Bob,

 

I would like to see the proof that welder's O2 is any less viable than that available from the local FBO. BTW, my cockpit located O2 bottle will not fall below freezing while I'm inside.  OK, I do keep my plane in a heated hangar.  If there was water in welders O2, their regulator would also corrode, mess up the regulator and probably screw up the weld job, too.

 

Pulse Oximeters are worth your life.  Creeping hypoxia may not be self-recognizable.  The reading are reliable enough to set your own danger limit.  Mine reads 96% at 700 MSL and it is not allowed to go below 89% in flight.  Sensitivity to O2 absorption varies with age, weight, sleep, Density altitude, etc. and may vary from day to day.

 

  Recently, there was an article written about how deep breathing can indeed keep your O2 saturation level up - but, it required conscious effort and the saturation level dropped rapidly when the deep breathing ceased.. 

 

BTW, CO will also raise the reading of an Oximeter.  There should be a digital CO detector in the cockpit, too.

 

 

Hi Stuart,

 I’ve used welder’s oxygen in the past also.  It does cost about $10.00 a fill vs. aviation oxygen @ $80.00 for my last fill.  But, don’t do it, welder’s oxygen contains too much water, and other impurities.  It will freeze at high altitudes, more importantly it can corrode the regulator and gauge and will void any warranty.

Pulse oximetry is a nice cross check at high altitudes but should not be relied upon for various reasons, a prime one being that a little hyperventilation will artificially raise the oxygen saturation curve, giving a false sense of security. 

 

Bob Mitchell

L-320

Senior AME

 

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From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Stuart Seffern
Sent: Monday, November 24, 2008 10:01 PM
To: lml@lancaironline.net
Subject: [LML] Re: 360s at high altitudes

 

I use a Standard welding Oxygen bottle which can be exchanged anywhere in the US for less than $10 and a nose cannula in a  O-360.  Don’t necessarily try this yourself.   I’ve taken AF high altitude training twice at Wright Patterson and know well my personal limits.  At 22,000, for just under 1 hour over the Rockies heading east with a 80 knot tailwind wearing a pulse oxcimeter on my finger I was above the nasty turbulence and bad WX singing my semi-hypoxic rendition of Stormy Weather and getting a suntan in smooth air.  O2 stats never dropped below 90%.  I saw fuel economy rates as high as 47 MPG!

Lancairs are amazing airplanes….