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Decompression Sickness and Scuba Diving: What Pilots Need to Know

If you’ve ever spent a day under the waves scuba diving and then jumped into an airplane shortly after, you may have unknowingly been playing with a potentially serious hazard: Decompression Sickness (DCS). While diving and flying are both incredible experiences, combining them without proper planning can lead to medical emergencies — sometimes even at altitudes well below typical cruising levels.


In this article, we’ll explore what decompression sickness is, why it’s a concern for aviators after diving, and the FAA’s recommended wait times before flying.



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What is Decompression Sickness?

Decompression Sickness, also called “the bends,” occurs when dissolved inert gases — primarily nitrogen — come out of solution in your body’s tissues and form bubbles.

Here’s how it works:

  • At sea level, your body’s tissues absorb nitrogen from the air you breathe.

  • When scuba diving, the water pressure increases, forcing more nitrogen into your bloodstream and tissues.

  • If you return to a lower-pressure environment too quickly, the nitrogen doesn’t have time to safely off-gas. Instead, it forms bubbles, much like opening a soda can too fast.


These nitrogen bubbles can cause symptoms ranging from joint pain and fatigue to neurological damage or even death in severe cases.


Why Flying After Diving Is Risky

Flying is essentially another form of decompression. Even if you’re flying in a pressurized cabin, cabin altitude is typically maintained at 6,000–8,000 feet — a lower pressure than sea level. If you’ve recently been diving, that extra reduction in ambient pressure can trigger or worsen DCS.


Key Points:

  • Scuba diving loads your body with excess nitrogen.

  • Flying after diving adds more decompression stress.

  • The higher (or less pressurized) you fly, the greater the risk.


Symptoms of DCS

A pilot who develops DCS after diving and flying might experience:

  • Joint and limb pain (“the bends”)

  • Dizziness or vertigo

  • Numbness or tingling

  • Confusion or difficulty thinking

  • Extreme fatigue

  • Skin rash or mottling


These can develop during flight or several hours afterward. In aviation, this is particularly dangerous because it can impair judgment and physical coordination at a critical time.


FAA and Diving Medicine Recommendations

Both the FAA Civil Aerospace Medical Institute (CAMI) and the Divers Alert Network (DAN) provide guidance for pilots. The recommendations are based on the type of dive and whether decompression stops were required.


Minimum Surface Interval Before Flying:

  1. After a single no-decompression dive: Wait at least 12 hours before flying.

  2. After multiple dives or dives requiring decompression stops: Wait at least 24 hours before flying.


These times are minimums, assuming the diver has had no symptoms of DCS. More conservative wait times — such as 24 hours after any diving activity — are considered safest.


Special Considerations for Pilots

Unlike recreational travelers, pilots have additional safety responsibilities:

  • You may be exposed to higher altitudes in unpressurized aircraft or with less regulated cabin pressure than an airliner.

  • Any impairment from DCS can directly affect flight safety.

  • If you’re diving on a layover or before a planned flight, ensure your co-pilot and operator are aware of your activities.


Pro Tip: The safest practice is to dive after your flying, not before.


In-Flight Emergencies

If symptoms of DCS appear in flight:

  1. Descend to the lowest safe altitude (ideally near sea level pressure).

  2. Administer 100% oxygen to help wash nitrogen out of the body.

  3. Land as soon as practical and seek emergency medical care. Hyperbaric oxygen therapy is often required.


Bottom Line

Scuba diving and flying are both exhilarating, but your body needs time to adjust between them. Following FAA and medical guidance is the simplest way to avoid potentially life-threatening decompression sickness.


Rule of Thumb:

Wait 12 hours after a single no-decompression dive. Wait 24 hours after multiple or decompression dives —And if you’re unsure, wait longer.


That extra time on the ground might just save your life — and your ability to keep flying.



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