SCUBA Decompression & Low altitude flying

[WannaBeBiggles]

Happy new year all

after doing some diving in the pacific recently and watching beavers fly tourists around the islands I got to thinking.

We all know that diving, especially if the dive required a decompression stop, and flying straight afterwards is a big no no. However, if one were to do a dive from a float plane and return home at 500-1000ft, would the effects of altitude be negligible and could you work out your safe nitrogen levels based on the knowledge of altitude?

As far as I see it, it would be no different to doing a high altitude dive in a lake on a mountain. (Granted that that requires additional training and comes with it's own set of dive charts)

I tried googling this but to no avail, so thought I'd throw the question out there.

[Flying Binghi]

if one were to do a dive from a float plane and return home at 500-1000ft

Disclaimer - i aint no expert. Consult with a professional diver/dive instructor before flight.

Do the sums - Been years since i've done any dives though from memory the negative pressure change from sea level to 500' is about the same amount as the positive change diving to a 6 inch depth... or was it 6 foot... something like that.

Dive off a Beaver (float plane that is) The Beavers climb rate is that leisurely it shouldn't worry ya ...though i probably wouldn't go above 500 odd feet.




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[Aerodynamisist]

Might be worth asking the medical forum, blood gasses and partial pressures are there forte.

[VH-XXX]

I'd ask a dive instructor or a dive shop guy, this has to be the most common question asked by tourists. They will have all the numbers. You could easily reach 500-1000 ft when driving home. 8,500ft pressurization on an airliner is a different story completely.

[Captain Nomad]

Don't forget that air pressure change with increasing altitude is not linear and the greatest RATE of pressure change occurs within the first thousand feet or so... That's why medical people get all excited about 'sea level cabin' requirements on medical flights with patients suffering pressure sensitive medical conditions.

[PA39]

Being a diver you would understand that 1 AT = 30' so if you have had a recent deco dive ( say 60+mts/ x time) it would be necessary to fly low. It doesn't apply to "shallow" dives in my book. We used to always fly back from the islands at 1000' after a heavy dive.

[aussie027]

Wannabebiggles--

There was a detailed safety article about this exact subject years ago, the link below will give you a copy of one of them, just cut and paste into your browser URL window--

flightsafety.org/hf/hf_sep-oct91.pdf

These links are more general articles from diving organizations--

Unexpected Decompression Illness | Feature Article by Divers Alert Network on DeeperBlue.com

The Basics of Flying and Scuba Diving

Is Flying After Diving Safe : Divetime.com : Scuba Diving Articles

That should answer most of your Q.

[Sunfish]

If you own a dive computer, then read your dive computer instructions. It allows you to compensate for diving in mountain lakes, etc. Effectively all you are doing is climbing 500 ft above where you exited the water.

[Howard Hughes]

When we carry people suffering from 'the bends' we fly them with a sea level cabin (aka 500ft). Not a medico but I am a diver and think 500ft (no higher) would only have a very minimal increase in risk!