MauleSkinner
Touchdown! Greaser!
And as we all know, simulators do a good job of replicating the effects of a decompression.
Autoland King Air 200 Due to Pilot Incapacitation Broomfield, CO 12/20/25
- Thread starter Kenny Phillips
- Start date
Last rapid D I know of is SW1380 at 320, compounded with an engine failure. Crew took their masks off leaving 10 and accomplished a single engine landing. The SW EP in the docket says crew must use O2 after level off if above 10 and switch to normal. Have you been recommended to stay on 100% after 10 all the way to the airport?
bbchien
Touchdown! Greaser!
Look up the article. Nestus, TR. et al. It's got ~40 pages. I'm not going to do your homework for you, e.g, unbind my copy, scan and attempt to post it. LOOK IT UP. I've posted the COVER page.
And it's not in the op manuals because nobody records how long the hypoxic insult is, at 18,000 or at 36,999. You might be okay but if your exposure was over a certain length (only data point known to be 30 mins at 12,500) you may NOT be okay....and for some minutes to come.
You might recall that the supplemental O2 rules a 12,500 and 14,000 feet were not based on science. They were based on political protest from the Colorado Pilots Assn. The data a much less forgiving than the regs.
midwestpa24
Final Approach
I can tell you from personal experience, if you wear a pulseox above even 8,000 feet, I think you'd be shocked at the result. Spend a full day flying at 8,000, and you can feel it.
I couldn't find it because the name is not Nestus. For those interested it can be found here: https://www.faa.gov/sites/faa.gov/f...arch/med_humanfacs/oamtechreports/AM97-09.pdf
But I don't see forebrain insult mentioned in the tome. With rapid donning of masks at the flight levels I don't know if you could say there would be an effect and Tammie Jo certainly handled a compound emergency well after taking her mask off leaving 10. I don't doubt going without O2 at 12500 would do something to you. When we climbed the cabin up to about 12000 to land at LaPaz the colors became brighter when we put the mask on. But the King Air pilots probably had O2 from event down to wherever they took the masks off. The premise that they had an insult at 18000 and would not have been right below 10000 I can't buy.
bbchien
Touchdown! Greaser!
Jim you missed that the group of pilots who were at 12.5 for 30 mintues continued to make errors siginificanly for commonly (.03) all the way down to landing 30 minutes later. That's the finding relevant to this discussion. And these were young pilots.
Now if the insult were at 350 mBar (far worse than 700 mBar) how might you possibly expect to exclude the probability that there is a lingering insult.....Deniers deny data that does not support their point of view.
Now if the insult were at 350 mBar (far worse than 700 mBar) how might you possibly expect to exclude the probability that there is a lingering insult.....Deniers deny data that does not support their point of view.
They need to relate that to 35000 for 15 seconds or 18000 and whatever it took the King Air crew to don. And then O2 at most likely higher than normal concentration and pressure in the descent. Can't remember what those regulators did. The report has general aviation pilots descending and recovering O2 partial pressure at existing altitude pressures, not from an O2 regulator.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,774
- Display Name
- DISPLAY NAME
This paper doesn't support the claims you made in this thread at all.
Cap'n Jack
Final Approach
It does.
MauleSkinner
Touchdown! Greaser!
According to the NTSB summary, it took Tammy Jo about two minutes to figure out memory item #2.
But I’m sure she was fully recovered by 10.
Lindberg
Final Approach
Here's the relevant claim, that these pilots, who immediately got their masks on, may not have recovered from hypoxia by the time they landed:
"So by inference, with 30 minutes of flight remaining, from Red Table at 18K.....they might not have been recovered. The Exact interval at 18,000 has not been established."
The study applied to pilots who were breathing hypoxic air for thirty minutes. There's no dispute that these pilots were immediately breathing oxygen. Maybe there's other data that supports the claim, but not this study, which tells us nothing about pilots who breathe hypoxic air for only seconds.
Read the whole report including the NTSB conclusions. I think the 2 minutes included some problems getting coms straightened out which is weak point. The Alaska crew had a problem with that after took their masks off. But if the SW crew had an insult and was a little slow at first, breathing O2 on the way down cleared it. The Nestrus report has the pilots get deprived at 12500 and only ambient air to breath on the way down. But again, what do your recommenders advise after 10000 on the way down, 100% or normal?
Presumably, way before the VASA video begins, since the first message is a comment from BJC tower saying that they've got an emergency inbound, so they had gotten an indication before the first transmission recorded. LiveATC only records what the streaming receiver can hear.
Nestus is the first author and a common way of referring to scientific papers.
Here's the TL;DR conclusion for those who aren't going to slog thorugh the math:
In summary, this study did not provide unequivo- cal evidence of detrimental flight performance due to the mild hypoxia found during the cruise segments at 8,000, 10,000, and 12,500 ft. simulated altitudes. However, observed performance during the descent and approach phases of flight was considered to be generally unsafe with potentially deleterious outcomes.
MauleSkinner
Touchdown! Greaser!
That would be memory item #2.
You’re sure it was 100% cleared by 10k?
Again,
Roger Wilco
Line Up and Wait
What a strange thread.
The real (and to me very interesting) story is that a GA autopilot system with this capability not only exists, but actually works as advertised. The pilots of the incident airplane chose to allow the automation to do its thing, resulting in a safe landing. Uncontroversial, and awesome.
As for O2 use in a cabin depressurization, an actual cabin depressurization event is different from flying a 172 from Phoenix to Gallup. Consider a scenario in which an aircraft at F390 experiences a rapid depressurization. I’ll stipulate that the cabin altitude increases at 300fps—a rather dramatic case—and that the cabin altitude is 11k when the crew identifies the problem. The event might unfold as follows:
Cabin altitude exceeds 10k; warning activates; crew recognizes warning; crew establishes/maintains aircraft control and desired flightpath; crew confirms cabin pressure loss; crew dons O2 masks…
The preceding should require 15-30 seconds to accomplish. During that time, cabin altitude would increase to 15.5k-20k and the crew would be breathing air at ambient pressure for 30 seconds or less.
Once O2 masks are on and supplying pressure-regulated 100% O2, the crew’s lungs are filled with 90+% O2 at a partial pressure significantly higher than ambient. Meanwhile, the crew executes procedures for the loss of cabin pressure and emergency descent. Once the aircraft descends to 10k or below, the crew may remove their O2 masks, but doing so is not required by procedure.
At this point, the crew’s direct exposure to cabin altitudes greater than 10k has been relatively brief and their O2 equipment has supplied them with a pressurized flow of 100% O2 for a period of 6-7 minutes, as required to descend (longer if an intermediate level-off occurred). Considering the preceding, the conclusions drawn from the study previously cited seems to be of little relevance, as that study is based on an entirely different set of scenarios.
My personal experience: crews performing simulated cabin depressurization/emergency descent events are quick to remove their masks reaching 10k, primarily due to the communications challenges the masks impose. My experience further suggests that, at and below 10k, difficulty in communicating creates a greater threat than any potential hypoxic effects of flight at those altitudes. But my experience is limited to simulated events; in the real-world each crewmember has to make his/her own determination as to whether additional O2 is required. It’s worth adding that when diversion circumstances and fuel state allow, crews should consider lower cruise altitudes.
But again, I think the real story is that a new magic exists, one that has actual potential to save lives. Cool.
The real (and to me very interesting) story is that a GA autopilot system with this capability not only exists, but actually works as advertised. The pilots of the incident airplane chose to allow the automation to do its thing, resulting in a safe landing. Uncontroversial, and awesome.
As for O2 use in a cabin depressurization, an actual cabin depressurization event is different from flying a 172 from Phoenix to Gallup. Consider a scenario in which an aircraft at F390 experiences a rapid depressurization. I’ll stipulate that the cabin altitude increases at 300fps—a rather dramatic case—and that the cabin altitude is 11k when the crew identifies the problem. The event might unfold as follows:
Cabin altitude exceeds 10k; warning activates; crew recognizes warning; crew establishes/maintains aircraft control and desired flightpath; crew confirms cabin pressure loss; crew dons O2 masks…
The preceding should require 15-30 seconds to accomplish. During that time, cabin altitude would increase to 15.5k-20k and the crew would be breathing air at ambient pressure for 30 seconds or less.
Once O2 masks are on and supplying pressure-regulated 100% O2, the crew’s lungs are filled with 90+% O2 at a partial pressure significantly higher than ambient. Meanwhile, the crew executes procedures for the loss of cabin pressure and emergency descent. Once the aircraft descends to 10k or below, the crew may remove their O2 masks, but doing so is not required by procedure.
At this point, the crew’s direct exposure to cabin altitudes greater than 10k has been relatively brief and their O2 equipment has supplied them with a pressurized flow of 100% O2 for a period of 6-7 minutes, as required to descend (longer if an intermediate level-off occurred). Considering the preceding, the conclusions drawn from the study previously cited seems to be of little relevance, as that study is based on an entirely different set of scenarios.
My personal experience: crews performing simulated cabin depressurization/emergency descent events are quick to remove their masks reaching 10k, primarily due to the communications challenges the masks impose. My experience further suggests that, at and below 10k, difficulty in communicating creates a greater threat than any potential hypoxic effects of flight at those altitudes. But my experience is limited to simulated events; in the real-world each crewmember has to make his/her own determination as to whether additional O2 is required. It’s worth adding that when diversion circumstances and fuel state allow, crews should consider lower cruise altitudes.
But again, I think the real story is that a new magic exists, one that has actual potential to save lives. Cool.
Indeed. This is a great demonstration. A lot of people pooh pooh this achievement in the same way the deride the Cirrus parachute, or in my other hobby, the flesh-sensing table saw feature of the SAWSTOP. Yeah, some top notch airmanship might obviate the need for these things, but it's often not operator-stupidity that leads into these situations.
Coming into BJC from the west, you have a very short distance to go from where being below 10,000 is a good idea. The terrain hits 9000' less than 7 miles from the airport.
Flying Keys
Cleared for Takeoff
- Joined
- Jul 2, 2021
- Messages
- 1,027
- Display Name
- Flying Keys
Rough timeline from data (times and positions are approximate):
2043z - N479BR departs ASE, flies the departure NW bound and turns ESE while climbing.
2052z - N479BR is on a 110°(T) track, climbing through 23,000’ when the climb reverses into a 4-5k FPM descending left turn to 18,000 and a course of 032°(T). During this sequence, the autopilot LNAV mode disappears from the ADS-B data, but AP master remains active. Alt hold is activated as it levels off at 18,000’.
2057z - N479BR squawks 7700 a mile south of Avon, CO and soon after turns right to a course of around 077°(T) (this is fairly close to direct BJC), still at 18,000’. Immediately after it establishes on the new inbound course, LNAV and VNAV are activated.
2100z - N479BR passes the Gore Range just NE of Vail, which has peaks over 13.5k. Altitude and track unchanged. There are still several ~13.5k peaks within 2nm of the course over the next 20nm.
2109z - N479BR begins a 1500-2000FPM descent from 18,000’ to establish an approach into BJC. This descent begins about 5-7nm after passing the last 10,000+ foot peaks within 1-3nm of the course. The aircraft is about 8nm from BJC at this point.
2110z - (about a minute later) is presumably when we hear the first automated transmission from N479BR on BJC’s tower frequency (in VAS’s video), based on the “two miles south” position report and the timestamp of the track that matches that. The aircraft is descending through around 15.5k’ at this point and turning onto a downwind.
2114z - N479BR descends through 10,000’ while maneuvering toward an approach.
2119z - after completing a “box” 360 and some more maneuvering onto the approach, N479BR safely lands at BJC
It is if you use the correct spelling which we all have not been doing. Nesthus.
No, but I'm sure they were not "not right" and per NTSB:
"Performing required checklists according to standard operating procedures is a critical part of safe flight operations. However, given the emergency situation aboard this flight, the flight crew’s performance of most, but not all, of the items on the Engine Fire or Engine Severe Damage or Separation non-normal checklist and the nonperformance of the three other relevant non-normal checklists allowed the crew to appropriately balance the procedural requirement of executing checklists with the high workload associated with maintaining airplane control and accomplishing a safe and timely descent and landing."
In the past and based on what I glean now, airline crews can and will take their masks off at 10 if they feel "right". The NTSB did not add a recommendation in the SW report that advises against what the crew did. Perhaps our AME, @bbchien can find a more pertinent report that involves cabin pressure, mask delay, time of 100% O2, and remaining degradation. I do remember a story from an AF cargo pilot where the decompression was immediate and my memory is hazy but they were not right for some time.
I don't doubt that you heard to keep O2 100% to the ambulance but I haven't heard that not that I wouldn't do it if I felt the need.
MauleSkinner
Touchdown! Greaser!
Seems to me that determining one’s own level of impairment after a depressurization event would be similar to determining one’s own level of impairment based on how you feel at the moment after having a few drinks or when being sleep deprived, neither of which are generally accurate.
Until you and @bbchien convince the FAA and airlines to require us to keep O2 100% to the gate that judgement is what we have to do at 10000.
MauleSkinner
Touchdown! Greaser!
Good thing I avoid airlines if the pilots are required to be that self-unaware.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,774
- Display Name
- DISPLAY NAME
Where?
flyingcheesehead
Taxi to Parking
- Joined
- Feb 23, 2005
- Messages
- 28,191
- Location
- UQACY, WI
- Display Name
- iMooniac
- Home Airfield
- KUES/KMKE
Strange, yet strangely predictable, based on what I remember the community's reaction to the LVL button and the BRS chute was back in the day.
Absolutely.
Do you suppose that when Lawrence Sperry invented the autopilot back in 1912 that the Wright Brothers talked **** about it and said that real pilots wouldn't use it? Or does that sort of idiocy require the Internet?
- Joined
- Jul 3, 2011
- Messages
- 5,482
- Location
- GDK & SBS
- Display Name
- Geezer
- Home Airfield
- GDK Greene County
Some of the comments in this thread reminds me of the absence of parachutes in the AEF Flying Squadrons in WWI.
“ American pilots never wore them because the higher ups—who had never flown themselves before—believed that these devices would make a pilot likely to jump out at the first hint of danger. Too many planes would be lost.“
www.thehistoryreader.com
“ American pilots never wore them because the higher ups—who had never flown themselves before—believed that these devices would make a pilot likely to jump out at the first hint of danger. Too many planes would be lost.“
Why Pilots Didn't Wear Parachutes during World War 1 - The History Reader : The History Reader
Why weren't American pilots issued parachutes in World War 1? John F. Ross discusses the reasons for this and the harrowing choice faced by the pilots.
www.thehistoryreader.com
hindsight2020
Final Approach
Glad you said, "some" comments. Don't lump us all in that camp. Some of us are merely highlighting the slippery slope of employer risk compensation with the proliferation of that automation "vertical integration". That isn't the same as making a Luddite argument. I certainly recognize there is no retirement/longevity-sustaining future in the piloting occupation in the 21st century. Certainly not one with the current levels of major airline pay, latter which is largely what motivates most who enter as opposed to staying in whatever desk they ran away from. Everything comes to an end.
The sunsetting of the pilot occupation needs to be done carefully. There's too much risk in allowing impostors and the atrophied to hide behind the automation just to gain access to a dying seat at lower pay, especially at non-CBA firms. We saw this in the early 2000s, though through a slightly different mechanism. Bystanders died for it.
The sunsetting of the pilot occupation needs to be done carefully. There's too much risk in allowing impostors and the atrophied to hide behind the automation just to gain access to a dying seat at lower pay, especially at non-CBA firms. We saw this in the early 2000s, though through a slightly different mechanism. Bystanders died for it.
Last edited:
bbchien
Touchdown! Greaser!
Correct. But you cannot determine that they "WERE right" and so haow are you going to hold to task (be critical) of a KA crew that decided to watch it automate itself down.....
You are not understanding the argument. Nobody is taling about 100% down to the ambulance, just that 12,500 is not a recovery -from a frontal lobe hypoxia altitude. Per Nesthus! There isn't any other science. But he did establish that one does not recover immediately when the oxygen is put in place.....and that was at 18,000. The recovery was still not complete in the 12,500 foot insult. This was from 18,000......
The 12,500 and 14,000 foot rules were not based on science. But maybe you only get ops checklists.....which is okay too. Soemtimes it's nice to understand the science, too. Or is Science a hoax?
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,774
- Display Name
- DISPLAY NAME
Please, just stop. You can't accuse someone of not understanding an argument when you're inappropriately citing a source that does not claim what you say it claims. Your understanding of the Nesthus study is worse than an AI hallucination.
Last edited:
I'm critical of the KA crew for not communicating and I'm wondering what they did for 45 seconds. Others are critical of them using the automation and defenders of the KA crew are citing O2 concerns. I then questioned some of the statements about hypoxia.
Roger Wilco
Line Up and Wait
That may have transpired before I was active here.
Well, Larry Sperry later told me that he invented it just to impress girls. But while the Wrights, Curtiss, and Sperry were bickering amongst themselves, Lincoln Beachey was the one who was out and about, gallantly debauching the jeunes femmes.
Aviation has an odd cohort of specimens that constantly gripe about the status quo, but when something new comes along they immediately leap into their foxholes and start tossing grenades. Seems like it's been that way since at least the late 1970s when I started flying. At least the Internet makes it easy to ignore them. But then again, I too am just SRGOTI.
whitepines
Pre-Flight
- Joined
- Aug 21, 2020
- Messages
- 79
- Display Name
- whitepines
I think deep down we are all afraid of the day when mankind finally loses our recently gained privilege of flight to a machine of one sort or another. Any technical advancement that doesn't also increase required pilot skill moves us inexorably closer to that day, hence the understandable hostility.
Just my $0.02 from SGOTI that would very much miss looking at the clouds from above, in control of a machine that would have been considered sci-fi fantasy just over 100 years ago.
bbchien
Touchdown! Greaser!
So just what part of it took them 30 minutes (making errors 30 minutes later, on sea level approach) after a 12,500 30 minute exposure, and the young pilots were still getting it wrong....to tell you that at 18,000 you put the mask on and you're immediately okay at 10,000?
I've met enough "science is a hoax-ers" for this week.
Last edited:
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,774
- Display Name
- DISPLAY NAME
That's not what the study says, you have been literally making up whatever you want to fit your argument.
Unfortunately, we've reached the point it is safe to assume anyone whose argument devolves to "believe the science" is probably a straight up liar.
Roger Wilco
Line Up and Wait
As much as I hate to get into the middle of this, I did download Nesthus and read through it, and what I read does not coincide with what you have posted.
The stated purpose of the study was expressed thusly: "The study was designed to evaluate complex pilot performance during simulated flight because comparatively less research has been conducted on hypoxia in a flight simulation environment." To amplify my comment in #176, the purpose, methodology, procedures, findings, and conclusions published in Nesthus do not correlate to a real-world depressurization scenario such as the example I provided, 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?
Roger Wilco
Line Up and Wait
Eloquently put. My perspective is different and I will try to be succinct.
We employ new technological advances in order to make flying safer, more efficient (profitable), and other practical purposes. We also employ new technologies that can increase pilot skills and performance. By this, I do not mean the stick-and-rudder skills that I believe you are referring to, but the skills nessary to operate the machine in the current environment. This has been the trend for quite some time, and the effects show up in several successive generations of pilots. As much as I tend to be defensive about my (former) profession, I freely admit that a sobering number of airline pilots hired after the mid-1990s struggle to hand-fly without the aid of a flight director and FMC-generated guidance. However, I must also admit that the occurrence of accidents and serious incidents has never been lower. However we choose to measure piloting skill, these aviators are doing a great job of getting airplanes from A to B without crashing, which is what customers, airlines, stockholders, and government agencies, want.
But that's commercial aviation. For pilots such as you and I who cherish the "privilege of flight in a machine of one sort or another;" who value the stick-and-rudder skills that we were taught; who delight in guiding our craft through three-dimensional space with smothness and precision; who strive for perfection while humbly recognizing and respecting our limits; and who find personal meaning and fulfillment in all of this: for us the answer was never found in the machines of yesterday's sci-fi fantasy, but in the actual machines of yesterday themselves. A 747 was designed to transport a 100,000 lb payload 7000nm at 86% of the speed of sound, but a J-3 Cub was designed to fly.
bbchien
Touchdown! Greaser!
So if you're impaired for 30 mins after 30 mins of 12.5k exposure, you’re supposed to be okay by coming down to 12.5 k from 18 immediately?….that makes very little sense.
And note: in the pressure protocols they were not "ramped down to sea level". They turn the valve and restored sea level pressure at the 30 minute mark- so it is as if the were on sea level oxyen right at the end of the 30 minute exposure to 12,500 (like wearing oxygen).
The point all are missing is that putting oxygen on immediately , even only from 12.5, didn't fix the error making of the third group over the next 30 minutes, and that was from 12.5, not from FL18. FL 18 can't be better, it's got to be worse.
Remember, the Nesthus kids were a mean 23 y.o. The pilots of the king air- much older.
And note: in the pressure protocols they were not "ramped down to sea level". They turn the valve and restored sea level pressure at the 30 minute mark- so it is as if the were on sea level oxyen right at the end of the 30 minute exposure to 12,500 (like wearing oxygen).
The point all are missing is that putting oxygen on immediately , even only from 12.5, didn't fix the error making of the third group over the next 30 minutes, and that was from 12.5, not from FL18. FL 18 can't be better, it's got to be worse.
Remember, the Nesthus kids were a mean 23 y.o. The pilots of the king air- much older.
Last edited:
The study I found and linked used 4 O2 mixtures to simulate the 21% O2 partial pressure at the 4 altitudes. Studies show that's a valid way to do it without a chamber. But where do you get 30 minutes. I see 45 minutes and then they do not explain how they increased the simulated O2 partial pressure on the descent. They had 4 preset mixtures so the subjects breathed 12.2 then 10.0 then 8 then S.L. And I don't see the descent time. The KA crew presumably had 18000 cabin altitude exposure for about 15 seconds. I don't know what system they had but most likely they then were on 100% O2, maybe even under slight pressure. Nesthus does not apply. And does not apply when we lose pressure at 30 and above and use masks on the way down to 10.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,774
- Display Name
- DISPLAY NAME
No, breathing ambient sea level air after being hypoxic for 30 minutes is not like breathing 100% oxygen in a pressure demand mask after being hypoxic for a few seconds. A scientist would not apply data from one scenario to a completely different scenario. Your assertions are utterly unscientific.