entering the water. In-water procedures in this grouping include entry to the water, surface swimming, descent, buoyancy and trim control, equalisation of pressure in air spaces, maneuvering in midwater and at the bottom, monitoring the dive profile, gas supply and decompression obligations, normal ascent, and exit from the water. For some divers, gas switching, deployment of a decompression buoy and staged decompression may be added, or navigation under an overhead. Communications procedures depend on equipment and mode of diving, but are also in this group. After-dive maintenance and storage of equipment, debriefing, and logging the dive are also procedural parts of the normal diving operation. Clearing a flooded demand valve is both a routine procedure and an emergency procedure. It is an emergency procedure because if the DV is not cleared, the diver could aspirate water and choke, but it can easily happen, and will happen when a diver switches to a different gas supply delivered through a different DV, and there are two easy ways to deal with it, so it should not be a problem on a dive which runs according to plan. Routine scuba diving procedures (order may vary slightly, and some are also relevant to surface supplied diving, though details may vary): Selection of equipment – A diver is expected to be able select appropriate equipment and check it for fit and function. Preparation of equipment – Assembly and function checks of personal diving equipment Scuba assembly – Assembly and function check of the scuba set Site inspection and setup Kit-up/dressing in the diver - Dressing into the diving suit, breathing apparatus, harness and accessories Pre-dive checks - Check that all necessary equipment is correctly fitted and functioning Entering the water - Use of an appropriate water entry technique Surface checks - Final function checks and reports before descent. Breathing from the demand valve – The pattern of breathing can affect work of breathing and effective dead space, both of which must be limited, and preferably minimised. Mouthpieces must seal against the lips when used to prevent aspiration of water. Demand valve clearing – Expelling water from the interior of the demand valve. Descent – A generally consistent increase in depth until the operational depth is reached. Equalisation – Balancing pressures in air spaces with the ambient pressure. Equalise dry suit squeeze – Injecting sufficient gas into the dry suit for comfort and insulation Buoyancy control