Complex sentence: Unfortunately most sustained "g"-forces incurred by pilots is applied longitudinally, this has led to experimentation with prone pilot aircraft designs which lies the pilot face down or (more successfully) reclined positions for astronauts.
Split into simpler sentences: Unfortunately most sustained "g"-forces incurred by pilots is applied longitudinally. This has led to experimentation with prone pilot aircraft designs which lies the pilot face down or (more successfully) reclined positions for astronauts.