AA's contract isn't simple, but the very basics are:
Depart Time: 0600-1800 = 12.5hrs Scheduled, 13hrs Rescheduled & 14hrs Maximum on duty.
Depart Time: 1800-2100 = 11hrs, 12hrs, & 13hrs respectively.
Depart Time: 2100-0600 = 10hrs, 11hrs, & 12 hrs respectively.
That's the real simple version, but you have to account for the FAA's newest interpretation as well.... no pilot can actually takeoff (go airborne) unless he can "reasonably expect" to arrive at destination at a time when, at that point in time, he can "look-back" over the previous 24 hours and identify 8 hours of uninterrupted off-duty time. Sometimes you gotta love government lawyers for finding the most complex ways of doing things.
FWIW, AA's "no-fault" fatigue policy prohibits company actions toward a pilot who is too fatigued to fly a trip. Claim fatigue a lot and you might be sent to a company doctor, but there is no coercion to fly when tired.