Hypothetical Question: Altitude Diving and Flying

[in_cavediver]

Here's a simple question: If you do a properly planned dive at an elevation of 8000', do you have to wait XX hours prior to flying. (Insert 12, 24 etc for XX)? I would guess no since the airplane cabin is pressured to at least 8000' feet.

Opinions?

 

[BigJetDriver]

There are some other factors. For instance, your surface altitude for beginning your dive is 8000 ft msl, in this case, but what is your equivalent dive depth and time? Remember, that "Time to Fly" is based on nitrogen dosage, as well as ambient pressure.

Also, can you get on the aircraft at 8000 ft? If not, you may be "atmosphere diving" as you descend to get on the plane.

 

[in_cavediver]

Your surface altitude for beginning your dive is 8000 ft msl, in this case, but what is your equivalent dive depth and time? Remember, that "Time to Fly" is based on nitrogen dosage, as well as ambient pressure.

Insert any properly completed rec dive. (IE, no values above the M0 for 8000')

 

[BigJetDriver]

Assuming that, and that you can get on the plane at 8000 ft, I would have to say the answer is "no" as well since, by definition your dive allows you to go direct to the surface safely (surface here being 8000 ft).

As a side note, we were at 40,000 ft msl aircraft altitude day before yesterday, and the cabin altitude was 7,200 ft msl.

 

[Whatgoesdown]

Assuming that the pressure will go no lower, you shouldn't have to wait. If DCI cases have to be evacuated at sea level, the plane/helicopter is supposed to fly at less than 300m/1000' to avoid decompressing the patient further. Do you know of a dive site at 8000' with a commercial airport close by?

 

[in_cavediver]

Assuming that the pressure will go no lower, you shouldn't have to wait. If DCI cases have to be evacuated at sea level, the plane/helicopter is supposed to fly at less than 300m/1000' to avoid decompressing the patient further. Do you know of a dive site at 8000' with a commercial airport close by?

Nope, just was talking to another diver and discussing this and thought i'd share it in case there was something i'd missed.

 

[String]

Id be more concerned about what happens if the plane depressurises at altitude than anything else. Even for dives at sea level etc with a proper interval. Granted its a very unlikely situation to be in but that drop from 5000ft or so cabin altitude to 30,000ft in 60 seconds may cause issues even for a person obeying theoretical no fly limits

 

[Whatgoesdown]

It'll be a problem for everyone! Even the non-divers!

 

[boulderjohn]

I asked this same question to DAN last year, along with a related question about driving over mountain passes. I also asked about low level flights.

The response was that they defined "flying" after diving as an increase of altitude more than 2000 feet.

They specifically said a diver would be able to fly after diving at 8,000 feet, since there is not an increase in altitude greater than 2,000 feet.

Of course, that assumes the plane stays pressurized.

 

[roakey]

Here's a simple question: If you do a properly planned dive at an elevation of 8000', do you have to wait XX hours prior to flying. (Insert 12, 24 etc for XX)? I would guess no since the airplane cabin is pressured to at least 8000' feet.

Techincally it's NOT the same thing. I live at about 8000 feet. If I jump into a nearby mudpuddle, at the start of the dive my N2 loading is at equalibrium at 8000 feet (call it about 0.75ATA sea level), which means I start the dive with less N2 in my tissues than I would have at sea level. When I finish the dive, I surface to .75ATA, which means I outgas faster than I would at sea level (which is part of the reason for the altitude tables).

If I do a dive at sea level, I start with more N2 in my tissues, when I surface I outgas slower at sea level, so even if I used the 8000 foot tables to perform my dive, I will get on the plane with a higher N2 loading than if I had actually performed the dive at 8000 feet.

Does this make an actual difference? Who knows -- get DAN insurance, try it and tell us how it goes

Roak