Which scenario requires at least a 12-hour delay before flying to a cabin altitude of 8000 feet or less?

Which scenario requires at least a 12-hour delay before flying to a cabin altitude of 8000 feet or less?

• A. Diving with a controlled ascent
• B. Diving without controlled ascent
• C. No diving before flight
• D. Diving deeper than 60 feet

Answer: (B)

When you dive, your body absorbs nitrogen from the breathing mix under pressure. Flying later exposes you to lower cabin pressure, which can cause dissolved nitrogen to come out of solution and form bubbles in tissues—decompression sickness. A controlled ascent during the dive helps off‑gas nitrogen more gradually, reducing the amount that remains dissolved. If you dive without a controlled ascent, more nitrogen stays in solution and the risk of bubbles forming is higher when you later fly, so a delay of at least 12 hours before flying to a cabin altitude of 8000 feet or less is recommended. If you didn’t dive at all, or if you completed a controlled ascent, the need for such a delay isn’t the same. Deeper dives generally carry greater risk, but the specific scenario that requires the 12-hour wait in this context is diving without a controlled ascent.

When you dive, your body absorbs nitrogen from the breathing mix under pressure. Flying later exposes you to lower cabin pressure, which can cause dissolved nitrogen to come out of solution and form bubbles in tissues—decompression sickness. A controlled ascent during the dive helps off‑gas nitrogen more gradually, reducing the amount that remains dissolved. If you dive without a controlled ascent, more nitrogen stays in solution and the risk of bubbles forming is higher when you later fly, so a delay of at least 12 hours before flying to a cabin altitude of 8000 feet or less is recommended. If you didn’t dive at all, or if you completed a controlled ascent, the need for such a delay isn’t the same. Deeper dives generally carry greater risk, but the specific scenario that requires the 12-hour wait in this context is diving without a controlled ascent.