From the FOM:

2.5 Fatigue

It is the crewmember’s responsibility to be properly rested for each phase of the trip. However, if circumstances prevent this, no FedEx crewmember should feel pressured to fly when not properly rested. A crewmember who is fatigued should immediately notify Crew Scheduling if unable to complete a trip.



Should an accident, incident, or flight violation occur, fatigue should not be a contributing factor since the FOM clearly states that a pilot should not fly fatigued.