No Fly/No Fly Time

Introduction

No Fly Time, also known as No Fly Zone or No Fly Period, is the recommended time interval that divers should wait between their last dive and boarding an airplane. This critical precautionary measure aims to prevent Decompression Sickness (DCS) and other altitude-related issues that may arise when flying too soon after scuba diving.

Background

Scuba diving and flying are two activities that involve significant pressure changes. While diving, the body is exposed to increased pressure as the diver descends, causing the inert gases (primarily nitrogen) to dissolve in the tissues. Upon ascent, the pressure decreases, allowing these dissolved gases to gradually exit the body. However, if the ascent is too rapid or if the diver flies soon after diving, the dissolved gases may form bubbles in the tissues, leading to Decompression Sickness (DCS).

Decompression Sickness (DCS)

DCS, also known as the bends, caisson disease, or divers’ disease, is a potentially serious condition that results from the formation of gas bubbles in the body due to rapid changes in pressure. DCS can manifest in various ways, from mild symptoms like joint pain, skin rash, and fatigue to severe complications, including paralysis, pulmonary embolism, and even death. The risk of DCS increases with factors such as the depth and duration of the dive, rapid ascents, and flying too soon after diving.

Role of No Fly Time in DCS Prevention

To minimize the risk of DCS, guidelines have been established to recommend the appropriate time interval between diving and flying. This No Fly Time allows the body sufficient time to off-gas the dissolved nitrogen, reducing the risk of bubble formation and DCS.

No Fly Time Guidelines

The guidelines for No Fly Time vary depending on the source, but the most widely accepted recommendations come from the Divers Alert Network (DAN) and professional diving organizations such as PADI and NAUI. According to DAN, the following No Fly Times are recommended:

1. For single no-decompression dives, a minimum pre-flight surface interval of 12 hours is suggested.
2. For multiple no-decompression dives per day or multiple days of diving, a minimum pre-flight surface interval of 18 hours is recommended.
3. For decompression dives (dives requiring staged decompression stops), a pre-flight surface interval of more than 18 hours is advised, with some experts recommending 24 to 48 hours.

It is essential to note that these recommendations are general guidelines and may not apply to every individual. Factors such as age, health, fitness level, and dive profile can influence a person’s susceptibility to DCS. Divers should consult their dive tables, dive computers, or instructors to determine their optimal No Fly Time.

Altitude Considerations

In addition to commercial air travel, divers should also be aware of altitude changes when traveling by car or hiking to higher elevations after diving. Altitude exposures of 300 meters (1,000 feet) or more above sea level within 12 to 24 hours after diving may also increase the risk of DCS. To avoid complications, divers should follow the same No Fly Time guidelines when considering altitude changes post-dive.

Safety Precautions and Responsible Diving

Understanding and adhering to the No Fly Time guidelines is crucial for reducing the risk of DCS and ensuring a safe and enjoyable diving experience. Other essential safety precautions include:

1. Proper dive planning: Utilize dive tables or computers to plan dives within established no-decompression limits and ascent rates.
2. Controlled ascent: Maintain a slow and steady ascent rate, with safety stops as needed, especially when diving deep or for extended periods.
3. Hydration: Stay well-hydrated before and after dives to facilitate efficient off-gassing of nitrogen and reduce the risk of DCS. 4. Avoidance of alcohol and drugs: Refrain from consuming alcohol or drugs before diving, as these substances can impair judgment, increase dehydration, and hinder off-gassing.
4. Dive within personal limits: Know your skill level and physical limitations, and avoid diving in conditions or environments that exceed your experience and training.
5. Buddy system: Dive with a buddy or a group, ensuring that everyone is aware of the dive plan and can monitor each other’s well-being.
6. Regular health check-ups: Undergo periodic medical evaluations, particularly if you have pre-existing conditions or risk factors that may increase your susceptibility to DCS.

Conclusion

No Fly Time is a crucial safety guideline that divers must observe to minimize the risk of Decompression Sickness and other altitude-related complications. By adhering to established No Fly Time recommendations, divers can enjoy the underwater world while ensuring their safety and well-being. Remember that responsible diving practices, such as proper dive planning, controlled ascents, hydration, and diving within personal limits, are also essential for a safe and enjoyable experience. Always consult your dive tables, dive computers, or instructors to determine your optimal No Fly Time and follow best practices to ensure a lifetime of thrilling underwater adventures.