How long should an aircrew member wait to fly after donating blood?

An aircrew member should wait 72 hours after donating blood before flying. This recommendation is in place due to the potential effects of blood donation on the body, including a temporary decrease in hemoglobin levels and a reduced ability to transport oxygen efficiently. After donating blood, individuals may experience fatigue, dizziness, or a lowered physical performance, which could adversely affect their ability to operate an aircraft safely.

Waiting for 72 hours allows the body to recover from the donation, ensuring that the aircrew member has regained sufficient blood volume and hemoglobin levels to perform their duties effectively. This precaution is crucial for maintaining safety in aviation operations, as any impairment, even slight, can pose significant risks during flight.