The company pilot's poor judgment before and during the flight, including turning the oxygen system ready switch to the OFF position after he conducted the preflight inspection and using an unapproved checklist, which did not provide guidance for a fractured windshield and resulted in his depressurizing the airplane. Members Hersman and Sumwalt did not approve this probable cause. Member Hersman filed a dissenting statement, with which Member Sumwalt concurred. The statement can be found in the public docket for this accident.