Home made O2 systems, AOPA article

[Sig600]

Anyone else read the article in this months AOPA about the Baron pilot killed by hypoxia? Was using a home brewed O2 system, and it got me thinking to the posts I've read on here, guys touting their use of home made systems. I never gave it a second thought until I read the article (sounds like a great idea for cruising high!!!). It goes into what exactly he used to build his system, and I realized just how complicated a true aviation O2 system is.

High altitude and hypoxia recognition training saved my life a while back at FL480, so be careful out there. This is one of those lessons we seem to keep learning over and over again in aviation. You only get once chance to screw it up.

As another learning point, I remember doing a basic demonstration in the altitude chamber back in basic. They tuned off the lights except one red light on the roof, and took us to 10,000. I didn't think much of it, as I used to fly a couple of light twins around between 12 and 15 all the time without O2 (yes I'm admitting that). After 15 minutes or so, they had us put our mask on and take a few breaths. After three breaths I seriously thought someone had turned the lights on. I never picked up on my vision degredation, and the results were scarey, at just 10K.

[PCHunt]

Link to article? Or magazine date? Thanks,

[rocketbob]

I read it. He was using a non-adjustable regulator AND he was using cannulas above 18K. Even if the regulator is non-altitude compensating, that's ok if you know the flow with flowmeters in series with the breathing apparatus in conjunction with a pulse oxymeter.

[Sig600]

Originally Posted by rocketbob

I read it. He was using a non-adjustable regulator AND he was using cannulas above 18K. Even if the regulator is non-altitude compensating, that's ok if you know the flow with flowmeters in series with the breathing apparatus in conjunction with a pulse oxymeter.

He was found, still strapped into the seat, waring a mask. Pulse oxymeter was found in the wreckage, and he kept very detailed logs, and a journal.

The NTSB found the pilot strapped in the left front seat and wearing an oxygen mask.

Link to the article.

http://www.aopa.org/asf/asfarticles/2011/sp0211.html

Regardless of what he had DONE, at the time he was doing everything right... minus using a homebrewed system. The hypoxia was slow, and he never recognized it.

[rocketbob]

Oh ok I missed that part, but it did mention that he wore cannulas above 18K because it was more comfortable. What it did say however, is he ran out of oxygen. Without an adjustable regulator and some sort of oxymizer in place no matter what, the bottle's gonna run out at some point, most people here are putting systems together that are efficient.

[airguy]

Originally Posted by rocketbob

What it did say however, is he ran out of oxygen.

Just like fuel. Ya gotta keep the quantity sufficient for the usage, no excuses. People still run perfectly good airplanes into the dirt on a regular basis because they neglected to monitor fuel supply, you can't fix stupid.

[az_gila]

At 27,000 ft there is not much time to observe and make corrections to the O2 system...

He was a little higher than this...

Height: 8000m

Faculty Effect
Visual Skills Loss of consciousness in approx 4 minutes
Memory Loss of consciousness in approx 4 minutes
Reaction / Motor Skills Considerable confusion in approx 2.5 minutes
Personality Change Loss of consciousness in approx 4 minutes
Perception Often none until consciousness lost. Otherwise as above

From here -

http://www.altitudecentre.com/mounta...ng/hypoxia.htm

This parachute link puts it a a little less time...

http://www.koyn.com/CloudDancer/articles/23KJump99.html

"The time of useful consciousness without supplemental oxygen at 23,000 is approximately 4 minutes."

Not much margin at those altitudes.

ADDED

At the heights we would normally be at, loss of conciousness is unlikely - still bad though...

Height: 6000m (about 19,000 ft)

Faculty Effect
Visual Skills Tunnelling of vision and more loss of colour perception
Memory Profound short term memory impairment
Reaction / Motor Skills Profound generalised reaction time slowing and error rate increase. Clumsy movements. Small chance of fits and loss of consciousness
Personality Change Frequent personality change. Volatility, judgement and insight impairment. Considerable disinhibition & loss of willpower
Perception Frequently none. Very obvious to others. Feeling drunk, unreal confused, uncoordinated “tingling pins & needles"

[PCHunt]

From the report:

The pilot kept an electronic journal where he wrote, according to the NTSB, ?He would attempt to fly high in an effort to get more efficiency from the engines, and would use the oximeter to monitor his blood oxygen levels. He stated that below 80-percent oxygen saturation, ?I notice a degradation of my cognitive ability.?

If you are using a pulse oximeter, anything below 90% should be cause for alarm, and take immediate action to correct the situation.

[Av8torTom]

80% O2 saturation is SERIOUSLY low. You get below 90% in a hospital, and they'll be oiling the wheels on the crash cart...

[RV6_flyer]

Originally Posted by PCHunt

From the report:

The pilot kept an electronic journal where he wrote, according to the NTSB, He stated that below 80-percent oxygen saturation, ?I notice a degradation of my cognitive ability.?

If you are using a pulse oximeter, anything below 90% should be cause for alarm, and take immediate action to correct the situation.

Having used O2 in my RV-6 for the past 13-years, I agree that anything below 90% does adversely effect your piloting skills. You need to increase O2 flow or descend.