Why wait 12-24 hrs to fly?

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CoopAir

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It seems that for Non-deco diving within recreational depths, that waiting 12-24 hrs seem excessive.

If you think of going from 80 ft under to 8000' above sea level with decompression stop (on the surface at sea level) that is wayyyy longer than even the longest deco stop that tech divers do when coming up from 200' lets say (I think 45-60 min of total deco if they come from 200' for 15 min BT on air)

So why for just an 8 ft equiv of water depth pressure change would you need a 12 hour deco stop before going to 8000'

(I use that term loosely as thats what it really is when you have a 12 hr deco stop on the surface before only going up the equiv of another 8 feet)

Doesn't make sense. Seems like any rec dive within NDL that you should be OK to go to 8000' in an hour or so just by comparing it to the deco obligation times of deep divers.
 
One of the arguments that is made is that you have to consider the possibility of depressurization of the cabin. Personally, I think that if the cabin of my jet depressurizes at 35,000 feet, I have more than DCS to worry about. :)

In fact, there have been documented cases of people developing symptoms on airplanes. It does not really make very much sense, precisely as you point out, given the pressure differentials and the times involved. I have heard it said that if you get bent from flying, you were bent before you went up, which makes a lot more sense to me; the idea being that you probably had some mild symptoms you didn't recognize, that were made worse by flying.

However, the only collected data we have has been analyzed by the people who do such things, and they concluded that, since there were really no well documented cases of DCS occurring on airplanes if the diver waited 12 hours after a single dive, or 18 after multiple dives, that those numbers were safe. It is not as though one could do a randomized controlled trial of such things . . .
 
I typically wait 24 hours because it usually takes that long for my gear to dry....
 
I'd have to believe that a lot of the reason is relative pressures. You know how people keep saying the pressure gradient is greatest very shallow? It's the same thing, but more pronounced in the air. Yeah, it's only the equivalent of 8fsw....but the pressure at 35000ft is 25% of the atmosphere at sea level. That's a HUGE difference if the plane depressurizes. Even at 8000ft, it's still 60% of the pressure at sea level. HUGE difference.
 
I've heard that getting bent on an airplane is very bad. Also, treatment delays, diverting the flight if you're really in bad shape would be a big deal.
 
It seems that for Non-deco diving within recreational depths, that waiting 12-24 hrs seem excessive.

If you think of going from 80 ft under to 8000' above sea level with decompression stop (on the surface at sea level) that is wayyyy longer than even the longest deco stop that tech divers do when coming up from 200' lets say (I think 45-60 min of total deco if they come from 200' for 15 min BT on air)

So why for just an 8 ft equiv of water depth pressure change would you need a 12 hour deco stop before going to 8000'

(I use that term loosely as thats what it really is when you have a 12 hr deco stop on the surface before only going up the equiv of another 8 feet)

Doesn't make sense. Seems like any rec dive within NDL that you should be OK to go to 8000' in an hour or so just by comparing it to the deco obligation times of deep divers.

Give it a try and get back to us. Good luck.

http://www.scubaboard.com/forums/ne...ried-fly-out-today-i-ended-up-being-bent.html

I want this to be a warning to anyone that reads flying 22 hrs after diving. Im writing to you from the most expensive hotel room you can get a hospital bed at St Marys in west palm beach FL. Friday morning i dove 2 100ft dives on air 40min 45surface 17min down again on a wreck in Key west. I took off at 7:20am the next day back to phoenix when the aircraft got to about 10 k feet started to feel strange my left hand and arm started to tingle then my right arm and both legs.I knew exactly what happened. the plane landed back at the airport and i was air lifted a helocopter here spent 5 hrs in the chamber on 100% o2. I had all my gear in my checked bags so i might not have the exact time correct just going from memory. I learned a lesson could have been a lot worse. Im still feeling the tingle in my leg off o2 so ill do another dive in the chamber again tomorrow morning.
 
My wife is a school teacher and told me this. One of the kids, a 7th grader, had gone diving in St. Thomas over Presidents Day weekend. Apparently he dived Sunday and Monday, flew home Tuesday and showed up at school with incredibly painful joints, elbows and knees, on Wednesday. The school nurse sent him to the emergency room where he was diagnosed with DCS and spent the next two days in the hospital's hyperbaric chamber. He didn't get bent until after he got off the plane. Per the boy, he never exceeded 40 feet or his NDL times. His father thought that a 4 hour interval between diving and flying would be sufficient.
 
DAN has done some trials:

Scuba Dive Medical Articles ? Decompression, Heart Safety ? DAN | Divers Alert Network

Because of neurological DCS, the surface intervals for three, six and nine hours were rejected. Ten-, 11- and 12-hour surface intervals, however, were considered acceptable according to the acceptance/rejection rules described above. The 10-hour surface interval produced one ambiguous symptom in 23 trials, but the 11- and 12-hour surface intervals had no symptoms in 23 and 27 exposures.
 
oh heck. Its all a conspiracy between the dive organizations and the various Chambers of Commerce to get divers (type-A personalities) without their vice..... Studies have shown that the withdrawal from diving, especially in a tropical destination, leads to spending of large sums of money......

But seriously, I guess I'd rather be well in a safe zone than dealing with 200 people more on a flight, and trying to make an unscheduled stop.....
 
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Interesting timing of this thread. I was always of the understanding that the wait was 24 hours, until a year or two ago when I heard some agencies suggested 12 hours would be fine.

Here's my situation. Next Tuesday I'm scheduled to dive the Spiegal and Duane (90-100ft) in the morning, and a couple shallow reefs in the afternoon. I'm also considering a 1-tank night dive on a shallow reef (no deeper than 30-40 ft). My flight takes off the next day at 6:30pm. being that the night dive will likely end around 8:00 - 9:00pm on Tuesday, I will have no problem with that 12 wait; however, I will be short a couple hours on a 24 hour wait. The flight is not too long if that makes a difference (Tampa to Baltimore). I wish there was a dive shop in Key Largo that does a Monday night dive.


Steve
 
https://www.shearwater.com/products/swift/

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