Safest, most redundant oxygen setup for single pilot or dual occupant in the FL's?

[Marc_B]

19 minutes ago, EricJ said:

So what were your symptoms? 

I've done the PROTE twice, and my symptoms are 1) faint skin tingling, 2) a slight feeling of breathless or needing to breathe deeper, and 3) an "overtired" feeling (similar to pulling an all nighter) that I guess is best described as feeling a little dull--not as "sharp."  Both times it took over 5 minutes to drop down to 68/69% SPO2.  Both times I felt that this was "off" but I don't think that I ever stayed in to the point of complete dysfunction.  One of the questions they asked me around 4 mins in was to count backwards from 100 by 7's...this takes attention for me even with a cup of coffee and a full nights sleep! I made it about 4-5 seven's down and misspoke but recognized "60" wasn't right.  They had me write "60" on my page.

Speaking with the FAA PROTE staff they want pilots to go back on oxygen if you have 3 symptoms, at 5 minutes, or if you get below 65%.  This way you hopefully won't have hypoxia amnesia and will remember the symptoms you had and the experience.  If you go too low you just won't remember and can't learn from it.

As an indirect marker, it's interesting that my HR increases 20-30 bpm with even mild hypoxia.  So a clue that something is off isn't just lower SPO2, if I notice that my HR is much higher than my baseline that would be a something important to pay attention to!

It is just as interesting to see others do this and see the variety of how pulse ox readings plunge or don't.  One of the older gentlemen in the group stayed in the mid 70's past 5 minutes, but clearly had issues putting shaped toys into the right shaped hole.  So SPO2 number isn't everything.  I also saw a young, fit guy who dropped like a rock and his SPO2 was in the 60's two minutes in.

Physiologically there are two drivers to stimulate breathing: high CO2, and low SPO2.  People have different responses to those stimuli in addition to having different adaptations / ability to tolerate them.  i.e. think of a free diver who can tolerate much higher CO2 levels without the panic need for a breath; or think of a Sherpa who lives at Everest base camp year round.

I'd highly recommend a PROTE experience every year or two!!

[Pinecone]

17 hours ago, BlueSky247 said:

So from a flight ops perspective, what is the safest descent rate we could automate and how would you configure mp/power levels? Or is that something a decent AP would have safeguards built in for? (This is assuming we are at risk for passing out and want to use the AP as a safety net.)

As long as you do not exceed Vne and do not descend too low, you can pick any combo.

If you want to get down NOW, set a IAS descent, power to idle, prop full forward, gear down.  Speed brakes deployed if you have them.

But at the altitudes we fly, you are not going to die from descending too slowly.  But the sooner you get lower, the sooner you will wake up.

[BlueSky247]

@Pinecone Much appreciated! I hear so much about avoiding shock cooling and was thinking just dropping to idle would be no bueno.  But yea, we're talking an emergency situation, not best treatment of the engine for long term lifespan. 

 

 

[N201MKTurbo]

The quickest way to get down in an emergency is still the commercial spiral. Power to idle, slow down to flap speed, throw everything out, flaps, gear speed brakes, do the tightest turn you dare while maintaining the max flap speed. You will come down at a few thousand FPM.

[Marc_B]

40 minutes ago, N201MKTurbo said:

The quickest way to get down in an emergency is still the commercial spiral. Power to idle, slow down to flap speed, throw everything out, flaps, gear speed brakes, do the tightest turn you dare while maintaining the max flap speed. You will come down at a few thousand FPM.

I'm conflicted on this one.  At the levels we fly at and the time durations we're talking about I think that a stable, AP descent would probably be the smartest in my mind.  Being hypoxic and disoriented and trying to do a spiral descent just seems a recipe for a rodeo ride.

My informal plan if I run into issues would be to set at least 10,000 feet (or lower--terrain dependent of course) into the Altitude Target Select, press VS for a vertical speed descent and aim for 800-1000 FPM.  This will safely keep me from overspeeding if I just keep my power settings same (I figure why add complexity), give me a tolerable descent rate but relatively quickly down to denser air. 

But most scenarios I come up with in my head regarding isolated Oxygen Emergency aren't "the sky is falling" emergencies, but rather I find myself hypoxic, something isn't working, I'm somehow disconnected, or I'm not exactly sure what the issue is but my pulse ox is lower than it should be.  Even in the PROTE at simulated FL270, we went from SL to 27,000 feet instantly and it wasn't the same urgency as an inflight fire and need to get down on ground ASAP (which is something I'd use the spiral descent for).

[Marc_B]

As an aside regarding commercial maneuvers:  My original POH listed two step by step descent flows (gear up 196kts vs gear down 165kts) for this, but subsequent revision of POH actually suggests a preference for gear down and only lists step by step for gear down.  I didn't find descending at VNE very confidence inspiring...it just felt like I'm doing something potentially dangerous.  But descending at 165kts seemed like I was MUCH more in control, smoother, and just as quick FPM descent.

"In the event an emergency descent from high altitude is required, rates of descent of at least 3,000 feet per minute can be obtained in two different configurations:(l) With landing gear and flaps retracted and cowl flap closed an airspeed of 196 KlAS will be required for maximum rate of descent.(2) With the landing gear extended, flaps retracted and cowl flap closed an airspeed of 165 KIAS will also give approximately the same rate of descent. At 165 KIAS and the gear extended, the angle of descent will be greater, thus resulting in less horizontal distance traveled than a descent at 196 KIAS. Additionally, a descent at 165 KlAS will provide a smoother ride and less pilot work load."

[N201MKTurbo]

26 minutes ago, Marc_B said:

I'm conflicted on this one.  At the levels we fly at and the time durations we're talking about I think that a stable, AP descent would probably be the smartest in my mind.  Being hypoxic and disoriented and trying to do a spiral descent just seems a recipe for a rodeo ride.

My informal plan if I run into issues would be to set at least 10,000 feet (or lower--terrain dependent of course) into the Altitude Target Select, press VS for a vertical speed descent and aim for 800-1000 FPM.  This will safely keep me from overspeeding if I just keep my power settings same (I figure why add complexity), give me a tolerable descent rate but relatively quickly down to denser air. 

But most scenarios I come up with in my head regarding isolated Oxygen Emergency aren't "the sky is falling" emergencies, but rather I find myself hypoxic, something isn't working, I'm somehow disconnected, or I'm not exactly sure what the issue is but my pulse ox is lower than it should be.  Even in the PROTE at simulated FL270, we went from SL to 27,000 feet instantly and it wasn't the same urgency as an inflight fire and need to get down on ground ASAP (which is something I'd use the spiral descent for).

I wasn’t suggesting that in an oxygen emergency. I is the fastest way to get down. In most cases, the first thing I would do is troubleshoot the situation and try to get the oxygen flowing again. 
 

The last time I did the emergency descent was my last flight review. I was flying along and the CFI reaches down and pulls the throttle to idle and says “your engine just quit” so I picked a spot and trimmed for glide and was just hanging out waiting to descend when she says “and you are on fire”, so out goes the gear and cranked it over hard. When we got down to about 500 feet she says “you got this, you can power up” and I said, “let’s see if I really do have this” so I glided down till I was in ground effects on this farm road and then powered  and went missed. In my log she listed a touch and go in the desert. I said I didn’t touch, she said I did. 

[MikeOH]

5 minutes ago, N201MKTurbo said:

I wasn’t suggesting that in an oxygen emergency. I is the fastest way to get down. In most cases, the first thing I would do is troubleshoot the situation and try to get the oxygen flowing again. 
 

The last time I did the emergency descent was my last flight review. I was flying along and the CFI reaches down and pulls the throttle to idle and says “your engine just quit” so I picked a spot and trimmed for glide and was just hanging out waiting to descend when she says “and you are on fire”, so out goes the gear and cranked it over hard. When we got down to about 500 feet she says “you got this, you can power up” and I said, “let’s see if I really do have this” so I glided down till I was in ground effects on this farm road and then powered  and went missed. In my log she listed a touch and go in the desert. I said I didn’t touch, she said I did. 

@N201MKTurbo

So, is that T&G still in your log, or not?

[Will.iam]

One of the articles a test pilot wrote about having an issue while certifying the 252 at FL280 was he was at cruise when his leg went numb, he dropped the gear and chopped the power and nosed over in a dive, the point is although your TAS is very high, 200+ mph your indicated is very low sub 120KIAS and since gear speed limitation is based on indicated not TAS you can drop the gear at cruise without slowing down. Once down now you can accelerate to 165 (for the 252) and that initial acceleration from sub 120 to 160ish especially up high in thin air gives impressive descent rates. Also you can pull to 20”mp and reduce RPM to 2200 and that will take alot of power away but still keep the air from driving the prop or shock cooling the cylinders for even more descent rate. 

[N201MKTurbo]

1 hour ago, MikeOH said:

@N201MKTurbo

So, is that T&G still in your log, or not?

That’s what she wrote in the log. The report she gave me listed all the landings separately. I would have to find that.

[Fly Boomer]

4 hours ago, N201MKTurbo said:

so out goes the gear and cranked it over hard

What was your bank angle and rate of descent?

[N201MKTurbo]

2 hours ago, Fly Boomer said:

What was your bank angle and rate of descent?

I was probably only doing 45 degrees. I’m not sure what the descent rate was. It pegged the VSI. I was mostly watching the ground and my landing spot. We started about 3500 AGL it took a minute or two to do the low pass on the road. I stopped the spiral and set up on base at about 500 feet.

[Scott Ashton]

If you are really concerned about an oxygen emergency, we have a one place emergency descent system that we produce for pressurized airplanes that gives between 20 and 40 minutes of oxygen in a reusable system.   We sell it for pressurized aircraft mostly but it would fit right in the seat back and give you a good reliable backup.  
Most of the failures I have heard about have been due to the user pulling the tube off the Flowmeter accidentally.    Search the ASRS reposts too.  I only found one incident and this is what it was.   
PM me and I will sent you a link or good PrO2.

scott

 

[M20F]

Anyone got details on how many non-pressurized GA planes crash due to hypoxia in the low flight levels?

[toto]

27 minutes ago, M20F said:

Anyone got details on how many non-pressurized GA planes crash due to hypoxia in the low flight levels?

Unfortunately I suspect the cause of many of those crashes is going to be speculative / undetermined.

[Pinecone]

On 8/2/2024 at 11:18 AM, N201MKTurbo said:

The quickest way to get down in an emergency is still the commercial spiral. Power to idle, slow down to flap speed, throw everything out, flaps, gear speed brakes, do the tightest turn you dare while maintaining the max flap speed. You will come down at a few thousand FPM.

Agreed, but not possible to set that up for the autopilot to fly if you pass out. 

I was addressing the situation of what can I setup that I can go to sleep and wake up alive. 

[Pinecone]

3 hours ago, M20F said:

Anyone got details on how many non-pressurized GA planes crash due to hypoxia in the low flight levels?

I would think that pressurized is more of a problem.   Thinking everything is OK, until too late.

We have had a number of those.

And we would know, as everything above 18,000 is IFR, so you are talking to someone, who will notice if you stop answering.

[Pinecone]

5 hours ago, Scott Ashton said:

If you are really concerned about an oxygen emergency, we have a one place emergency descent system that we produce for pressurized airplanes that gives between 20 and 40 minutes of oxygen in a reusable system.   We sell it for pressurized aircraft mostly but it would fit right in the seat back and give you a good reliable backup.  
Most of the failures I have heard about have been due to the user pulling the tube off the Flowmeter accidentally.    Search the ASRS reposts too.  I only found one incident and this is what it was.   
PM me and I will sent you a link or good PrO2.

scott

 

HI, we met at Sarasota Avionics fall 2022.

I looked at your page.  What is the difference between the PrO2-2 and the EMT-3-1

[Pinecone]

On 8/2/2024 at 10:06 AM, BlueSky247 said:

@Pinecone Much appreciated! I hear so much about avoiding shock cooling and was thinking just dropping to idle would be no bueno.  But yea, we're talking an emergency situation, not best treatment of the engine for long term lifespan. 

https://www.avweb.com/ownership/shock-cooling-time-to-kill-the-myth/

[BlueSky247]

@Pinecone Good to know! TYVM.

[exM20K]

4 hours ago, M20F said:

Anyone got details on how many non-pressurized GA planes crash due to hypoxia in the low flight levels?

I know of 2 in long body money aircraft

http://www.kathrynsreport.com/2012/03/mooney-m20m-n400de-what-happened-next.html

and the acclaim on the way to a MAPASF PPP in Atlantic City.

http://www.kathrynsreport.com/2017/10/mooney-m20tn-acclaim-n370mm-fatal.html

 

It happens. I limit myself to FL180 unless there is a compelling reason to go higher.

-dan

[exM20K]

26 minutes ago, Pinecone said:

 

And we would know, as everything above 18,000 is IFR, so you are talking to someone, who will notice if you stop answering.

And then you die.

-dan

[kortopates]

On the topic of steep idle descents, shock cooling is a myth but ring flutter is not! This is why both engine manufacturers talk about never doing a closed throttle descents but maintain a minimum amount of power of at least 15” to prevent the air from turning the prop rather than the engine turning the prop. Having the prop turn the engine reverses the stress on the rings and can damage them on a prolonged descent. The immediate symptom right after such damage will be much elevated oil consumption. Recall one pilot that did an emergency descent from flight levels to an airport below him with closed throttle and opted to overhaul soon thereafter. Of course depending on the nature of the emergency, the engine may be the least of your concerns.

Above though @Will.iam talks about the proper safe way to do an emergency descent without risking damage to the engine above.
But the other concern for engine management is don’t go to full power immediately if you go around, just use enough power to maintain level flight as oil temp and CHT comes back as you fly over the runway and by the departure end temps will be good off to go to high power.


Sent from my iPhone using Tapatalk

[Scott Ashton]

4 hours ago, Pinecone said:

HI, we met at Sarasota Avionics fall 2022.

I looked at your page.  What is the difference between the PrO2-2 and the EMT-3-1

Sure!   I remember!  The EMT has a switchable regulator so you can turn it on and off.  The PrO2's have an activation key that starts the flow and continues until empty in the event of a decompression event.  The PrO2 also comes with more options on cylidner size and number of users....

Coming back to FL any time soon?

Scott

[Danb]

On 7/31/2024 at 1:34 PM, N201MKTurbo said:

Keep one of these in the plane.

Great idea have two..