How many hours is it?
Someone on the morning dive just saw a sea-horse. You would have time to make it for the afternoon dive, but you are flying out tomorrow morning. You want to go, you never saw the sea-horse and now its the last chance. Something in the back of your mind sets alarm bells off, and holds you back from the dive. How many hours do you need to wait before hitting the runaway, is it 12 hours, 18 hours….do you have enough time to dive?
PADI and DAN (Divers Alert Network)
These major organisations, both PADI and DAN suggest a fixed time limit before boarding an aircraft. If you have completed multiple dives, over multiple days with no decompression dives the recommended ‘no fly time and scuba diving’ is minimum 18 hours. The countdown starts when you exit the water. Minimum 18 hours must pass before you go and board your flight. This also applies to a dive trip on a live-aboard.
If you have completed only one no-decompression dive, you must wait at least 12 hours before you board the plane. It is crucial that you give yourself adequate time to off-gas the nitrogen that has built up in your body during your dives.
Nitrogen Bubbles and Pressure:
We all learnt in our Open Water course about flying after diving. The main concern here is decompression illness (DCS) or “the bends” due to a decreased ambient pressure in the cabin of the aircraft.
During your dive, the pressure increases as you dive deeper. Nitrogen is absorbed into your bloodstream and tissues from the air that you breath in proportion to the surrounding pressure. If you stay down at pressure, the absorbed nitrogen is not a problem. As you ascend, the built-up nitrogen comes out of your tissues into the bloodstream in the form of tiny wee bubbles. When we ascend slowly the tiny bubbles travel back to our lungs and will be eliminated each time we exhale. Upon reaching the surface, some of the nitrogen has been expelled back into the water, but quite a significant amount still remains in our body. If you fly directly after diving, the decreased ambient pressure will allow the residual nitrogen to come out of solution too quickly, causing large nitrogen bubbles to form in our bloodstream.
What Can Happen If I Fly Less Than The Recommend Time?
Flying to early after scuba diving can cause decompression sickness. This can range from joint pain all the way up to serious central nervous system problems and an untimely death. This is not always the case, but the risk is very high indeed. As cabin pressure drops slightly, nitrogen dissipates much quicker into the bloodstream. This may cause serious blockages of blood circulation and vital body functions.
Remember, you cannot call for a doctor or re-compression chamber if you begin to experience symptoms of “the bends” in mid-flight. On landing, your injuries may have become more severe and even life threatening.
Any reduction in surrounding pressure soon after your dive carries a heightened risk of DCS. Even driving up a mountain to higher altitude has the same risk as flying. A commercial flight on the ground has a cabin pressure equivalent of an altitude up to 2,134 m, as soon as the aircraft doors are sealed. This makes no difference if it is a large aircraft or a propeller machine. As you sit in the aircraft on the ground, your nitrogen bubbles may already begin to change due to a difference in surrounding pressure.
Be a Responsible Diver:
Make sure you leave 18 hours or more before you fly, better still 24 hours. Check the flying after diving laws of your destination country, they may vary. Make shallower dives towards the end of your vacation and stay hydrated before you fly.
Make sure you know how to read your computers flying after diving recommendations. No fly times and scuba diving must be adhered to. This is important as your computer has recorded and logged your diving profile.
Alcohol consumption can have a negative effect on nitrogen bubbles, so drink water instead.
As we all enjoy scuba diving, pick a great location and plan a safe vacation. No fly times are very important, especially if you dive multiple days throughout our vacation. Why not come and visit the beautiful Island of Gozo and enjoy our wonderful underwater world.
Dive Smart Gozo welcomes you to Gozo