Reprise - Oxygen concerns

"Raphael Warshaw" wrote in message
m...

There's no doubt that pressure-demand systems using fitted masks are
the way to go for flights to high altitude(18,000 feet). My concern
is with what happens down low (between 5,000 and 18,000 feet). My
suspicion and concern is that more than a few pilots are, at
relatively low altitudes, desaturated sufficient to experience
measurable performance decrements.

Raphael Warshaw
Claremont, CA

I encountered an example of low altitude desaturation on my last flight out
of Boulder Colorado. (Elevation 5200')

I had struggled to push the ballasted Nimbus onto the runway while wearing a
parachute. Then I rushed to remove the tail dolly before struggling into
the cockpit and straps. I felt a little out of breath. (I've GOT to spend
less time at this computer and more in the gym.) I slipped the little
oxymeter cuff onto my finger as soon as I was strapped in and the SpO2 was
88%. Yikes!

I selected 100% emergency O2 and took a couple of deep breaths and my SpO2
jumped up to 99%. I have always saved a shot of straight O2 for the
landing.

I wonder how many takeoff accidents are the result of a desaturated pilot
who is out of breath from the rush to get ready. Two deep breaths of pure
O2 are now on my pre-takeoff checklist.

Bill Daniels