Mark, we all know there is no "magical transition". 10,000' is what has been considered acceptable for the average person. I also never said anything about the reduction in partial pressure from, as you say, 98% to 90% being negligible, what I said was the effect of hypoxia was negligible. I have no problem with rules being changed to allow us to transit to higher altitudes without supplementary oxygen. However, there is a limit to what the body will operate at without such.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mark Newton Sent: Thursday, 26 August 2004 12:20 AM To: Discussion of issues relating to Soaring in Australia. Subject: Re: [Aus-soaring] Regulation and Policing Christopher H Thorpe wrote: > Above 10,000' skill levels and judgment > start to deteriorate, getting more pronounced with altitude. You could > argue altitudes and exposure times all you like but in the end you cannot > change the laws of nature. Is there some magical transition which occurs between 9,999' and 10,000' which suddenly turns a perfectly competent pilot into a menace? If there isn't, then I think any rational person can only conclude that the laws of nature have very little to do with this limit, and that it has been set arbitrarily. You've essentially said that yourself in your post: > The fact is hypoxic effects kick in at much lower levels and > tolerances vary with individuals. If tolerances vary with individuals, why would an individual who can operate competently at (say) 12,000' be held to the same legal limit as a pilot who can operate competently at 10,000'? Or 8,000'? And if there exists a pilot who can operate competently at 12,000', how can you say a 10,000' limit is based on laws of nature instead of arbitrariness? If the rule has been set with safety as the prime concern, why not lower the limit to 5,000'? > tests have shown that up to 10,000' the effect of reduced partial > pressure is generally negligible. With all due respect, Christopher, tests have shown that up to 10,000' the effect of reduced partial pressure results in a change in blood oxygen concentration from 98% to 90% -- Hardly negligible! But that isn't the important thing. The important thing is whether that change makes a negligible or non-negligible difference to aviation safety standards. ... which brings us right back to the last paragraph in my last message: >> Sadly, that kind of review process is almost never carried out once >> a rule has been put into action. Rules are to be written and >> followed, not questioned and changed. - mark -------------------------------------------------------------------- I tried an internal modem, [EMAIL PROTECTED] but it hurt when I walked. Mark Newton ----- Voice: +61-4-1620-2223 ------------- Fax: +61-8-82231777 ----- _______________________________________________ Aus-soaring mailing list [EMAIL PROTECTED] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [EMAIL PROTECTED] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
