As the lift or thrust increases and the flight path changes, something happens to the pilot and crew. They feel as if a weight is pressing on them; they feel heavier! This is called a load or g factor. If the aircraft is traveling normally, the load or g factor is 1 (normal weight). If the airplane is in a turn or accelerating the load or g factor can increase. If the load factor is 2 then the pilot and crew would feel 2 g's.

Military aircraft can experience very high g's during turns or acceleration. The problem is that people cannot take very high g's and stay conscious (awake)! Fighter pilots learn how to withstand g forces and airplane computers make sure the plane will not create higher g's than the pilot can stand.

Small and commercial aircraft usually do not go above 1.5 g's during turns or acceleration.

When an airplane banks (turns) it will lose lift and altitude. The pilot may avoid this by increasing thrust or slightly lifting the nose of the aircraft. This increases lift enough to keep the airplane level during the turn.