Shallow dives during the no-fly desat time?

[hudson]

I was wondering if one can make a shallow dive or two during a typical no-fly period of 24 hours, without extending it..

Specifically, I'm thinking of ending my Cozumel trip with a coupole of cenote dives with a maximum depth of 22 (or 32 - I need to check) ft in the morning and flying ~3hrs after the second dive, if possible. This would be at the end of a week of diving. Bad idea? What if I allowed for the full desat time to elapse BEFORE the cenote dives?

 

[spectrum]

Bad idea, I thnnk so.

For openers, here's what DAN says about flying after diving:
Revised Flying After Diving Guidelines for Recreational Diving - May 2002

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.

So If you take a day off to clear your system for flying. Then made a single non-deco dive you could fly in 12 hours. However If you have been diving intensively I'm not so sure that you are really 100% offgassed in 18 hours so going back for one on the 12 hour rule could be something of a double dip.

As for flying 3 hours after the dive that's certainly out of the question.

Pete

 

[Zippsy]

As I understand it, it's the long shallow dives before flying that are a bigger concern than the short deep dives. Either way, I'd stick with the DAN reccommendations or be more conservative.

 

[Thalassamania]

Short deep dives are of less concern than longer shallow dives since you only load fast tissues which clear also fast.

DAN’s recommendations are prudent, perhaps overly so, but that’s their role. In the bad old days the guideline was U.S.Navy Group “C” until we realized that at 8,000 feet a diver who had just crossed over from “B” to “C” was OK but a diver who was in “C” about to go to “D” was not. So we moved the spec to Group “D.”

On many occasions I’ve had to fly sooner than a prudent DAN recommendation would permit. Sometimes we could keep the aircraft below 500 ft, but sometime we could not. For those occasions we used tables that credit you for surface interval oxygen breathing (you can also use a lot of decom software to cut tables starting pure oxygen at 20FSW for faster washout). If I recall, and please don’t bet your life on my recollection, two hours of surface 100% oxygen will take you from Group N down to Group A.

Remember, your spinal cord has beeen good to you, be good to it.

 

[Darren27]

Enjoy your weeks diving and then spend the last day getting wrecked in the bar, why risk DCI when the beers cold and you still on holiday.