There are a minimum number of hours specified by Federal Aviation Regulations (FARs) Part 61. I don't know the average now, but the national average used to be about 20 hours over the minimum. Those students who took less than the national average were those who took 3 to 5 lessons a week (some went 7 days).
A rare but very serious risk associated with blood transfusions is transfusion-related acute lung injury (TRALI). It occurs more often with platelets and plasma than with red cells. TRALI is a poorly understood condition, in which a personâs lungs suddenly become very inflamed within six hours of the transfusion.
Blood types are very important when a blood transfusion is necessary. In a blood transfusion, a patient must receive a blood type compatible with his or her own blood type. If the blood types are not compatible, red blood cells will clump together, making clots that can block blood vessels and cause death.