that also causes a PE.

          Also, not being acclimated to high altitudes negatively impacts oxygen tranfer. It is well known that persons well acclimated to high altitudes, such as those living in the Rocky Mountain area, are much less susceptable to PE than are those acclimated to low elevations. Which means that nearly all our naval aviators, who live typically at sea level, are more susceptible to PE than are Air Force aviators who are based at facilities in the Western US at elevations of 5,000+ feet.

          • RTColorado

            Duane…you are much mistaken. I can refer you to any number of resources on Space and Aviation Medicine dealing with the incidence rates of Decompression Illness among aviators; crews and pilots. While there is a low incidence rate, it does occur across the spectrum of aviators for various reasons and from different sets of circumstances. Decompression occurs routinely in every aviator and crews, the difference are the episodes that result in symptoms. Symptoms varying widely, varying widely in methods of resolution and the degree of resolution. My comments address the comments made by CAPT Jaynor and what the Navy is doing and what they may need to do in the future. As to your comments about “PE” and hypoxia…a clinical decision point in disecting differential diagnosis is onset of symptom, duration and resolution of symptoms. There isn’t near enough information in the article to do anymore than speculate. In “austre environmental medicine” there are sets of circumstances that are direct cause and effect, but just as many are complex interactions of multiple events. Decompression Illness may be the result of “occult bubble” formation, but it can be the result of a cascade effect of compliment activation resulting in inflammatory responses, local hypoxia with neurologic effects. The “Rule of Thumb” among avaiation cases is pilots more commonly suffer symptoms from the waist down, suggesting body position, pressure suit, etc may play an addition role, while among “water divers” suffer from the waist up. None of this makes symptoms exclusive to one type or the other, but the routine is enough to have “Rules of Thumb”. There are so many derivations on cause and symptomology it takes a “longitudinal” approach to find the culprit…the Navy needs to look at the data very carefully given what the impact might be, but they place some simple “intermediate remedies” in place while they search for a possible cause.

          • Sapulpa

            I don’t know enough to weigh in on the subject, but I’m sure learning a lot reading you two debate the issue. Thank you RT and Duane!

          • RTColorado

            Duane is a pretty sharp cookie.

          • Duane

            Thank you, RT.

            I was not a naval aviator, but I have been a licensed private pilot for over 40 years, and have done a fair amount of flying cross country at relatively high altitudes in the Rocky Mountains of New Mexico and Colorado in an unpressurized aircraft, usually flying solo. So I made a point of learning about hypoxia and what causes it and how to prevent it. All pilots, private, commercial, and military get training in hypoxia, how to recognize it and how to prevent it. But PE incidents still happen anyway, some of them resulting in fatal accidents

            Given that two of the chief symptoms of hypoxia include loss of brain function, coupled with a general sense of well-being (sort of akin to an alcohol buzz), there is likely a pretty sizable proportion of pilot error-based aviation accidents that were in fact caused by or contributed to by flight crew hypoxia.,

          • El Kabong

            Just don’t mention LCS…

          • RTColorado

            Copy your last, Roger.

          • Duane

            No – you are confusing the term “decompression illness” with PE. They are not interchangeable, and no, very very few aviators experience the bends. Many many pilots experience PE episodes.

            Decompression illlness is specifically defined as nitrogen gas bubbles coming out of solution in the blood resulting in the “bends”. It has exactly zero, zilch to do with oxygen deprivation.

    • Curtis Conway

      OBOGS was the change. As Duane will tell you, PEs have been with us for a long time, but when your breathing pure O2 as opposed to generated O2, there is a difference in the quality of the Oxygen.

      • El Kabong

        Which is?

        • Curtis Conway

          Pure O2 is exactly that (Oxygen). Generated O2 must deal with everything that is introduced into the purification stream.

          • El Kabong

            So what are the impurities in OBOGS generated O2?

          • Curtis Conway

            Whatever happens to be in the ambient air that was not removed by the process of seperating the Nitrogen.

          • El Kabong

            So why don’t you find out what, if any impurities are making it through the system before condemning it?

          • Curtis Conway

            Well now, let us analyze what you are suggesting as we consider this very important issue. Samples are not taken and stored by any OBOGS unit of which I am aware. I am unaware of any OBOGS unit that conducts a chemical analysis of what is coming into the system to the point that a chemical other than O2, N2, and a little Ar are even considered. There are no other sensors, components, molecular sieves, or filters that take out anything else. NONE! The assumption is the intake air is low pressure air coming off the compressor that is AMBIENT air (mostly 21% O2, 78% N2, and trace elements of other things, mostly Argon). Well, if something else is out there . . . how would you know? How long has it been there? Was this just a short term transient event? What concentration was introduced to the crew in the OBOGS system that just hitched a ride through the system? AND almost all the OBOGS units out there JUST meet the need with very little safety margin (read excess capacity). There are a plethora of chemical molecules that can have a toxic affect on the human body at VERY LOW concentrations, so there you go. Now, make your own case.

            Additionally, one of the most debated issues, and still misunderstood regulations in the FAA is just how much O2 is enough given any situation. The current line in the sand is anyone (pilot in command) over 10K feet must be on O2 in an un-pressurized environment. The human body is NOT a Mk 1 Mod 0 construct, meaning every physiology is different even though they all work the same way. We even have scientist and engineers referring to O2 as a flammable gas in the documentation. NO, there are so many variables in this equation, with the analysis taking a very simple approach concerning input into, and output there of, is ALWAYS the same (mostly 21% O2, 78% N2, and trace elements of other things, mostly Argon), where that is actually an unknown, and/or just an assumption.

          • El Kabong

            Meanwhile, European OBOGS don’t have issues…

          • Curtis Conway

            I expect they have a significantly different design and performance with greater excess capacity. All in all, we have to identify and fix the problems. That will take time, and a new re-compete for an 18 month installation time for same form-factor and function would save a lot of that time. It would also give the manufacturers an opportunity to provide a superior product that I am sure they already have on their shelves. Industry leaders in this arena are not totally clueless in this regard concerning their product, its potential flaws and required improvements, of which you just pointed out, and I’m sure stand ready to solve the problem. Why delay the solution? It impedes readiness, and extends the casualty list.

          • Curtis Conway

            The point is that reserve O2 capacity in all OBOGS units is marginal. Throw anything into the mix that can have a negative affect and we have an endangered aircrew. As I have said many times . . . we need a new competition for more common equipment across all platforms that has a much higher reliability (MBTF), modular in nature and is easier to maintain, and has significantly more capability (reserve capacity). The re-compete could happen in 18 months or less, and back-fits to occur before the end of the next decade.

          • El Kabong

            Can’t answer the question?

  • honcho13

    Maybe that “jump” to autonomous aircraft isn’t as far off as we think! The “health-and-well-being” of the pilots could be the tipping point! Especially, if it is found that there is really no way to keep pilots safe in an inherently dangerous environment. Ah, the price of progress… MMCS(SW), USN (ret)

    • El Kabong

      Oh, good grief….

      Show me the UAV fighter that can do ACM, to replace manned fighters.

  • George Hollingsworth

    Does anyone have the confidence that the OBOGS system has been fixed? I don’t. In WW II aircraft the pilot had a diluter/demand system. In the diluter mode the oxygen concentration increased as the cockpit pressure inside decreased as the aircraft climbed. In the 100% oxygen mode the pilot received just that. Aviator Breathing Oxygen has a specific mil spec with the gas being over 99% pure oxygen with strict trace gas and moisture limits. The OBOGS system treats engine bleed air and doesn’t come close to Aviation Breathing Oxygen requirements. Enough is enough.

    • El Kabong

      What does “engine bleed air” consist of?

      Want to chat about the hazards of LOX?

  • Joe Tenaglia

    Obviously one cannot rule out anything including sabotage. Many DOD components have been procured from foreign sources. Backdoors, malware, logic bombs a problem.