For decompression greater than 4 hours, how long before flying is required?

When considering the appropriate waiting period before flying following a prolonged decompression experience of greater than 4 hours, the recommended guideline is indeed 48 hours. This recommendation is rooted in physiological understanding of how the body eliminates nitrogen after a significant exposure to reduced atmospheric pressure, which can lead to nitrogen bubbles forming in tissues and blood—a condition known as decompression sickness.

After experiencing decompression, the body needs sufficient time to off-gas or eliminate these nitrogen bubbles safely. A 48-hour waiting period allows for this process to occur, minimizing the risk of complications such as decompression sickness when the individual resumes flying. It is essential for pilots and crew to adhere to this guideline to ensure their safety and that of others on board an aircraft.