taking unpressurized flights after diving

[lizardqueen]

I asked my Little Cayman dive operator if the non-pressurized flight we took from Grand Cayman "counted" like a regular commercial flight, as far as taking the prior day off from diving. The people at McCoys told me it affected you exactly the same way, since the puddle jumper was maybe 5,000 or 6,000 feet, and the cabin at 30,000 feet is pressurized to a similar altitude -- makes sense.

This topic has come up again in my post about Turks & Caicos :
http://www.scubaboard.com/forums/showthread.php?t=200409&page=2

My son & I did a 9-day combo trip back in late May. We took Sky King over to GT the first day and I monitored air pressure onboard the turboprop for use later...After 4 dive days on GT, we flew back to Provo in the afternoon, just a few hours after 2-tank diving. This is safe on Sky King due to low, yet pressurized flights. My hand-held altimeter gave me what I needed to know on the flight over.

So my question is whether there is ANY altitude you can fly at that's safe after diving, and if so what would that be, Dr. Deco & TheWizard?

 

[Gene_Hobbs]

So my question is whether there is ANY altitude you can fly at that's safe after diving, and if so what would that be, Dr. Deco & TheWizard?

We tried to summarize the available literature here. The tables on our page are fuzzy so please download the actual PDF of the referenced chapter in the US Navy Manual.

NOTE: This is by NO MEANS an exhaustive list. This is just some of the resources available online.

Bottom line is that it all comes down to your own concept of acceptable risk.

 

[Dr Deco]

Hi Liz:

It is necessary to check the surface interval tables for post-dive interval and altitude. Then it is safe for you. Gene has posted material [above].

Dr Deco

 

[lizardqueen]

thanks guys, I'll print a copy and put it in my dive bag...altitude doesn't come up much at sea level and I never thought about this being equivalent to flying before. Does someone make a plastic one like the the dive table they give you in OW?

 

[nereas]

I asked my Little Cayman dive operator if the non-pressurized flight we took from Grand Cayman "counted" like a regular commercial flight, as far as taking the prior day off from diving. The people at McCoys told me it affected you exactly the same way, since the puddle jumper was maybe 5,000 or 6,000 feet, and the cabin at 30,000 feet is pressurized to a similar altitude -- makes sense.

This topic has come up again in my post about Turks & Caicos :
http://www.scubaboard.com/forums/showthread.php?t=200409&page=2



So my question is whether there is ANY altitude you can fly at that's safe after diving, and if so what would that be, Dr. Deco & TheWizard?

The altitude and the time interval before going to altitude all depends on your USN (not PADI but USN) repetitive dive group. There is a table in the NOAA DIVING MANUAL that tells you how long you must wait to ascent to any altitude after diving, from 1000 ft to 10,000 ft.

So the answer is that you must check the table and wait the required time, anywhere from -0- to 48 hours, before ascending to ANY altitude above your dive site.

Gene's table, above, is a copy of it.

Be careful that you do not use PADI's dive groups by mistake. The groups must be USN.

The 48 hour requirement applies to any deco diving to 200 ft or deeper, per NOAA.

 

[Gene_Hobbs]

Gene's table, above, is a copy of it.

Since DAN and the Navy paid for our research to create the algorithm used for the tables (Both the Navy and NOAA), I am VERY careful NOT to call it a NOAA table.

Be careful that you do not use PADI's dive groups by mistake. The groups must be USN.

Good point, I would hope that is obvious but one never knows...

 

[nereas]

Nothing is ever obvious.

 

[Goose75]

Commercial aircraft are pressurized to a maximum altitude of 8000ft, at least until the Boeing 787 goes production. One of it's selling points is a lower pressure altitude.

 

[bleeb]

I posted a similar question just before the Great SB Crash of 2007.

I've heard somewhere that some of the 'flying after diving' recommendations are not based only on the 8000' cabin pressure in commercial passenger aircraft, but also on the 1 in x,000 flight where a window blows out at 35,000. A quick review of some of the papers Gene pointed to in the Rubicon repository didn't turn up anything.

Also, the O2 that planes carry in their 'if the mask should fall out of the ceiling' tanks is only meant to last the few minutes it takes for the pilots to get down to a breathable altitude. I've heard values from 8,000 to 12,000. Any pressurised cabin pilots out there know anything more exact?

 

[Gene_Hobbs]

A quick review of some of the papers Gene pointed to in the Rubicon repository didn't turn up anything.

And there's the rub in knowing what you heard and what really exists. This was also a MAJOR reason we started making this stuff available online rather than the initial plan for just getting the work done and to the researchers. The more time goes by, the better searches will come but this is not a full time job for any of us so please be patient.

The table we made for the navy (in it's last phase of control trials now) tested 8k and 25k. The 25k exposures were to cover High Altitude special operations jumps and included a 30 minute oxygen pre-breathe prior to the flight (as per Special Ops decompression protocol).

DECOMPRESSION RISK DURING HIGH ALTITUDE EXPOSURE AFTER DIVING
2002 UHMS abstract
RRR ID: 1168

If you really want to know about loss of cabin pressure, there are publications on those procedures and the physiology from the FAA and similar orgs.

As I stated before the crash, there is not anything that I am aware of on what would happen to a diver in that case but there are MANY more pressing issues at that time. There is some work on explosive decompression that may be of interest but I'll bet almost NONE of it will have residual gas loads prior to the exposure. This is Dr. Deco's area so he would know MUCH better than I.