Flying After Diving

[Mobulai]

Seems like lots of folks are overanalyzing this (imho). I’d guess that you likely have 12 hours after you complete your dive to before you fly? If so, you are good against the widely accepted DAN guidance:

View attachment 911459

Guidelines for Flying After Diving

The recommendations for flying after diving come from a DAN study — read all about the study workshop and conclusions.

dan.org

This is a generic linearized threshold rule of what Joh has actually shared, which makes it simpler for recreational divers to have an easy buffer / calculation of their no fly times without a computer

It bases on the more complex tables that account for altitude and such

Sometimes after repetitive deco diving, my computer tells me I have 7h of no fly (because of my efficient accelerated deco)
Still good to leave a buffer

Of course when in doubt/without table, easiest/safest bet is the DAN recommendation, and to err on the side of safety

 

[chrisch]

There can never be agreement because individual human beings will have different risk tolerance. The guidlines are published by respected bodies to give a reasonable balance between risk and the needs of divers that wish to use aviation as a form of transport.

The overlooked aspect is the type of aviation which is just called "flying". Quite apart from the risk of the airplane crashing there is the additional risk of depressurisation of the passenger area - a very small risk of course. Commercial aircraft will fly at a lower altitude if this occurs and so the reduced ambient pressure is temporary.

No advice or guidline can take into account this variable. Nor the overall flight length (in time) during which any DCI cannot be treated.

The term "no fly" is therefore a rather imprecise one. The nitrogen load in slow tissue (itself only an hypothesis) could in theory cause DCI due to the lower ambient pressure of an aircraft or a land vehicle that climbs to altitude. Decompression models hypothesize that the nitrogen is excreted at a given rate and so after a period of time the tissue saturation is ambient.

The more you study the theory the more obvious it is that there are some assumptions that are at best questionable. Generally it is agreed to be cautious to minimise the risk. No one will be able to give a definative answer as there is no such answer.

The variables are too diverse for any meaningful number to be given. So it is a hunch, a guess. My guess is - you will be fine.

 

[Outbound]

Algorithm in DCs typically doesn’t use Navy tables but much rougher guidelines. The answer from John is spot on.

What do you mean by "much rougher guidelines?" My understanding is that the difference between Navy tables, the PADI RDP, and subsequent computer-based algorithms is the use of a shorter (typically 60 minute) half-time for the longest tissue compartment. You make it sound like these algorithms are just taking some guesses.

 

[LFMarm]

DAN recomendations are much rougher than the Navy tables – they do not take into account how much the tissues are saturated. That being said, they are regarded as very safe so if you follow those you should be on the side of safety.

However, I have been in situations where I had to fly much sooner than those guidelines after multiple days of deep deco diving and used the Navy tables to assess how much oxygen I needed to breathe to be safe before boarding.

 

[inquis]

What do you mean by "much rougher guidelines?"

I believe he was referring specifically to the Time To Fly algorithms in the DCs.

 

[Outbound]

I believe he was referring specifically to the Time To Fly algorithms in the DCs.

Gotcha. Makes sense now. Thanks.

 

[admikar]

The supplied air density should be at surface level.

Say what?

 

[kdlv]

Say what?

Read the other posts. Question was whether there is a difference if air is supplied from the surface via a hookah hose or comes from a tank at the same depth as you!

 

[nadwidny]

I volunteer at my local aquarium. I regularly dive the exhibits for cleaning and feeding. Depths range from 8-15 ft. Air supply is via hookah hose to compressor. Average dive time is 45 minutes. Can someone please advise whether usual flying after diving guidelines apply to these types of dives. I’m scheduled to work at the aquarium on Friday and then am flying on Saturday.

They don't. You are doing a 45 minute deco stop.

 

[tursiops]

The variables are too diverse for any meaningful number to be given. So it is a hunch, a guess. My guess is - you will be fine.

This could be interpreted to mean, "if the answer is not exact then it is useless. You may as well just guess."
I hope you did not mean that, because it is a silly thing to say.