Worse. It was 45 minutes of exposure to 12,500' after 45 minutes of exposure to 10,000'. And performance was measured during the hypoxic condition and descent, not after.
Wait…..you stop by FTG aka CFO and don’t tell anyone? We are in dire need of a POA get together now that Mari, Clark and Mark moved, Mike stays in Texas, and Nate ain’t flying these days.
How did you know I also fly a J-3 for fun (and to stay sharp)?
).
I'll go with Dr. Bruce. He actually knows this stuff.
Completely unnecessary to take his word and even more unnecessary to make an announcement of it, when you could read the paper and see for yourself that it does not support his claims.
Perhaps your appeal to authority was intended to be comedic. If not, a link to the study has been posted on the thread. It's all in plain English; you should be able to read it and draw your own conclusions.
He doesn't know this stuff. He's got an impressive CV and it's inexplicable how he is relating an unpressurized study to a pressurization incident. He actually posted that a loss of O2 in his unpressurized Seneca would be an emergency. It would be but has no relevance to the thread. He claims he doesn't know what O2 system the KA pilots had but all who fly pressurized A/C know there would most likely be diluter demand masks to be donned in about 15 seconds. What transpired in the King Air for 45 seconds that allowed the Garmin system to take over? I would not blame the KA crew for delaying the descent to try to salvage cabin pressure and continue the mission. They had no pax at risk. It is also possible that they delayed because putting masks on and establishing coms can be a problem if you haven't been well trained in doing it. We have 2 allegations in the thread about hypoxia. They have not been substantiated.
They didn't just sit there for 45 seconds, or at least there's no such indication from the ADS-B data. It's possible that they did nothing and kept climbing for 45 seconds and the Garmin initiated the descent, or it's possible that the pilots initiated the descent and the Garmin took over after 45 seconds. Once the CABIN PRESSURE message comes on, only one thing will keep the Emergency Descent Mode from activating, and that's a double-press on the A/P DISC.
Well, what a coincidence... of course I had no idea, but it stands to reason given what you posted.
I totally agree with you. As much as I like flying light aircraft, VFR, radios off, cavorting among the treetops and/or puffy cumulus, Mach 0.1 with my hair dancing in the slipstream of an open cockpit, I also enjoy the sense of reward and fulfillment that comes from a well-planned IFR flight, especially one that includes challenging weather, airspace, and procedures. And yes, I tended to hand-fly far more than my colleagues.
My biggest concern, as a GA pilot, is politics. Unfortunately, I can't share your optimistic perspective that your J-3 will always fall under an exemption of some kind.
There's the rub. Will computers, as we now know them, ever be able to synthesize the way that the human brain does, such that the machine can successfully create a solution to an unprecedented set of circumstances that were not accounted for by the programmers? No. But then again, it's really about economics vs. probabilty, and I'm guessing that we will reach that threshold relatively soon. In the case of the King Air that landed itself, the autopilot responded to a set of conditions that the programmers assumed would correspond to pilot incapacitation. The decision was predetermined by the programmers. And it worked, this time.
That's airmanship in action. I'm glad you and others have not given-up on it.I never could understand "children of the flight director" either...I try to fly raw data approaches from time to time just to keep skills from decaying, and because it's fun to do when the workload is light enough (or when I really don't like how the AP is flying S-turns down the FAC...maybe that's what the S in S-tec stands for?
It's not an appeal to authority. I read the linked study. Dr. Bruce has the right of it in my opinion, however that is far from my area of expertise. I'll take @Dr. Bruce's interpretation over some random dudes on the internet with no background in the area. Using a low partial pressure of oxygen as a proxy to actual low pressure is fine by me and makes sense chemically.
I find it interesting that no one has even implied that they tried to accomplish the procedure out of the supplement.
Your understanding of the study indicates a lack of understanding of it and it's relevance to the King Air occurrence. They did not use a low partial pressure as a proxy. They used a lower percentage mixture as a proxy for the four altitudes. We agree that is a proxy when you don't use an altitude chamber. While I am random I do have related background. A ride in the chamber a long time ago. Unpressurized flight to 250 with O2 (can't remember if we went 100%) with a bunch of spin recoveries on the way down. Airline training that allowed us to remove masks at 10. But Dr. Bruce is right about degradation at 12500 unpressurized. As I said, the colors become brighter when you put the mask on at 12000 plus or minus to land at La Paz. But he hasn't given us any study of forebrain insult in the 15 seconds of high altitude decompression before you are on O2 at 100% and if there was an insult whether 100% on the way down would clear it up by 10 or by the gate.
What is that procedure. If Garmin does the descent do you have to let it land also? I did ask this question in post #100: "I would expect an emergency descent would be self-initiated quicker but does King Air have some procedures and com changes that would keep them busy. And how would the system know you had already started the descent?"
Yep- a lower partial pressure. Partial pressure is the pressure a single gas would exert if it occupied a gas mixture's entire volume alone, described by Dalton's Law of Partial Pressures. You should have learned this in high school chemistry.
Without weighing in on anything else, I just want to point out that you can't just change the partial pressure of one gas without inadvertently changing the overall physiological effects of the remaining gases in the new mixture. Whether the resulting physiological effect is negligible or very significant depends on a bunch of factors that are not always fully understood, but as one example look at why Trimix is required at high overall gas pressures -- even though the partial pressure of oxygen is kept in the "normal" range, the other gasses (nitrogen) in standard air start to have deleterious effects without adding helium to the mix. Also, think about the partial pressure of e.g. CO2 -- in a true decompression situation, that goes down too (presumably aiding clearance of CO2 from the body?), but if we just reduce the oxygen mix at STP the CO2 (and N2) partial pressure remains the same.
"Simulated Altitudes Various reduced oxygen breathing mixtures (Primary Standard purity, ± .05 %) were used to simulate the following altitudes:
Good question. Nobody seems to know, which indicates even more that they weren’t following it.
What's your point? They used a lower partial pressure as a proxy for a reduced actual pressure. As I mentioned, Dalton's law of partial pressures allows the substitution.
Yes reduced percentage results in lower partial pressure and is an acceptable method if you don't have an altitude chamber. But we digress. The Nesthus study has no relevance to the King Air occurrence.
I don't have the background to fully assess that. However, neither do you.
A lower percentage mixture is a partial pressure. I note that you backtracked in your later posts and allowed that it is, but only after someone reminded you about Dalton's law.
Thanks for the reminder.
I do. The necessary background is a thorough understanding of English and basic science. There was no test condition in that study that was remotely similar to what occurred here.
Who here is a psychiatrist?
I'm thinking Bruce, but I could of course be wrong.
"and I guess now brain function with a psychiatrist"
Nope! I'm saying that a layman discounting an argument about human performance in a reduced oxygen environment and their recovery by someone that earns their living based on their understanding of human physiology is, to me, humorous.
Which procedure are you referring to? The A/P DISC double-tap?
No. In fact, the autoland system isn't enabled until after the EDM has leveled off. Then there's 0-15 seconds with a new CAS message (varies by manufacturer as they've all branded it differently) where the pilot is once again given an opportunity for the double-disconnect before the autoland is activated.
After reading the docs again, I don't think the system cares if you've initiated the descent. It only cares whether or not you double-pressed the autopilot disconnect. I believe that in this instance, the pilots did initiate the descent, but then let the system take over.
Aviation puts a lot of type-a folks with a god complex in one room.
www.logicallyfallacious.com
Nothing humorous about intellectual dishonesty or ad hominem attacks.
The Cabin Decompression procedure (or whatever it’s called in that airplane.)
Every forum has, among its collection of usual suspects, various experts, a couple of know-it-alls, and one Village Idiot. Here, I am The Idiot (but I do aspire to rise to the rank of Unwashed Layman). That's why I ask questions, such as "The purpose, methodology, procedures, findings, and conclusions published in Nesthus do not correlate to a real-world depressurization scenario...as that was not the purpose of the study. Are you certain that you meant to reference Nesthus, or could you be referring to a different study?" (#196). This was meant to expand the discussion so that the expert could enlighten me, as I was clearly missing something. Specifically, an answer to my question would have helped me to understand the arguments made, and perhaps have resolved some disagreement among other members. But as sometimes happens, my question went unanswered and nothing was learned. Oh, and I don't actually think I can fly an airplane, but I have fun trying, at least until the bills come in.
Right on!
I've said several times that it appears that the crew immediately executed an emergency descent.
Plus at least one person who has been all of the above depending on the day. (Hi, that's me.)
What's not funny is us layman are recognizing not coherent posts in relationship to the King Air occurrence. Please read all of the posts. Dr. Chien has an impressive CV and it appears he has helped many in his role as an AME but I don't see his expertise in physiology of hypoxia. He does have a valid point about unpressurized flight below 15000 and the political influence on that rule but recalls the details of the Nesthus report in error. Few, except one I can remember, of his posts address a pressurized crew losing pressure and putting masks on. In that one post he does address and claims to not know if the KA crew had appropriate masks for losing pressure at 350 or 250 and so we don't know their status. I think we all know their status even if it took 45 seconds to get the mask on. I have no problem with the KA crew deciding to let Garmin do it. I have a slight problem with them not taking over to land after the ED was complete. I also have a problem with no coms from them. My problem might also be because they might, I emphasize might, not have been trained, not studied the systems on the bird they were flying.
Unless they’ve changed it in the last 15 years, the King Air 200 AFM procedure for decompression includes an emergency descent, so I’m not sure how that’s evidence of, or even suggesting that, they followed the procedure in the Supplement.I've said several times that it appears that the crew immediately executed an emergency descent.
