The FAA has strict regulations on the number of consecutive hours a charter pilot can be on duty.

The standard duty day for a crew is 14hrs total, which includes the time required to do pre and post-flight routines. The general rule of thumb for a standard duty is that the charterer can have the aircraft under their control for a maximum of 12hrs, which allows for crew to perform pre and post-flight checks.

There are complexities involved in the FAA crew duty day and details will vary by trip and aircraft.