Flying after 20ft dive

[Gage Wenger]

There are NAVY Altitude table to be able to see how long you need after how long and how deep of a dive you did. Very helpful when I go skiing the same day as I dive. Just google NAVY Altitude tables.

 

[caruso]

I have to admit I don't understand why diving altitude NDLs makes a difference.

Because those numbers are more conservative, given that they are accounting for the thinner atmospheric air. It's just another way of building in a safety margin. Sort of like setting your computer for a lower blend of Nitrox than you're actually diving (doing that builds an NDL cushion but will have the opposite effect ton the computers calculation of the P02).

 

[Jcp2]

Without making any recommendations, I note that the OP's question is partially answered on pages 25 and 26, but also recommend reading the entire workshop proceedings.

https://www.diversalertnetwork.org/files/FADWkshpBook_web.pdf

 

[tursiops]

by the rdp, you are washed out after 6 hours if you don't venture deeper than 30 ft. with a rich nitrox mix like ean40 or above, probably safe enough.

You are washed out at sea level, not 8000 ft altitude (cabin altitude).

 

[runsongas]

You are washed out at sea level, not 8000 ft altitude (cabin altitude).

padi rdp does not exceed 6 hours on the SI to leave group A for any NDL dive

 

[Seaweed Doc]

I'm just gonna throw it out there for thought regarding breathing high O2 mixes to avoid Nitrogen ongassing, even though unlikely...

Oxygen bends... you are still ongassing at depth



ps, I'd still fly, you shouldn't

I think oxygen offgassing isn't as big a concern because you metabolize it. That is, you're not just relying on reaching an equilbrium with the pp of O2 in the air, but your cells are converting the oxygen to water all the time. Nitrogen is biologically inert in us, so you're strictly relying on offgassing. Put another way, oxygen should reach equilibrium with the atmosphere much more rapidly than nitrogen will.

That said, I'd wait the extra day. Enjoy an extra afternoon of diving.

 

[Schwob]

You are washed out at sea level, not 8000 ft altitude (cabin altitude).

30,000 ft in case you are exposed to depressurised cabin altitude... I think the margins are supposed to be for that, not just 8k ft.

 

[JackD342]

padi rdp does not exceed 6 hours on the SI to leave group A for any NDL dive

I am not sure what point you are making, or what point of view you are supporting or disputing.

But.... if you are equating the RDP "washout" at 6 hours with "okay to fly," that is not what the RDP is saying. The RDP "time to fly" guidelines are on the other side of the slate, and I believe they currently say something like "1 dive & 1 day, wait 12 hours. Multiple dives and/or multiple days, wait minimum 18 hours."
I think that is at least the 3rd iteration of RDP flying after diving guidelines over the years.

After the 6 hour wait on the RDP there is not enough RNT to include the calculation for your next dive, but that is not the same as cleared to fly.

 

[EireDiver606]

Short version: a 20 ft dive (unless it’s extremely long and working underwater) is fine to go flying a few hours after.

Personally, after a full holiday, I wouldn’t dive 24 hrs before a flight but that’s because it’s deeper and high volume. And in some circumstances, some people feel dcs when others don’t so take the Do dive Don’t dive thing with a grain of salt.