During a flight above 14,000 feet, what is the recommended oxygen requirement for the crew?

The correct answer is that 100% of the crew must have access to supplemental oxygen when flying above 14,000 feet. This requirement is based on aviation safety regulations that mandate the necessity of oxygen to ensure crew members can maintain performance and cognitive function at higher altitudes, where the atmospheric pressure decreases, and the availability of oxygen diminishes.

At altitudes above 14,000 feet, the risk of hypoxia increases significantly, which can impair judgment, coordination, and the ability to perform critical tasks. Therefore, it is essential that every crew member has access to oxygen equipment to safeguard against these risks, irrespective of their specific duties during flight.

Other options suggest varying levels of access or necessity that do not align with industry standards for safety. The specifications set forth are designed to ensure a safe working environment for all crew members when operating at high altitudes.