where is the Indication of "No fly" ?

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Gepetto
Posts: 5
Joined: Saturday 11. July 2020, 22:29

where is the Indication of "No fly" ?

Post by Gepetto »

OSTC Plus, 3.20 release.
Where is the indiction of "no fly" on the surface screen ?
I dived today, I have the "desaturated time" is showed but not the "no fly time" Is it the same ?
Thanks for your help
regards
Gérard
Motardplongeur
Posts: 56
Joined: Thursday 13. August 2015, 19:24

Re: where is the Indication of "No fly" ?

Post by Motardplongeur »

The "no fly" is just above the "Desat" time, at least on the screen "desaturation" (w/ tissue diagram)

Maybe you did not reach the min value of saturation to warn for a no fly duration.

General question : how is calculated this "no fly" in the SW ?
Les pieds dans l'eau, la tête dans les étoiles, le reste sur terre !

OSTC #12002 & #11150
Ralph
Posts: 708
Joined: Saturday 24. June 2017, 11:31

Re: where is the Indication of "No fly" ?

Post by Ralph »

The "no fly" time is calculated like a deco stop, with the current surface pressure as the current "depth" and a pressure of 0.6 bar as the target "surface" pressure. Thus, the "no fly" time is the time one has to "stop" at the current surface pressure until the tissue have desaturated enough to allow for an ascent to an altitude that equals 0.6 bar in pressure. It is done using the normal Bühlmann equations and coefficients, just in the diving at altitude range.
Gepetto
Posts: 5
Joined: Saturday 11. July 2020, 22:29

Re: where is the Indication of "No fly" ?

Post by Gepetto »

Thanks for your answers,
But I'm surprised, Sunday evening, I had 18h of "desat" but no "nofly" ??
Next week I will dive a lot, so , I will check more carefully.
Ralph
Posts: 708
Joined: Saturday 24. June 2017, 11:31

Re: where is the Indication of "No fly" ?

Post by Ralph »

That's normal. "Desat" has a target pressure of 105% of the surface pressure (= 5% overpressure) for every tissue, that's a much lower value than what the tissues will be able to stand at 0.6 bar. This is not to say everyone should board an aircraft right after diving, but this "take some time after diving before flying" rule is more due to DCS often developing in deferred time, and once airborne theatment is much more difficult than down at earth.
The 'no fly' and the '1000m', '2000m' and '3000m' waiting times are to be understood as hard limits. On the other hand, they will give "emergency go possible" time indications in case a site has to be evacuated e.g. due to an emergency. When doing so, DCS risk at the edge of the 'no time' is the same as with a regular deco dive - beware that the 'no time' calculations are always done with a GF of 100% !
Gepetto
Posts: 5
Joined: Saturday 11. July 2020, 22:29

Re: where is the Indication of "No fly" ?

Post by Gepetto »

It is clear
Thanks
Motardplongeur
Posts: 56
Joined: Thursday 13. August 2015, 19:24

Re: where is the Indication of "No fly" ?

Post by Motardplongeur »

Thanks Ralph; crystal clear.
Les pieds dans l'eau, la tête dans les étoiles, le reste sur terre !

OSTC #12002 & #11150
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