Complex sentence: She found a small Siebel Fh 104 plane that did not have a pilot, and while it was being fueled she studied the plane's manual, as she had never before flown this model.
Split into simpler sentences: She found a small Siebel Fh 104 plane that did not have a pilot. While it was being fueled she studied the plane's manual, as she had never before flown this model.