1. Buddy System Violations
If you’re separated from your dive buddy, look around for the agreed upon amount of time (you decide this with your buddy before the dive), and then start making your way to the surface. If you both follow the same plan, you should reunite underwater or on the surface and can continue the dive. Many dive incidents occur when a buddy team separated and made no effort to reunite.
2. Not Enough Air, Not Paying Attention to Air, Staying Beyond Minimum Ascent Pressure
Always start your dive with a full tank, and make sure you dive your plan. If the dive plan states that the dive is over at 1000 PSI, start ascending to your safety stop at 1000 PSI. Many dive incident reports show that divers overstayed their dive, even though they were knowingly low on air.
3. Weighting and Buoyancy Issues
Diving improperly weighted is a common way to have buoyancy problems, which can lead to either a rapid ascent, or bouncing off the bottom and provoking a defense mechanism from a creature who lives there. Remember your training, and always try to be neutrally buoyant in your Zen position, using your breath rather than your BCD to control your place in the water column.
4. Reckless Judgment
Always make the prudent choice in underwater decisions. Nitrogen Narcosis is a condition about which we still know very little. While it generally kicks in around 99 feet, Nitrogen can still affect your decision making process. Always remind yourself to make the cautious choice while diving. Also, starting a dive with malfunctioning equipment such as a nonworking SPG, or a dry suit dive without a low-pressure inflator hose can have disastrous results.