CAAP Commercial Pilot License (CPL) Air Law Practice Exam

The correct altitude at which all flight crew members should continuously use breathing oxygen is 14,000 feet. This requirement is part of regulations set forth primarily to ensure the safety and health of crew members in environments where the atmospheric pressure and oxygen levels can significantly decrease. At or above this altitude, the partial pressure of oxygen is no longer sufficient to prevent hypoxia, which is a condition resulting from the body’s inadequate supply of oxygen.

By mandating the use of supplemental oxygen at this altitude, regulations help mitigate the risks associated with flying at higher elevations where the deterioration of cognitive and physical performance can occur more rapidly without adequate oxygen. This ensures that flight crew members remain fully alert and capable of performing their duties effectively, which is vital for the safety of the aircraft and all onboard.

In aviation regulations, these prescribed altitudes are carefully determined based on physiological studies and understanding of human responses to reduced oxygen environments. Therefore, the stipulation for continuous use at 14,000 feet reflects a consensus on maintaining a safe operational environment for crew welfare.