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Scuba Forum / General / July 2004Time between dive and airline flight
Just to refresh my memory, I will be taking some "refresher dives" when I'm in Miami Beach next month. I'll probably do it one afternoon. How much time do I need between my dives and getting back home on my return flight? Any comments will be appreciated. Thanks, Sy  SignaturePlease post and reply to sytech@yahoo.com > Just to refresh my memory, I will be taking some "refresher dives" when > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 3 lines] > > Any comments will be appreciated. 24 hours. Aren't you certified? This is usually a stressed point in cert classes. Gordon in Austin Um, you might want to check the Dan Web site. It says: The following guidelines are the consensus of attendees at the 2002 Flying After Diving Workshop. They apply to air dives followed by flights at cabin altitudes of 2,000 to 8,000 feet (610 to 2,438 meters) for divers who do not have symptoms of decompression sickness (DCS). The recommended preflight surface intervals do not guarantee avoidance of DCS. Longer surface intervals will reduce DCS risk further. * For a single no-decompression dive, a minimum preflight surface interval of 12 hours is suggested. * For multiple dives per day or multiple days of diving, a minimum preflight surface interval of 18 hours is suggested. * For dives requiring decompression stops, there is little evidence on which to base a recommendation and a preflight surface interval substantially longer than 18 hours appears prudent. 24 hours is certainly safe, but according to DAN, not necessary. g > > [quoted text clipped - 12 lines] >Gordon in Austin > >> Just to refresh my memory, I will be taking some "refresher dives" when >> I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 4 lines] >24 hours. Aren't you certified? This is usually a stressed point in >cert classes. It may be, but it has little bearing with reality. MHK would show up to the airport with his hair still wet. Lots of variables, more than can result in one or two set answers. I strive for a late morning flight out so I can still do the morning 2 tanker the day before. That translates to about 20 hours. SignatureJason O'Rourke www.jor.com > > Just to refresh my memory, I will be taking some "refresher dives" when > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 6 lines] > 24 hours. Aren't you certified? This is usually a stressed point in > cert classes. 24 hours? You got to be f.cking kidding. More likely you own a hotel in Miami Beach. Brian Edmonton, Alberta > > Just to refresh my memory, I will be taking some "refresher dives" when > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 6 lines] > 24 hours. Aren't you certified? This is usually a stressed point in > cert classes. Lighten up. The guy's taking a refresher course because he wants to refresh his knowledge and skills. Asking about the time to fly, specifically to refresh his memory on the topic, isn't a bad idea. The answer to the original question is "we don't know." 24 hours us considered, by most, to be sufficient time, but there are some who believe there's no risk and some that believe 24 hours isn't long enough. Personally, I leave a minimum of 24 hours between an aggressive diving schedule and my flight or at least 12 hours after shallow water, not even close to deco dives. Lee > > > Just to refresh my memory, I will be taking some "refresher dives" when > > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 10 lines] > his knowledge and skills. Asking about the time to fly, specifically to > refresh his memory on the topic, isn't a bad idea. I wasn't aware that I was being "heavy"; I certainly didn't intend to be. My apologies if I offended anyone. I'm aware that there is some disagreement on this subject, but in the classes I took, the "24 hours before flying" was emphasized (rightly or wrongly) nearly as much as the "don't hold your breath". It's probably a good first approximation, anyway. I am still puzzling over the "hotel in Miami beach" comment, though. ;^) Gordon in Austin > I'm aware that there is some disagreement on this subject, but in the > classes I took, the "24 hours before flying" was emphasized (rightly or > wrongly) nearly as much as the "don't hold your breath". It's probably > a good first approximation, anyway. And when I took classes being a "D" diver was emphasized, which probably was a recommendation as based in fact as any of the recommendations made since then. > I am still puzzling over the "hotel in Miami beach" comment, though. > ;^) The 24 hour rule benefits hotel owners because it makes divers stay, and therefore pay, for another night's accommodations. Brian Edmonton, Alberta > > I am still puzzling over the "hotel in Miami beach" comment, though. > The 24 hour rule benefits hotel owners because it makes divers stay, and > therefore pay, for another night's accommodations. . . . and look for something other than diving to do, often with the assistance, and a commission to, the hotel. Lee > > I'm aware that there is some disagreement on this subject, but in the > > classes I took, the "24 hours before flying" was emphasized (rightly or [quoted text clipped - 10 lines] > The 24 hour rule benefits hotel owners because it makes divers stay, and > therefore pay, for another night's accommodations. You just shouldn't have to explain good comedy! Dave. >>Just to refresh my memory, I will be taking some "refresher dives" when >>I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 8 lines] > > Gordon in Austin Gordon, so read this: http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=54 >>> Just to refresh my memory, I will be taking some "refresher dives" when >>> I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 11 lines] > Gordon, so read this: > http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=54 Well I'm a professional pilot and a new diver. I always try to leave at least 24 hours between dive and fly. I fly on a business jet, so the cabin is lower than on a airliner, even if we fly higher, but you have to consider the possibility of a loss of pressurization, you might find yourself at 30000 ft in few minutes. Gabriele Since the bends could be catastrophic to not only you but others, you are wise to be very conservative even if you lose some diving. You might want to find someone knowledgeable to give you specific advice for your situation. gabriele wrote:... > Well I'm a professional pilot and a new diver. > [quoted text clipped - 4 lines] > > Gabriele > Well I'm a professional pilot and a new diver. > > I always try to leave at least 24 hours between dive and fly. I fly on a > business jet, so the cabin is lower than on a airliner, even if we fly > higher, but you have to consider the possibility of a loss of > pressurization, you might find yourself at 30000 ft in few minutes. If you fly a biz jet you might find yerself a lot worse off than 30000ft.....and it could take a few seconds, not minutes. Dave. >>Well I'm a professional pilot and a new diver. >> [quoted text clipped - 7 lines] > > Dave. You would really have to lose the cabin door to loose pressurization in few seconds. For a window or 2 it will take a moment and then you would already be in an emergency descent. It should take 3 minutes for a descent from 45000' down to 10000', so you should meet the cabin in the thirties. Gabriele If you don't have a medical problem in the mean time. I would call DAN (Divers Alert Network) and ask them what their recommendations are for a professional pilot who will be at the controls. As divers, what we do is poorly documented, but you're getting way out beyond what even technical divers do. How many dives do you do? How deep? Are you doing Nitrox? If not, you ought to seriously look into it. As a non-medical doctor, I leave it to you to calculate how many atmospheres light you are at 30,000 feet and guess what this might do to your cardiovascular system if there is any nitrogen in your blood. My rough guess is that it would make your circulatory system pump something like the head on a beer. Look at this another way. With just a short dive, would you want to get shot to 30,000 feet? Not even the Navy divers try anything like this. Do you have pressurized oxygen available? Is there another pilot to assist you? >>> Well I'm a professional pilot and a new diver. >>> [quoted text clipped - 16 lines] > > Gabriele > If you don't have a medical problem in the mean time. I would call DAN > (Divers Alert Network) and ask them what their recommendations are for a [quoted text clipped - 8 lines] > rough guess is that it would make your circulatory system pump something > like the head on a beer. I'd imagine you're pretty close. > Look at this another way. With just a short dive, would you want to get > shot to 30,000 feet? Not even the Navy divers try anything like this. > > Do you have pressurized oxygen available? > > Is there another pilot to assist you? No, (*) and yes. But I'll be interested in gabrielles answers too. ;) Note the (*), O2 is usually delivered at a working pressure between 60-80psi to the mask, which is *relatively* high considering the outside conditions, though not by diving standards. Dave. >>Do you have pressurized oxygen available? > O2 is usually delivered at a working pressure between 60-80psi > to the mask, which is *relatively* high considering the outside conditions, > though not by diving standards. What is the same as diving, though, is that when the time comes you'll be breathing that O2 at ambient pressure, and it's the ambient pressure that determines whether or not you have too much N2. Short of breathing a lot more than 21% O2 for quite some time beforehand, at an ambient pressure of 30,000 feet ASL, you *will* have too much N2. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > >>Do you have pressurized oxygen available? > [quoted text clipped - 4 lines] > What is the same as diving, though, is that when the time comes you'll be breathing > that O2 at ambient pressure, Yes. and it's the ambient pressure that determines whether or > not you have too much N2. Short of breathing a lot more than 21% O2 for quite some > time beforehand, at an ambient pressure of 30,000 feet ASL, you *will* have too much N2. Do you mean if you have been breathing normal cabin air pressurized to 8k or so? I'm not sure I follow ya. If so, I agree, when a rapid decompression occurs at FL450 then yes, your N2 will load up somewhat rapidly. Dave. > and it's the ambient pressure that determines whether or > [quoted text clipped - 9 lines] > so? I'm not sure I follow ya. If so, I agree, when a rapid decompression > occurs at FL450 then yes, your N2 will load up somewhat rapidly. What I meant was that at 30k the ambient pressure will be about 40% of sea level. I expect that you have a better formula than the one I use which is a drop of 3% for each successive 1000 feet (so 30K is roughly .97^30). Assuming you haven't lost any significant N2 as a result of reduced cabin pressure yet (or breathing a richer mixture than 21%) and are at equilibrium with sea level pressure, exposure to 30k will mean you have 2.5 times the N2 relative to equilibrium at 30k. That's analagous to an ascent from 50 feet to the surface, after a dive that's long enough for all the different compartments to be saturated, and I don't think that any of the models indicate that's a good idea. BTW, I've been assuming that Gabriele is a variation on Gabrielle, in whichcase it's "her" plane. I suppose it could also be a variation on Gabriel, though. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > > and it's the ambient pressure that determines whether or > > [quoted text clipped - 19 lines] > different compartments to be saturated, and I don't think that any of the models > indicate that's a good idea. Agreed, and no I don't have a better formula. Thanks for the explanation. > BTW, I've been assuming that Gabriele is a variation on Gabrielle, in whichcase it's > "her" plane. I suppose it could also be a variation on Gabriel, though. Yeah, I figgered he or she was already pissy enuf at me for me to start calling him a her. If the mistake was the other way around, I assumed I could be forgiven! ;) Dave. > >>Well I'm a professional pilot and a new diver. > >> [quoted text clipped - 12 lines] > It should take 3 minutes for a descent from 45000' down to 10000', so > you should meet the cabin in the thirties. What's the difference between "a moment" and a few seconds? What is your 'time of useful consciousness' at 45,000ft? Why , if one crewmember leaves his or her position, is the other required to wear their oxygen mask above 350? Do you know what 'explosive decompression' means? Do you think losing the window at 450 wouldn't be considered an explosive decompression? Enquiring minds and all. ;) Dave. >Well I'm a professional pilot and a new diver. Good combination. Fly us somewhere. >I always try to leave at least 24 hours between dive and fly. I fly on a >business jet, so the cabin is lower than on a airliner, even if we fly >higher, but you have to consider the possibility of a loss of >pressurization, you might find yourself at 30000 ft in few minutes. It wasn't all that long ago that a crew found themselves in a similar situation . . . well, they didn't exactly find themselves. The crash investigators found them (as I recall). Turns out it was a combination of a slow leak and a malfunctioning alarm. They just went to sleep, never to awaken. Lee > >Well I'm a professional pilot and a new diver. > > Good combination. Fly us somewhere. Heh Heh true enough, but I'm sure his engines burn $$$$ just like they all do. > >I always try to leave at least 24 hours between dive and fly. I fly on a > >business jet, so the cabin is lower than on a airliner, even if we fly [quoted text clipped - 6 lines] > slow leak and a malfunctioning alarm. They just went to sleep, never to > awaken. Yea I think they had a famous golf pro on board. Started out in FL and just flew off course until they crashed somewhere out West. Just shows to go ya...you never know like you think you know what's going to happen today. That's why I'm going through my Rescue class. Just to tilt the odds ever so slightly towards I or those with me on my next dive not getting dead or any injuries minimized. > Lee > >Well I'm a professional pilot and a new diver. > [quoted text clipped - 10 lines] > slow leak and a malfunctioning alarm. They just went to sleep, never to > awaken. Yeah, it was Payne Stewarts Lear 35. I was saving that example for a question later. I have a feeling our friend isn't quite as familiar with the effects of depressurization, or more importantly, the time of useful consciousness, as they should be. Dave. >>>Well I'm a professional pilot and a new diver. >> [quoted text clipped - 20 lines] > > Dave. Nice to hear that you know me so well to judge what I know and what I don't, unfortunately I don't recall meeting you. Useful consciousness at 45000 feet is 4-5 seconds, but this is if you find yourself instantly at that altitude. This is not Hollywood! To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 secs. If you loose 1 or 2 windows,given the cabin volume and the fact that the bleeds are still pumping air it will take 5 minutes or maybe more for the cabin to reach 45000 feet. By that time you will already be at 10000' or less (3 min). The cabin when flying at 45000' is at an altitude of 6000'. Even if the door should let go, unless the fuselage breaks in a half (and then you would not have to worry about oxygen), it will take a while to loose all pressurization, and a door would not just suddenly let go without any previous warning, door unsafe light, noise, cabin altitude climbing. You get a warning at 8700'. In all the cases I had, simulator of course, the cabin never reached 30000', that i can remember. 24 hours is what is recommended by authorities, like I said that is the minimum for me and till now I did at least 48. And yes we are 2 pilots. Gabriele > Useful consciousness at 45000 feet is 4-5 seconds, but this is if you > find yourself instantly at that altitude. > To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 > secs. Is that to say that you *always* manage it faster than 3 seconds? Are you sure it will be just the same with that explosion and all the whooshing going on? > Even if the door should let go, unless the fuselage breaks in a half > (and then you would not have to worry about oxygen), it will take a > while to loose all pressurization, How long does it take with a 5 by 6' hole in the roof? Will it matter whether the hole is up front or back aft? Will you have time to lean down and kiss your a.s Aloha? But like I said in an earlier post, if you have a major loss of pressure the extra N2 probably isn't going to be your biggest concern. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > > Useful consciousness at 45000 feet is 4-5 seconds, but this is if you > > find yourself instantly at that altitude. [quoted text clipped - 4 lines] > Is that to say that you *always* manage it faster than 3 seconds? Are you sure it > will be just the same with that explosion and all the whooshing going on? g seems to think that it won't whoosh, it'll be a gentle hiss through the missing window. It takes "several minutes" according to him, even if two windows go, or even more amazingly the cabin door. In his 'plane, the 'bleed pumps' can keep up with the loss. bwaaaahahawahwah! > > Even if the door should let go, unless the fuselage breaks in a half > > (and then you would not have to worry about oxygen), it will take a [quoted text clipped - 5 lines] > But like I said in an earlier post, if you have a major loss of pressure the extra N2 > probably isn't going to be your biggest concern. This oughta be interesting. ;0) Dave. .. >To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 >secs. I appologize if I missed this, but what is the significance of "72.5 PSI"? >24 hours is what is recommended by authorities, like I said that is the >minimum for me and till now I did at least 48. The 24 hours -- more recently 18 hours -- recommendations are based on a MAXIMUM exposure altitide of 8000 ft. Although it is unlikely, it is possible that in an emergency situation the pilot of an aircraft will be exposed to a higher altitude, and thus requrie a longer wait between diving and flying. >And yes we are 2 pilots. Then it is YOUR resposibility to check the appropriate regulations. For example, I know that the FAA _requires_ pilots to wear oxygen masks above a certain altitude -- even in a pressurized aircraft. Are there regs relating to PILOTING after diving? Airline or FAA? SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > .. > >To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 > >secs. > > I appologize if I missed this, but what is the significance of "72.5 PSI"? None really. Somebody asked if it was high or low pressure coming to the mask. The working pressure on most masks in bizjets is somewhere between 60-80psi, iirc. Steve was correct though, it will basically be fed at ambient pressure regardless. > >24 hours is what is recommended by authorities, like I said that is the > >minimum for me and till now I did at least 48. [quoted text clipped - 4 lines] > exposed to a higher altitude, and thus requrie a longer wait between > diving and flying. I'm too lazy, so I was wondering if anyone knows off the top of their heads what standard pressure is at 45,000ft, converted to 'atmosphere's'? I remember that 29.92" is approximately 14.7psi, but that's about it. I'm wondering how decompression in an aircraft compares *in reality* with a diving decompression incident. > >And yes we are 2 pilots. > > Then it is YOUR resposibility to check the appropriate regulations. > For example, I know that the FAA _requires_ pilots to wear oxygen > masks above a certain altitude -- even in a pressurized aircraft. > Are there regs relating to PILOTING after diving? Airline or FAA? I'm not aware that the FAA hsa ever addressed the issue of flight crewmwmbers and diving, but the wearing of O2 mask regs *certainly* don't take that into consideration. Unless the regs have changed since I last flew (which is entirely possible) when our bud flies at 450 he or his other crewmember is required to wear a mask at all times, ie, obove 410. Between 350 and 410, one is only required to be actually *wearing* their mask if the other crewmember leaves his station. Dave. >I'm too lazy, so I was wondering if anyone knows off the top of their heads >what standard pressure is at 45,000ft... There's is a kinda neat chart at http://www.engineeringtoolbox.com/25_462.html From that: Sea Level - 14.696 psi 10,00 ft -- 10.1 20,00 ft -- 6.78 30,00 ft -- 4.37 40,00 ft -- 2.73 45,00 ft -- 2.14 2.14:14.696 works out to be 1:6.87. This is equivalent to the ratio of the surface to about 176 fsw. If you're saturated with N2 at surface pressure, then, oxygen or no, you can expect to get bent at 45,000 ft if you don't get to a higher pressure (lower pressure altitude) quickly. (Among other problems.) Using a ratio of 1:3, about 25,000 feet is as high as you'd like to go if you want to avoid bends. And if you have MORE N2 that surface saturation, you'd better stay lower. Another point of reference -- Mt Everest is just a bit under 30,000 ft; it is possible to climb Mt Everest without suplimental oxygen. I would expect that a pilot at around 30,000 feet could continue to function at ambient (outside) air pressure for a reasonable period of time. So the FAA seems reasonably in line on this. .. >crewmember is required to wear a mask at all times, ie, obove 410. Between >350 and 410, one is only required to be actually *wearing* their mask if the >other crewmember leaves his station. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > In article <QxxLc.119660$OB3.7246@bgtnsc05-news.ops.worldnet.att.net>, (snip)> If you're saturated with N2 at surface pressure, then, oxygen or no, > you can expect to get bent at 45,000 ft if you don't get to a higher > pressure (lower pressure altitude) quickly. (Among other problems.) Ah, there we go, back on track. Phew. > There's is a kinda neat chart at http://www.engineeringtoolbox.com/25_462.html > [quoted text clipped - 8 lines] > > 2.14:14.696 works out to be 1:6.87 A simple rule of thumb I've used is that the pressure drops a bit over 3% with each additional 1000 feet of altitude. It's not 3% of sea level pressure each time, but 3% of the current pressure, ie, pressure at 10,000 is about 97% of pressure at 9000. If you remember that it's actually closer to 3.5% it works quite well to altitudes at which you can out your feet on the ground. Not perfect, but something you might actually remember off the top of your head. > Another point of reference -- Mt Everest is just a bit under 30,000 ft; > it is possible to climb Mt Everest without suplimental oxygen. > I would expect that a pilot at around 30,000 feet could continue > to function at ambient (outside) air pressure for a reasonable > period of time. If that pilot had just spent a couple of weeks at 20k feet becoming acclimated you'd have a good point. A climber that flew into base camp from even 10k feet wouldn't have a prayer of functioning at 30k the following morning. A pilot that's acclimated to an altitude that's close to sea level can expect a very short period of uesful consciousness when suddenly exposed to ambient pressure at 30k. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > >I'm too lazy, so I was wondering if anyone knows off the top of their heads > >what standard pressure is at 45,000ft... [quoted text clipped - 15 lines] > you can expect to get bent at 45,000 ft if you don't get to a higher > pressure (lower pressure altitude) quickly. (Among other problems.) Thatnks, that is exactly what I was trying to get at. I only remembered approximate numbers up to about 20,000 and that it levels off quite a bit the higher you go. > Using a ratio of 1:3, about 25,000 feet is as high as you'd like to > go if you want to avoid bends. And if you have MORE N2 that surface > saturation, you'd better stay lower. > > Another point of reference -- Mt Everest is just a bit under 30,000 ft; > it is possible to climb Mt Everest without suplimental oxygen. Not for the average person. The climbers who climb even close to those altitudes without suplemental O2 spend weeks aclimatising. They climb up, then descend again just for that sole purpose. > I would expect that a pilot at around 30,000 feet could continue > to function at ambient (outside) air pressure for a reasonable > period of time. So the FAA seems reasonably in line on this. Again, I don't recall the numbers for time of useful consciousness at different altitudes, but I suspect that going from 6 or 8k to 30 in a matter of seconds is actually quite debilitating, should you not get the mask on fairly quickly. Certainly, at the higher alt's, (high 30's and lower 40's) it is in the few second range. > .. > >crewmember is required to wear a mask at all times, ie, obove 410. Between > >350 and 410, one is only required to be actually *wearing* their mask if the > >other crewmember leaves his station. Dave. > None really. Somebody asked if it was high or low pressure coming to the > mask. The working pressure on most masks in bizjets is somewhere between > 60-80psi, iirc. Steve was correct though, it will basically be fed at > ambient pressure regardless. I'm just making an assumption here, but isn't it a demand valve? That makes it essentially similar to a SCUBA regulator, except that the intermediate pressure is apparently only about half as much. One might wonder why that presure was pointed out in the first place, since all you really need is 14.8 at a suitably high flow rate. > I'm too lazy, so I was wondering if anyone knows off the top of their heads > what standard pressure is at 45,000ft, converted to 'atmosphere's'? Charlie's chart may be 100% accurate, but above 10k it increases in increments of 5k, leaving you to interpolate if you want values for other altitudes. As long as you're gonna do math anyway, a fairly accurate approximation is .965 raised to the power of the altitude in 1000's of feet. 10K = .965^10 = .700 ATA, vs the .687 from the chart(indirectly, since ATA isn't one of the listings). In scientific mode the calculator that comes with Windows will be happy to do the math for you. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. >I'm just making an assumption here, but isn't it a demand valve? ... I believe that constant flow devices are used. In some cases nasal canulas are used. (I've probably miss-spelled "canula"; my spell-checkrer is not helpful.) SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > > None really. Somebody asked if it was high or low pressure coming to the > > mask. The working pressure on most masks in bizjets is somewhere between > > 60-80psi, iirc. Steve was correct though, it will basically be fed at > > ambient pressure regardless. > > I'm just making an assumption here, but isn't it a demand valve? In the a/c I used to fly I believe the crew mask was demand and the pax masks were constant flow.. That makes it > essentially similar to a SCUBA regulator, except that the intermediate pressure is > apparently only about half as much. One might wonder why that presure was pointed out > in the first place, since all you really need is 14.8 at a suitably high flow rate. Well, somebody asked if high the supply was high pressure, and I fell into the trap of providing the intermediate pressure, which you quickly and correctly noted was irrelevant. > > I'm too lazy, so I was wondering if anyone knows off the top of their heads > > what standard pressure is at 45,000ft, converted to 'atmosphere's'? [quoted text clipped - 5 lines] > chart(indirectly, since ATA isn't one of the listings). In scientific mode the > calculator that comes with Windows will be happy to do the math for you. Yeah, that's what I was asking. I wondered how the changes equated to the units we are familiar with for diving. Dave. > >>>Well I'm a professional pilot and a new diver. > >> [quoted text clipped - 8 lines] > >>situation . . . well, they didn't exactly find themselves. The crash > >>investigators found them (as I recall). Turns out it was a combination of a > >>slow leak and a malfunctioning alarm. They just went to sleep, never to > >>awaken. [quoted text clipped - 6 lines] > Nice to hear that you know me so well to judge what I know and what I > don't, unfortunately I don't recall meeting you. You didn't have to. I was judging by your post, not that it was very specific. > Useful consciousness at 45000 feet is 4-5 seconds, but this is if you > find yourself instantly at that altitude. [quoted text clipped - 3 lines] > To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 > secs. I've done it many times. It takes about 3 seconds when you're sitting there thinking, "I'm going to put my mask on now". > If you loose 1 or 2 windows,given the cabin volume and the fact that the > bleeds are still pumping air it will take 5 minutes or maybe more for > the cabin to reach 45000 feet. I guess a lot of variables are involved, most considerably being the cabin volume and the size of the window.....but in general terms, I disagree. I think losing a window in a small bizjet at 450 would take a few seconds, not a few minutes to almost completely depressurize. > By that time you will already be at 10000' or less (3 min). > [quoted text clipped - 3 lines] > (and then you would not have to worry about oxygen), it will take a > while to loose all pressurization, I disagree. I think you'd be busy wondering wtf just happened while spilling yer hot coffee on yer nuts, panicking over all the alarms that just went off and trying to grab yer mask before you blacked out. But that's just my opinion. I'm glad to hear that in your world when your cabin door disappears you have several minutes to do your emegency descent, read the checklist and serve the pax another scotch and water while ur at it. > 24 hours is what is recommended by authorities, like I said that is the > minimum for me and till now I did at least 48. Prolly the smartest thing you've said. Dave. >> To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 >> secs. > >I've done it many times. It takes about 3 seconds when you're sitting there >thinking, "I'm going to put my mask on now". Two problems: (1) It takes LONGER than 3 seconds when your not sitting there ready to put on the mask asap -- and you won't be, becuase your flying the airplane. (2) 3 seconds is too long. In an emergence you need to aviate *NOW*. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > >> To put on a Quick donning mask, pumping up to 72.5 PSI takes less than 3 > >> secs. [quoted text clipped - 7 lines] > ready to put on the mask asap -- and you won't be, becuase your > flying the airplane. Absolutely, that was the point I was trying to make. > (2) 3 seconds is too long. In an emergence you need to aviate *NOW*. Actually that is good advice for a student pilot. Aviate, navigate, communicate. Problem is, when ur at 450 and you depressurize, you have about 4-5 seconds before you black out.....so putting the mask on becomes job #1. Period. Dave. > ... Problem is, when ur at 450 and you depressurize, you have about >4-5 seconds before you black out.....so putting the mask on becomes job #1. >Period. Not if you already HAVE it on -- as required. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > > ... Problem is, when ur at 450 and you depressurize, you have about > >4-5 seconds before you black out.....so putting the mask on becomes job #1. > >Period. > > Not if you already HAVE it on -- as required. One of the crewmembers is required to be wearing the mask. That is in gabriels world. When I flew, *always* at 410 or below, it was not required at all. THEN it becomes job #1. Dave. > > Yeah, it was Payne Stewarts Lear 35. I was saving that example for a > > question later. I have a feeling our friend isn't quite as familiar with the [quoted text clipped - 3 lines] > Nice to hear that you know me so well to judge what I know and what I > don't, unfortunately I don't recall meeting you. If you'd met me, you'd remember! Are you done pissing and whining now? > And yes we are 2 pilots. Thank God! Dave. Gabreile, I'm glad that you like diving enough to want to do it so much. The flying after diving is clearly not a settled issue. There are lots of unknowns. If you check Divers Alert Network or talk to a dive physician they will tell you this. The 24 hours is based on gradual decompression, not sudden. There's a difference between opening a beer or soda quickly and slowly. You're the quick version. Getting oxygen in a mask in 2-3 seconds is great, but will it get the pressure in your lungs back to sea level? Well, at 30,000 feet that too could be fatal. It's not only the oxygen, it's the pressure. I can get bent (and fatally going from 200 feet to 10 feet under the surface) without anything like the pressure changes you're talking about. If you want to take your own chances (as we all do when we dive) that is one thing. I go diving and fly after 24+ hours, but if something goes wrong I am the only hurt because I'm not the pilot. The FAA says as a pilot you can't have a drink within 24 hours of flying. Do they have any rules about diving and flying? To paraphrase something about flying, my goal is not to be the best diver. I want to be the oldest diver. Very seriously. We've all made some suggestions. You need to find some real expert opinions in dive and flight medicine. Calling DAN (you don't need to be a member) is a good, professional start. If you have to pay for some of the advice, it could turn out to be money well spent. Call the Air Force Academy and see if they don't have someone there who knows something about this who will talk to you. Or call the Naval Academy. > Gabreile, > [quoted text clipped - 30 lines] > knows something about this who will talk to you. Or call the Naval > Academy. This discussion split in 2 threads: Flying after diving: Spoke with DAN, they say that for few repetitive recreational dives, like you might do in one week in the Caribean, after 24-36 hours you are back to normal, from here the depressurization problem does not have to do with diving. Aeronautical authorities reccomend 24 hours, one says if dive do not require a stop then 4 hours, if deco stop then 24. Flight operations: Yes I agree that it will take more than 3 secs to don the mask, with the nise, air rush, fog, and the "what the .... was that" it will probably take between 5 and 10 secs. Yes you have to aviate, but you have to put your mask on, somene suggesting otherwise? The aeroplane would be on autopilot and should remain on it, emergency descent is done on autopilot, one type of long range biz jet have a single switch to perform the descent automatically, others will have it soon too. Never said that the bleeds are going to keep up but that they will still pump air, not doing much probably I agree. Spoke with the manufacturer, says for loss of the door cabin takes 30 secs to depressurize, less that what I expected but still enoght to have your mask on and be in descent. Masks deliver at ambient or slightly over depending on pilot selection: -Normal diluted on demand. -100% oxy on demand -100% oxy continuos flow. So, depressurization at high altitude should be survivable, of course Murphy is always around the corner but this is what we got and we have to do our best with it. Unfortunately I'll be away for one week without access to the newsgroup (no diving don't worry) so I will not be able to follow up on the thread, but I'll sure check in at a later date. All the best to everybody. Gabriele (variation of Gabriel) > Aeronautical authorities reccomend 24 hours, one says if dive do not > require a stop then 4 hours, if deco stop then 24. Do you have a reference for that? I'm not attacking you, I am interested to know. > Flight operations: > Yes I agree that it will take more than 3 secs to don the mask, with the > nise, air rush, fog, and the "what the .... was that" it will probably > take between 5 and 10 secs. Better. > Yes you have to aviate, but you have to put your mask on, somene > suggesting otherwise? > The aeroplane would be on autopilot and should remain on it, emergency > descent is done on autopilot, one type of long range biz jet have a > single switch to perform the descent automatically, others will have it > soon too. What are you flying? Are you type rated? (No offense, just curious). > Never said that the bleeds are going to keep up but that they will still > pump air, not doing much probably I agree. Not what you insinuated. > Spoke with the manufacturer, says for loss of the door cabin takes 30 > secs to depressurize, less that what I expected but still enoght to have > your mask on and be in descent. I'm guessing you are in a rather large cabin a/c. > Masks deliver at ambient or slightly over depending on pilot selection: > -Normal diluted on demand. > -100% oxy on demand > -100% oxy continuos flow. Depending on a/c. > So, depressurization at high altitude should be survivable, of course > Murphy is always around the corner but this is what we got and we have [quoted text clipped - 5 lines] > > All the best to everybody. Same to you, don't be so sensitive when you get back. Dave. Well I'm back earlier than planned, boss changed his mind. >>Aeronautical authorities reccomend 24 hours, one says if dive do not >>require a stop then 4 hours, if deco stop then 24. > > Do you have a reference for that? I'm not attacking you, I am interested to > know. Could not find anything exept raccomandations, I remebered Canada said something, checked the A.I.P, sais that if dive do not require deco stop pilot should not fly before 4 hours, if deco stop required then 24 h. >>Flight operations: >>Yes I agree that it will take more than 3 secs to don the mask, with the [quoted text clipped - 11 lines] > > What are you flying? Are you type rated? (No offense, just curious). A Global Express, yes type rated. >>Never said that the bleeds are going to keep up but that they will still >>pump air, not doing much probably I agree. > > Not what you insinuated. Well probaly didn't express myself well >>Spoke with the manufacturer, says for loss of the door cabin takes 30 >>secs to depressurize, less that what I expected but still enoght to have >>your mask on and be in descent. > > I'm guessing you are in a rather large cabin a/c. Yes quite largest cabin for Business Jets, next step up would Boeing or Airbus >>Masks deliver at ambient or slightly over depending on pilot selection: >>-Normal diluted on demand. >>-100% oxy on demand >>-100% oxy continuos flow. > > Depending on a/c. I can talk only about the aircraft I know. >>So, depressurization at high altitude should be survivable, of course >>Murphy is always around the corner but this is what we got and we have [quoted text clipped - 7 lines] > > Same to you, don't be so sensitive when you get back. I came here to give my opinion and hear other's. I felt you were judging my knoledge and saying I was doing something dangerous. > Dave. Gabriele > Well I'm back earlier than planned, boss changed his mind. > [quoted text clipped - 7 lines] > something, checked the A.I.P, sais that if dive do not require deco stop > pilot should not fly before 4 hours, if deco stop required then 24 h. Transport Canada told you that? I'd be amazed. You fly out of canada? > >>Flight operations: > >>Yes I agree that it will take more than 3 secs to don the mask, with the [quoted text clipped - 6 lines] > > A Global Express, yes type rated. Nice. you should know more about your a/c. though. > >>Never said that the bleeds are going to keep up but that they will still > >>pump air, not doing much probably I agree. > > > > Not what you insinuated. > > Well probaly didn't express myself well you said, > If you loose 1 or 2 windows,given the cabin volume and the fact that the > bleeds are still pumping air it will take 5 minutes or maybe more for > the cabin to reach 45000 feet. I don't think it was an error in expressing yourself. I think what you said was absolutely incorrect. > >>Spoke with the manufacturer, says for loss of the door cabin takes 30 > >>secs to depressurize, less that what I expected but still enoght to have [quoted text clipped - 4 lines] > Yes quite largest cabin for Business Jets, next step up would Boeing or > Airbus Even on a GE, I'd still have guessed that explosive decompression due to loss of cabin door would take significantly less than 30 seconds. Still, if you say the manufacturer said so...... > >>All the best to everybody. > > > > Same to you, don't be so sensitive when you get back. > > I came here to give my opinion and hear other's. I felt you were judging > my knoledge and saying I was doing something dangerous. I was judging your knowledge by the content of your posts. Dave. > Transport Canada told you that? I'd be amazed. > You fly out of canada? They didn't tell me, is in the A.I P. >>A Global Express, yes type rated. >> >>Well probaly didn't express myself well > > I don't think it was an error in expressing yourself. I think what you said > was absolutely incorrect. > Even on a GE, I'd still have guessed that explosive decompression due to > loss of cabin door would take significantly less than 30 seconds. Still, if > you say the manufacturer said so...... > I was judging your knowledge by the content of your posts. > > Dave. Whatever. Take care. Gabriele > Gabreile, > [quoted text clipped - 12 lines] > 10 feet under the surface) without anything like the pressure changes > you're talking about. Exactly. > If you want to take your own chances (as we all do when we dive) that is > one thing. I go diving and fly after 24+ hours, but if something goes > wrong I am the only hurt because I'm not the pilot. uh-huh! > The FAA says as a pilot you can't have a drink within 24 hours of > flying. Do they have any rules about diving and flying? I don't recall any. I will look when I get the time. > To paraphrase something about flying, my goal is not to be the best > diver. I want to be the oldest diver. [quoted text clipped - 6 lines] > who knows something about this who will talk to you. Or call the Naval > Academy. All well said. Dave. > It wasn't all that long ago that a crew found themselves in a similar > situation . . . well, they didn't exactly find themselves. The crash > investigators found them (as I recall). Turns out it was a combination of a > slow leak and a malfunctioning alarm. They just went to sleep, never to > awaken. When you think about it, they were lucky........that's the way to go! ;0) Dave. You are referring to a flight carrying a professional golfer (if I remember correctly) which was on auto-pilot. Flight controllers couldn't contact the pilot and the plane eventually ran out of fuel. The supposition was that there was a very slow decompression of the cabin and that they fell asleep. Bart F. >>Well I'm a professional pilot and a new diver. > [quoted text clipped - 12 lines] > > Lee > Just to refresh my memory, I will be taking some "refresher dives" when > I'm in Miami Beach next month. I'll probably do it one afternoon. > > How much time do I need between my dives and getting back home on my > return flight? http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=54 > > Just to refresh my memory, I will be taking some "refresher dives" when > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 3 lines] > > http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=54 Best answer. There has been several updates and if you are not sure you should be going to your local dive shop and take a scuba refresher course. Scott Signature------------------------------------------------------------------ Scott F. Migaldi, K9PO MI-150972 PP-ASEL-IA Are you a PADI Instructor or DM? Then join the PADI Instructor Yahoo Group at http://groups.yahoo.com/group/PADI-Instructors/join ----------------------------------- Catch the wave! www.hamwave.com **"A long time ago being crazy meant something, nowadays everyone is crazy" -- Charles Manson** > > Just to refresh my memory, I will be taking some "refresher dives" when [quoted text clipped - 8 lines] > > Sy > Just to refresh my memory, I will be taking some "refresher dives" when > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 3 lines] > > Any comments will be appreciated. Well you need to have time to get to the airport, check in, stuff like that. That about covers it unless you want to have time to get something to eat as well. Brian Edmonton, Alberta > > Just to refresh my memory, I will be taking some "refresher dives" when > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 9 lines] > That about covers it unless you want to have time to get something to > eat as well. Lets not omit the lounge. The message <10ere4e47kudv40@corp.supernews.com> from "Scott" <pugetsounddiver@gmail.com> contains these words: > > that. > > > > That about covers it unless you want to have time to get something to > > eat as well. > Lets not omit the lounge. Nah, it's simpler just to fly Logan Air/British Airways, that way there's not a hope you're going to take-off within a couple of hours of schedule anyhow - at least not to Sumburgh, saves any worrying about intervals > Nah, it's simpler just to fly Logan Air/British Airways, that way > there's not a hope you're going to take-off within a couple of hours of > schedule anyhow - at least not to Sumburgh, saves any worrying about > intervals Gotta love Logan Air/BA. I can't imagine too many other airlines that would make me fly from Kirkwall to Sumburgh so that I can connect to my flight from Sumburgh to Kirkwall. What's even funnier is that I spent 3 hours in Kirkwall waiting for Sumburgh to clear up so I could fly from Kirkwall to Sumburgh and then to Kirkwall. Brian Edmonton, Alberta www.mossmanscuba.com > > > Just to refresh my memory, I will be taking some "refresher dives" when > > > I'm in Miami Beach next month. I'll probably do it one afternoon. [quoted text clipped - 11 lines] > > Lets not omit the lounge. Definately, although you have to fly internationally to get the one with free booze :-) > Lets not omit the lounge. Absolutely. I can't believe I forgot to allow for that. Making time for the lounge is of utmost importance. Brian Edmonton, Alberta > > Lets not omit the lounge. > > Absolutely. I can't believe I forgot to allow for that. Making time for > the lounge is of utmost importance. Task saturation, clear as a Bell jar. To Us, its a no mention prerogative. I knew you were there Bra, just had to give you that Brotherly elbow to the ribs. Speaking of which; Get off your lumps and come visit. You need to come here. Let me show you around, and let Us Bless You with that unspoken commodity. Have I burned you yet? > Speaking of which; > [quoted text clipped - 3 lines] > > Let me show you around, and let Us Bless You with that unspoken commodity. Gotta be next year. Nothing on my schedule for the Wet Coast until late next spring. I was hoping to make a sidetrip when I went to Nanaimo last month but I had no extra time. If I come can we shoot guns? > Have I burned you yet? Nope. Brian Edmonton, Alberta > > Speaking of which; > > [quoted text clipped - 7 lines] > next spring. I was hoping to make a sidetrip when I went to Nanaimo last > month but I had no extra time. Brother; if you have the time, I have the crime. I already spoke to the Old Man about you, in particular and exclusive, and we'll hook you up. > If I come can we shoot guns? Absolutely. We will wear you out just loading mags. But, your ears wont ring. =;-) |
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