Up until the 1.1.2 version DiveIno calculated an incorrect No Fly time. It was based on how much time must be spent on the surface to reach the commercial aircraft cabin pressure, which is about 0.8 bar. In other words 80% of the average surface pressure.
This is not the right way to calculate this important safety value! DAN reccomendations have to be followed! Besides that for maximum safety, tissue compartment desaturation times have to be taken in account as well.
Based on a DAN Medical Research the following was recommended:
For a single no-decompression dive, a minimum preflight surface interval of 12 hours is suggested. For dives requiring decompression stops, there is little evidence on which to base a recommendation and a preflight surface interval substantially longer than 18 hours appears prudent.
Later this recommendation was refined a bit by DAN Europe and this is the current status:
The current position is: wait AT LEAST 12 hours after a single No Decompression Dive and 24 hours after repetitive, multiple day or decompression diving.
In order to be able to fully interpret this recommendation, the following definitions have to be understood:
Repetitive dive: The end of the previous dive was within 24 hours of the start of the current dive.
No Decompression dive: There was no decompression stop calculated during the dive.
Desaturation time: The maximum time until each compartment partial pressure returns back to the initial value adjusted by a given percentage.
Some low percentage value - around 2% - must be used in desaturation time calculation to define a desaturation threshold. Thanks to half times based pressure reduction; in theory the compartment will never reach its initial partial pressure just converge to it. When the compartment partial pressure reaches this pre-defined threshold, it can be considered as desaturated.
The compartment desaturation time can be longer that the DAN recommended 12 or 24 hours. For maximum safety this must be the No Fly time, when it happens. DiveIno calculates No Fly time based on these rules:
Non-repetitive AND No Decompression dive:
- Desaturation time > 12 hours => No Fly time = Desaturation time
- Desaturation time <= 12 hours => No Fly time = 12 hours
Repetitive OR Decompression dive:
- Desaturation time > 24 hours => No Fly time = Desaturation time
- Desaturation time <= 24 hours => No Fly time = 24 hours
After 48 hours all compartments considered to be desaturated.
DiveIno displays No Fly time after the dive and on the Surface Time screen: