Flying vs Flying

[DawgPaddle]

Hello Again,

First of all, Thanks Soooo Much for all the reply's so far. I'm still new to the SCUBA world but am already realizing the genuine concern that divers have for the sport. Good Wood!!!!

My question:

I've learned that depending on the lenght and depth of the dive, "one" shouldn't fly for approx. 24 hours after a dive. Well, can anyone define "FLY". My reasoning is - I'm a pilot and have been day dreaming about flying down to Cape May or the shores of North Carolina to dive let's say on a Saturday and flying back Sunday Morning. The aircraft that I fly are Cessna and Cherokee types that are not pressurized. I generally fly between 4000-6000 feet so does the no-fly-for-24-hour rule apply here? Perhaps No Flying means just that, but I wanted to verify if "flying" was indicative of pressurized aircraft or not. If I were to fly from just outside of Philly to Cape May or Long Beach Island, I could do it reaslistically below 3000 feet the whole way. Do I need to drive a 4 wheeler (car) or can I fly down and scuba dive like a wild hippopotomus and fly back that afternoon or the following morning.

Again, thanks for your help thus far. I probably have about 1322 more questions to go.

DawgPaddle

 

[AllenG]

Flying in an unpressurized cabin means that you are indeed under experiencing less than 1 atmosphere of pressure when you are up in the air. This sounds like a recipe for disaster!

 

[Drew Sailbum]

The concern with flying after diving is that when you hit the surface and the dive is over, you will continue to offgas accumulated nitrogen for some time. If you ascend to altitude (and we're really talking about experiencing a rapid reduction of atmospheric pressure which is associated with flying), you increase the rate of offgassing. If that rate of offgassing is too high, you may get Decompression Sickness (DCS).

Most commercial aircraft are pressurized to the atmospheric pressure at about 8000ft altitude. :fly: Smaller craft usually fly lower, but are usually not pressurized.

Decompression theory comes into play, and the key word is theory. There is a lot of art to this science, and no guarantees even if you follow all of the rules and tables. But it seems that flying a Cherokee at 4000ft would be a bad place to be if DCS hits. :dead:

The PADI RDP is perhaps the most extensively tested dive table for recreational diving, and it permits an ascent to 1000ft immediately following diving with no special procedures. Above that, and you should consider having some additional offgassing time before hopping in the pilot's seat. The amount of time should be in some proportion to the length and depth of your diving, but I can't give exact recommendations.

To better understand the concerns involved, I suggest taking a speciality course in altitude diving. Special concerns arising out of ascending to altitude apply to ascents by car or plane. You will have to decide what level of risk you are comfortable with.

 

[Rick Murchison]

Hi there,
By way of introduction, I'm a CFI (since '67) and a diving instructor. Your question is a good one, and has, as you might expect, a bit of a complicated answer.
For airliners, with a cabin altitude of 8,000' the answer from DAN is that you should wait at least 12 hours after a single dive, and at least 17 hours after multiple dives or after multiple days diving, and 24 hours or more if possible.
For your specific question, I'll refer you to the NOAA ascent to altitude after diving tables, which are based on the Navy tables. For example, if your highest Navy table group designator in the 24 hours measured back from the completion of your last dive is "H" (a 60' dive for 48 minutes will do that), then for a flight not exceeding 6,000' you should wait at least 8 hours and 5 minutes before taking off. If you're going to an airliner under the same circumstances the NOAA table calls for a 14 hour 9 minute wait. If you keep it to 3,000 MSL then your wait need only be an hour and 31 minutes. But in your part of the country you'd best be prepared for the worst ATC can dish out, don'tchathink?
The table is on page 4-28 of the new NOAA diving manual, a book I highly recommend for all divers.
Rick

 

[DawgPaddle]

Originally posted by Rick Murchison
Hi there,
By way of introduction, I'm a CFI (since '67) and a diving instructor. Your question is a good one, and has, as you might expect, a bit of a complicated answer.
For airliners, with a cabin altitude of 8,000' the answer from DAN is that you should wait at least 12 hours after a single dive, and at least 17 hours after multiple dives or after multiple days diving, and 24 hours or more if possible.
For your specific question, I'll refer you to the NOAA ascent to altitude after diving tables, which are based on the Navy tables. For example, if your highest Navy table group designator in the 24 hours measured back from the completion of your last dive is "H" (a 60' dive for 48 minutes will do that), then for a flight not exceeding 6,000' you should wait at least 8 hours and 5 minutes before taking off. If you're going to an airliner under the same circumstances the NOAA table calls for a 14 hour 9 minute wait. If you keep it to 3,000 MSL then your wait need only be an hour and 31 minutes. But in your part of the country you'd best be prepared for the worst ATC can dish out, don'tchathink?
The table is on page 4-28 of the new NOAA diving manual, a book I highly recommend for all divers.
Rick

Rick, Thanks for a great explanation. I immediately grabbed my dive table and pretty much followed along as I read your reply. I've always heard if folks like to fly, they'd love to dive and it seems at this point that it's quite true. Thanks again....Oh, ref the ATC in this area - you bet it can be crowded on freq and in the air many times up here. I controlled in the Air Force for 15 years and kinda learned from experience how to get the "short-cuts"...Ciao

ilot:

 

[DennisW]

Rick,

Thanks much for the explaination. I guess I should get that NOAA dive manual. I am also a pilot, but I have never (at least not yet) flown to a dive site and back. Until just recently I lived in Floriday and drove. Now that I live in Newport News, VA. I'll be wanting to fly to FL, NC, etc. for some dive trips. I nearly flew to Venice Beach, FL and dove once, but opted for the 3.5 hour drive from Melbourne, FL instead because I wasn't sure about the issue. My wife is a CFII and will be interested to know this bit of information.

 

[Drew Sailbum]

To clarify one point, flying to the dive site and diving is not a problem. Unless you are doing something odd, like flying to a lake at high altitude(coastal Peru to Lake Titicaca), there is no reason you can't dive immediately after landing.

The problem is ascending to altitude after diving. So long as you don't mind the wait to go home (which may require an overnight), you can certainly fly to dive sites.

 

[DameDykker]

Very interesting!

My SO is a pilot with his own plane. So we talked about something like this. Where do I get those tables??


Pia

 

[Ari]

at www.vnh.org and search for the US Navy Diving Manual.

It is a great document to download anyway (a *.pdf format).

It also relates to diving above sea level and flying after diving.

Enjoy reading.

Ari

 

[Rick Murchison]

Originally posted by DameDykker
Where do I get those tables??

NOAA diving manual.
Available online from Best Publishing or Barnes & Noble
Rick