Suunto D4 User Manual page 47

WHEN CEILING AND STOP ARE
DISPLAYED, MAKE A ONE MINUTE
MANDATORY SAFETY STOP IN THE
DEPTH ZONE BETWEEN 6 M AND 3 M.
You must not ascend shallower than 3 m/10 ft with the Mandatory Safety Stop warning
on. If you ascend above the Mandatory Safety Stop ceiling, a downward pointing arrow
will appear and a continuous beeping starts. You should immediately descend to, or
below, the Mandatory Safety Stop ceiling depth. If you correct this situation at any
time during the dive, there are no effects on the decompression calculations for future
dives.
WHEN CEILING AND STOP
ARE DISPLAYED, IMMEDIATELY
(WITHIN 3 MINUTES) DESCEND
TO OR BELOW CEILING.
If you continue to violate the Mandatory Safety Stop, the tissue calculation model is
affected and the dive computer shortens the available no-decompression time for your
next dive. In this situation, it is recommended that you prolong your surface interval
time before your next dive.
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