B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Fatigue; Physiological - Other
Flight Deck / Cabin / Aircraft Event Other / Unknown
General None Reported / Taken
Company Policy; Human Factors
The company continues to build pairings that work completely counter to the circadian rhythms of normal day to day living. They build all night flying on the beginning of trips where pilots are coming from days off; and from a day schedule into an all nighter. This is not natural. Further; after such a first flight; they schedule a 12 hour layover where pilots are getting little over six hours sleep; if that. This is something pilots do not talk about. A minimum of 24hrs (30hrs if west to east all nighter flown) should be mandated by FAA after an all night flight. This would ensure a rest period to catch up and balance a pilots circadian rhythm. A natural pairing would be to start a trip on a natural day schedule maybe flying late afternoon landing at midnight or slightly after midnight. This would create a gradual progression into night flying. My flight sequence in question started this way. The first flight was an all-night flight was scheduled to ZZZ. This pairing was originally scheduled as a XA52 departure; with an arrival at XG54.Our contract defines All Night Flying as a flight segment; any portion of which; scheduled to operate from 02:30-03:29.We ended up late with a return to gate for a SPEED BRAKE DO NOT ARM light causing a departure of XA10. This resulted in an arrival of XH12; over 1 hour and 18 minutes late. Our layover was scheduled for XC11. I got to room at XJ00 and laid my head down at XJ15 I woke up at XO30 receiving 5:15 hours of sleep.  Was not able to get back to sleep.I was rested enough to sign in 'fit for duty' as I felt good enough to fly. This is where the company places the next problematic area; through scheduling; to circadian rhythm and flying. Instead of scheduling--on last day of a pairing - AFTER AN ALL NIGHT FLIGHT-ONE LEG home...they schedule two legs. These are not short legs either. Consider this pairing; a first flight of 2:18 minutes; with a 1:05 sit; to then pick up the next leg; a 3:47 minute flight to our home base.  By the way; on paper this seems reasonable; [although] some past pairings I have flown this scenario with a sit greater than three hours. That is absolutely atrocious how bad you feel after that trip. While airborne on our first leg both myself and First Officer discussed how tired we were and made a joint decision it was not in the best interest of flight safety to continue. Mind you this was a last leg to get home; but we still felt it prudent to call fatigued. Here are some suggestions to the FAA on fatigue concerns; which I continue to write in about regardless of whether I call in fatigued or not; concerns based on pairings our company continues to build.1. Minimum 24hrs off after any all-night flight. (30hrs if from west coast to east coast all nighter)2. All night flights should be avoided on the first flight of a pairing. (It is unnatural to go from a daytime schedule to an all night flying environment without a gradual transition)3. If an all night flight is flown in the middle of a pairing; a minimum of 24hrs off from duty is mandated. (Established from where a pilot started. West to east 30hrs. East to west 24hrs.)4. If the FAA is going to allow airlines to schedule all night flying; without a requirement to have 24hrs off from duty after the all night flight; then no more than one leg may be flown to ensure that pilots are not being pushed to an unsafe level of performance simply because the corporation is willing to allow an 'acceptable risk' formula for operating commercial aircraft.
A B737 Captain discussed; with pertinent details; his concerns with respect to the fatigue inducing manner in which flight crew pairing sequences including all night flying are scheduled by his air carrier. He follows up the discussion of those issues with suggested solutions.