shallow-dive wait-time before flying

[seeker242]

The US Navy diving manual has a SI/Altitude table. It lists every group with every altitude up to 10,000 and the SI times. According to the Navy air table, the max group you can reach at 20 fsw, regardless of bottom time, is C. For group C, at 8,000 ft, the SI before flying is none. But, the Navy is not known for being conservative.

 

[Lorenzoid]

The US Navy diving manual has a SI/Altitude table. It lists every group with every altitude up to 10,000 and the SI times. According to the Navy air table, the max group you can reach at 20 fsw, regardless of bottom time, is C. For group C, at 8,000 ft, the SI before flying is none. But, the Navy is not known for being conservative.

If I'm looking at the same table you are, it indicates a surface interval of 0:00 for a diver in Group C to ascend to 8,000 feet, but a surface interval of 3:06 for a diver in Group C to ascend to 9,000 feet, and a surface interval of 8:26 for a diver in Group C to ascend to 10,000 feet. Those seem like quite substantial differences in SI for each additional 1,000 feet. It also says the table "may only be used when the maximum altitude achieved is 10,000 feet or less." If, as someone mentioned, the cabin were to lose pressure ....

 

[redacted]

And you actually expect educated and reasonable people who are experts in this matter will just set aside the safety rules and lawyers advice and all experts' statements and give you advice that go against all that????????????????

A difference between a knowledgeable person and a parrot is the parrot can not interpolate or extrapolate his knowledge.

 

[DevonDiver]

A difference between a knowledgeable person and a parrot is the parrot can not interpolate or extrapolate his knowledge.

What 'knowledge'?

Knowledge of the DAN flying after diving recommendations?

Knowledge of tests and studies examining flying after shallow diving?

Or are we talking about a deliberate interpretation of diving tables in a context for which they weren't designed or intended, whilst simultaneously ignoring the tables-linked recommendations specifically included to deal with flying after diving?

 

[seeker242]

If I'm looking at the same table you are, it indicates a surface interval of 0:00 for a diver in Group C to ascend to 8,000 feet, but a surface interval of 3:06 for a diver in Group C to ascend to 9,000 feet, and a surface interval of 8:26 for a diver in Group C to ascend to 10,000 feet. Those seem like quite substantial differences in SI for each additional 1,000 feet. It also says the table "may only be used when the maximum altitude achieved is 10,000 feet or less." If, as someone mentioned, the cabin were to lose pressure ....

Think that might be a different version table? This is the one I was looking at. It's the full manual so it's a large PDF. http://www.usu.edu/scuba/navy_manual6.pdf#Chapter9.indd:Table 9-6

Given those numbers, it would seem an 8 hr SI isn't really that bad. Especially when, according to the air table, it will take 7 hours at 20 fsw just to get into group B. But yea, I don't know if that accounts for loss of cabin pressure. Do the DAN numbers account for loss of cabin pressure?

 

[oldschoolto]

Cabin pressure on MOST aircraft is in the 6,000' to 8,000' ASL... I don't know what the body would do if it was subjected to a rapid decompression to 30,000' - 35,000' ASL... The pilot would start a rapid decent to 6,000' ASL at a rate of 4,500' to 5,500' FPM... So your looking at about 5 minutes for gas bubbles to start forming... And that from the time the pilot starts the descent...

Jim....

 

[Scuba J7]

Without looking, pretty sure DAN recommends total gas washout before flying. At least theoretical total washout.

Do the DAN numbers account for loss of cabin pressure?

 

[diver0008]

I am a fairly conservative recreational diver. My computer always shows me a no-fly time after diving. I am under the impression that most dive computers provide this information. Could the OP in this topic not rely on the information his computer provides?

 

[redacted]

What 'knowledge'?

Knowledge of the DAN flying after diving recommendations?

Knowledge of tests and studies examining flying after shallow diving?

Or are we talking about a deliberate interpretation of diving tables in a context for which they weren't designed or intended, whilst simultaneously ignoring the tables-linked recommendations specifically included to deal with flying after diving?

D: None of the above.

Answer:. Based on proven decompression model(s), determine the time to desaturation for the proposed dive. Use that as a possible no-fly time.

 

[tursiops]

I am a fairly conservative recreational diver. My computer always shows me a no-fly time after diving. I am under the impression that most dive computers provide this information. Could the OP in this topic not rely on the information his computer provides?

Some show a DESAT time, meaning the slowest compartments in the model have emptied out. Some show a TIME BEFORE FLY, which may be either a DESAT time or a simple 24h clock. Some show both.

The issue is, it is not your computer that is going to get a DCS hit. So, yes, the DESAT time is interesting info, but not worth trusting a life on crutches to.