What's the maximum no fly time?

[boulderjohn]

Europe - Flying after Diving

My mistake, the 18 hours is not implemented yet, so officially the 24 hour recommendation for max is still in place.

DAN America and DAN Europe do not agree.

DAN Europe recently did a maddening study to see if their 24 hour requirement was sufficient. (Pay close attention to that word.) They used Doppler bubble imaging to check divers 24 hours after diving, and found they were all clear and good to go. They therefore proclaimed that it proved that the 24 hour period was sufficient.

They did not test them at 12 hours. They did not test them at 18 hours. Thus, although we do know that 24 hours is suficient, we do not know if it is necessary.

DAN America still goes with 18 hours after multiple dives.

 

[Anna1990]

Interesting discussion. This is just standard vacation diving, no square profiles or deco expected although I did forget that we've booked an enriched air course so we'll be using nitrox for the first time.

 

[yle]

I've used my trusty Suunto D4 for many years, including many multi-day dive trips. I have managed to push its no-fly time to 25 hours... but I was working pretty hard to do that: several days in a row with 4 dives a day, and at least one dive each day deeper than 100 ft.

I would bet your D4 will get up to 22, 23 or maybe even 24 hrs with the three dives per day you've described. But I would be very surprised, based on what I've observed of my own D4, if yours went beyond 24 hrs.

 

[Lorenzoid]

. . .
DAN America still goes with 18 hours after multiple dives.

Alert Diver did add that "the 18-hour interval may deserve another look." I guess we will await a further study. Or just go with 24 hours to err on the side of caution.

 

[CWK]

Photo of my Suunto taken this morning. Last dive was yesterday.

 

[CWK]

You may also want to read
https://dipot.ulb.ac.be/dspace/bitstream/2013/199711/3/CialoniFlyingafterdivingDHM2015.pdf

 

[RainPilot]

View attachment 469075 Photo of my Suunto taken this morning. Last dive was yesterday.

Goodness me. Could you give an indication of the dives that lead to that? I know its a pain but just a general idea. I know Suunto are supposed to be very conservative as per internet wisdom but a 28 hour no-fly is... intriguing to me. That was after 19 hrs of SI, did it give you 48 hours on surfacing?

ETA: I notice SI plus No-fly is exactly 48 hours, I wonder if that isn't a conservancy setting or maybe a response to a violation of some kind? I know Suunto are very quick to punish even momentary ascent violations etc. I seem to recall a 48 hour penalty of some kind, I'll need to look it up.

ETAM: Seems like the 48 hours is a violation response or a dive mode issue, usually:
#4

 

[CWK]

FWIW, Buhlmann compartments 1-10 will completely clear within 14 1/2 hours, with 11-12 clearing completely by 24. The remaining four might take longer, but even on a liveaboard trip doing 27 dives in 5 1/2 days I've never seen those accumulate any significant amount of inert gas.

I once turned on my Perdix whilst on a commercial flight. It was set to 21% and the PPO2 was showing 0.10 if I recall correctly. A commercial airline cabin has to be pressurised to at least 0.5ATA or the PPO2 may be too low to sustain life. Assuming that the slowest compartment is the leading compartment and is fully supersaturated after the last dive, the N2 half time of the slowest compartment may be used to determine the no fly before flying to 0.5ATA. I believe that this would indicate a no fly of about 11 hours and it assumes that the plane does not suffer depressurisation.

Personally, I’m happy to stick with 24 hrs and have flown with some residual N2 in the slower compartments.

 

[CWK]

Goodness me. Could you give an indication of the dives that lead to that? I know its a pain but just a general idea. I know Suunto are supposed to be very conservative as per internet wisdom but a 28 hour no-fly is... intriguing to me. That was after 19 hrs of SI, did it give you 48 hours on surfacing?

ETA: I notice SI plus No-fly is exactly 48 hours, I wonder if that isn't a conservancy setting or maybe a response to a violation of some kind? I know Suunto are very quick to punish even momentary ascent violations etc. I seem to recall a 48 hour penalty of some kind, I'll need to look it up.

ETAM: Seems like the 48 hours is a violation response or a dive mode issue, usually:
#4

No violations of any sort. It was, and still is. set to guage mode. I was using it to monitor run times whilst doing decompression diving.

 

[RainPilot]

I once turned on my Perdix whilst on a commercial flight. It was set to 21% and the PPO2 was showing 0.10 if I recall correctly. A commercial airline cabin has to be pressurised to at least 0.5ATA or the PPO2 may be too low to sustain life. Assuming that the slowest compartment is the leading compartment and is fully supersaturated after the last dive, the N2 half time of the slowest compartment may be used to determine the no fly before flying to 0.5ATA. I believe that this would indicate a no fly of about 11 hours and it assumes that the plane does not suffer depressurisation.

Personally, I’m happy to stick with 24 hrs and have flown with some residual N2 in the slower compartments.

I have used mine in flight, I got PPO2 of 0.16 and 0.17

0.10 is too low for consciousness, hypoxia would be the result. I had clear tissues on mine, it was very interesting to see how the tissue graph loaded like crazy at first and then off gassed through the flight. Im waiting for an opportunity to take one that has been dived hard that day up and see what happens.