Complex sentence: Stalling an aircraft (increasing the angle of attack to a point at which the wings fail to produce enough lift), is dangerous and can result in a crash if the pilot fails to quickly react in the proper manner.
Split into simpler sentences: Stalling an aircraft (increasing the angle of attack to a point at which the wings fail to produce enough lift). Stalls are dangerous and can result in a crash if the pilot fails to quickly react in the proper manner.