A&D 2 Plus - Manual (Page 5)

SURFACE MODE
Note: Surface Mode will stay visible for 3 minutes.
After that, the screen will go blank to save battery
power. To reactivate the Surface Mode display,
touch contacts A&D.
SURFACE MODE ICON
Five minutes after surfacing, the M2+ enters
Surface Mode. While in Surface Mode, the
Surface Mode Icon appears at the top of the
display.
Surface Mode Icon
WAIT-TO-FLY TIME
Wait-to-fly time is the minimum amount of
time you should wait before flying in a
commercial airliner. Wait-to-fly time is
displayed in hours and is denoted by the no-fly
icon immediately below it.
WARNING: Flying while the M2+ is
still displaying wait-to-fly time may
lead to serious injury or death from
decompression sickness.
Wait-to-fly Recommendations
The Divers Alert Network (DAN) has made
the following recommendations regarding
wait-to-fly time:
Wait-to-fly time
display
1. A minimum surface interval of 12 hours would be required in
order to be reasonably assured a diver will remain symptom free
upon ascent to altitude in a commercial jetliner (altitude up to
8000 ft/2400 m).
2. Divers who plan to make daily, multiple dives for several days,
or make dives that require decompression stops should take
special precautions and wait for an extended surface interval
beyond 12 hours before flight.
Both the Undersea and Hyperbaric Medical Society (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
guideline 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."
U.S. Divers recommends that you follow either the DAN recommen-
dation, or the wait-to-fly time shown by the M2+, which ever is
longer.
DESATURATION TIME
Desaturation time is the amount of time it
takes to completely off-gas any residual
nitrogen in your system. Desaturation time is
displayed in hours and minutes.
SURFACE INTERVAL TIME
Surface interval time is shown immediately
after accessing Memory Mode. For more
information on accessing Memory Mode, see
page xx.
Desaturation time
MICROBUBBLE WARNING
Repetitive diving may cause microbubbles to
accumulate in the lungs if the surface
interval between dives is not long enough.
Ignoring decompression stops or an excessive
ascent rate can also lead to bubble formation.
In order to reduce the risk of decompression
sickness for future repetitive dives, the
surface interval should be planned long
enough to reduce the risk of decompression
sickness. If the M2+ calculates that the
formation of microbubbles may occur during
the surface interval, it will advise the diver
to extend the surface interval. The display
“Atn” (= attention) is visible in the depth
display area during the surface mode. While
“Atn” is displayed, the diver should not
undertake another dive.
Note: If a dive has to be made while “Atn” is
displayed, the amount of “Atn”-time for the
following dive can increase considerably.
During the dive, no-stop times will be much
shorter and decompression times will increase.
Microbubble
formation warning
Atn = Attention
DIVING AT ALTITUDE
The M2+ measures the atmospheric pressure
even while in Sleep Mode. If the computer
detects a higher altitude, it automatically
switches on and displays the adaptation time.
This is the time after which your body is
considered desaturated and stable at the
given altitude.
ALTITUDE SECTORS
Atmospheric pressure is influenced by altitude
and weather. The M2+ is interested only in the
actual atmospheric pressure value for use in
decompression calculations. However, it
indicates the altitude sector which corresponds
most closely with this pressure for normal
weather conditions. The altitude sectors and
their corresponding altitude is illustrated
below.
Altitude adaptation
time display
Adt=Adapt
switches at
switches at
switches at
switches
Even the smallest differences in the pressure sensors can cause two
computers at the same altitude to display different altitude sectors.
(Notice how the altitude sectors overlap in the illustration.) These
differences are not meaningful and do not interfere with the
operation of the computer. However, if there is an altitude indication
while at sea level, or two computers differ by 2 altitude sectors,
contact your U.S. Divers dealer for service.
Note: In order to assure optimal decompression even at higher altitudes,
the 10-foot decompression stop is divided into a 13-foot stop and 7-foot
stop. Therefore, the prescribed decompression stops, in order, are 7 ft,
13 ft, 20 ft, 30 ft ... 80 ft.