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Both the UHMS and DAN agree that “There can never be a flying after diving rule that is
guaranteed to prevent decompression sickness completely. Rather, there can be a guide-
line that represents the best estimate for a conservative . . . surface interval for the vast
majority of divers. There will always be an occasional diver whose physiological makeup
or special diving circumstances will result in the bends”.
To reduce the risk of developing decompression sickness after a single no decompression
dive, current guidelines suggest waiting 12 hours prior to exposure to atmospheric pres-
sures equivalent to 1,000 feet (305 meters) above sea level, or greater.
When repetitive dives are conducted during the same day, or period of days, it is sug-
gested that the interval be increased to a minimum of 24 hours. Land travel to higher
elevations after diving must also be considered as an exposure to altitude.
Time to Fly is a basic countdown timer that begins counting down from 23:50 to 0:00
(hr:min) 10 minutes after surfacing from a dive.
TISSUE DESATURATION
Time to Desaturate (Desat Time) is a display of calculated time for tissue desaturation of
nitrogen at sea level taking into consideration the Conservation Factor setting. It also
begins counting down 10 minutes after surfacing from a dive, counting down from 23:50
(maximum) to 0:00 (hr:min).
(continued on page 28)
