What altitude must be maintained for supplemental oxygen use for more than 30 minutes?

The correct altitude for the use of supplemental oxygen for more than 30 minutes is 12,500 feet. At this elevation, the partial pressure of oxygen in the atmosphere decreases, which can lead to hypoxia, a condition caused by inadequate oxygen supply to the body. The regulations stipulate that pilots must use supplemental oxygen above this altitude to mitigate the risk of impaired cognitive function and other health issues related to lower oxygen levels.

In general, the necessity for supplemental oxygen increases with altitude. While there are various altitudes where oxygen becomes more critical for flight safety, maintaining oxygen use at 12,500 feet ensures that pilots and passengers can function safely during prolonged exposure to lower atmospheric pressures. Understanding the physiology of hypoxia and the regulations surrounding supplemental oxygen is crucial for safe helicopter operation.