Oxygen toxicity

[BiffF15]

The FAA Rules require that the pilots already be on oxygen while above 35,000ft (41,000 if quick-don masks are available and two crew are at the controls).

The chaos in the back is secondary

We have the quick don on 100% of our A/C.

 

[davparlr]

The FAA Rules require that the pilots already be on oxygen while above 35,000ft (41,000 if quick-don masks are available and two crew are at the controls).

Similar to what we had back in the '70s

The chaos in the back is secondary

Not if the second step in your checklist is "Crew Communications - Establish", and communications cannot be quickly established due to chaos. How long does the pilot wait before descending? Incapacitation time is only a matter of seconds at very high altitudes.

 

[davparlr]

We have the quick don on 100% of our A/C.

Davparlr,

The checklist, and checklists at my airline are well vetted. When we do normal training or check rides if a checklist is disliked or misinterpreted there is a focus put on it. Also the changing of said checklists is a well known process.

At least in the Air Force, difficult to do. In the C-141, if the anti-lock brakes were not available, 3000 ft (iirc) was required to be added to the stopping distance for takeoff calculations, particularly go speed, the speed which once obtained the plane cannot stop on remaining runway. The anti-lock brakes are on the No. 2 hydraulic system. I wanted a caution note placed in the dash one that, if No. 2 hydraulic fails on take off, go speed will be much slower. Alas, to no avail, it was dismissed.

You are also assuming a rather large hole has appeared. Most of the time it's the outflow valve failing.

I would rather plan that it could happen rather than assuming it will not.

When flying in high terrain, or ground level at or above 10k we build escape routes into the navigation system (off route) and is published by Jeppensen. These routes are designed to get down to 10k ASAP.

Alas, we had no such support. All we had was a navigator, which maybe good, or not. There was one incidence of a C-141 about to penetrate the ADIZ about 300 mile north of course. The pilot caught it when he listen to and deciphered the VOR (who does that), which ironically, had the same frequency as the correct one to the south, identified the error in time to report it. Getting joined by a pair of 106s who want to fly formation with you is not career enhancing. We did lose two planes to terrain problems, one was slightly off course and ran into a mountain in South America, at 18,000 ft. The wreckage was not recovered, the other occurred in Spain when the crew was instructed to descend to 5k, he read back 3k, The controller did not catch the error and instructed the pilot to contact approach control, in doing so he reported he was descending to 3k. The controller said standby we have an emergency in progress. He impacted a mesa at 3800 ft.

 

[The Basket]

35000 ft?
What about 34999 ft?

10,000ft is borderline so that's pretty low in comparison.

 

[Zipper730]

From what I remember, the basic rules of aviation are

1. Aviate: Keep the plane flying at all costs. I reason that if you lose consciousness, the rest becomes kind of irrelevant.
2. Navigate: Make the plane go where you want it to
3. Communicate: Tell everybody what's going on

 

[Koopernic]

My limited human physiology training says the opposite occurs, pbehn. It's an increasing PaCO2 that will produce a higher respiratory rate and depth.
Subjects here are breathing air or air containing 2%, 4% or 6% CO2....

View attachment 613929

I did a SCUBA course decades ago. We were warned not to hyperventilate prior to snorkeling as this would purge the blood of CO2. It is the presence of CO2 rather than the absence of oxygen that triggers the urge to breath. Divers have blacked out and died from hypoxia and drowning because prior hyperventilating had removed the natural CO2 balance from the body and they did not have the urge to breath. A good snorkeler can easily stay down 4 minutes. It's a matter of staying calm and mindful rather than hyperventilating. They are extremely graceful to watch and do not surface breathless.

It is known that premature babies left in oxygenated humidicribs can suffer damage over a long period from oxygen.

 

[Koopernic]

35000 ft?
What about 34999 ft?

10,000ft is borderline so that's pretty low in comparison.

There are indigenous people that live at nearly this altitude, I immagine they can handle this due to acclimatization and greater amounts of blood.

I work in the mining industry. I have colleagues that work at that altitude. Lithium and gold mines in the Andes. They sleep with an oxygen bottle at hand, lots of medicals to get on site. Work is done in 15 minute batches with rest and job planning breaks in between.

On another note: I think Me 163 pilots breathed oxygen before takeoff in part to lower N2 in the blood to avoid the bends.

 

[pbehn]

There are indigenous people that live at nearly this altitude, I immagine they can handle this due to acclimatization and greater amounts of blood.

I work in the mining industry. I have colleagues that work at that altitude. Lithium and gold mines in the Andes. They sleep with an oxygen bottle at hand, lots of medicals to get on site. Work is done in 15 minute batches with rest and job planning breaks in between.

On another note: I think Me 163 pilots breathed oxygen before takeoff in part to lower N2 in the blood to avoid the bends.

I saw a holiday programme about trips to the Andes. Obviously for those who live there natural selection made it possible over the years. For those who visit there are procedures to acclimatise but some just cant, it is nothing to do with fitness.