A320 First Officer describes a demanding trip and home life that results in a fatigue call to crew scheduling.

Narrative

While on the final day of a 3-day trip; I took myself off the trip due to fatigue. This was a demanding 3-day trip with 20 hours of flight time; multiple legs and 2 late-night layovers. While flying the first leg of day 3; both the Captain and I remarked several times that we were very tired. Following our arrival; we were scheduled for a turn to finish the trip. While briefing in Operations; Dispatch informed us that we would be changing planes for the return flight and departing late (approximately 45 minutes). While walking to the gate; Dispatch called the Captain with an updated plan which would put us back in base after midnight; nearly 3 hours late. When the Captain informed me of this; I became extremely angry. We discussed our fatigue and the possibility of taking ourselves off of the turn. The Captain decided to continue and told me he supported whatever decision I made regarding the trip. He departed for the plane and told me to do what I needed to do. I pulled out my cell phone and began to make a call to scheduling; but instead of completing the call; I hurled my phone against the wall. Since there was no activity at the gate; I don't think anyone witnessed my anger; but as I was picking up the pieces of my shattered phone; I realized I was in no condition to fly. I returned to Operations; called scheduling to inform them that I was fatigued and would not be flying the turn. This incident was not the result of a one-time late-night flight; but the cumulative effects of several months of fatigue; stress and frustration. I realize that most every pilot is dealing with these problems. The past 6 months for me have been particularly difficult due to a series of never-ending colds; EXTREME CHRONIC FATIGUE; and a rash of late-night arrivals; deferred maintenance; trip changes; musical Captains; merger rumors and other stress at work. When [I am] at home; I must assume parental duties first thing in the morning to accommodate my wife's work schedule. (You can't support a family in this area on A320 First Officer pay.) Because of this; I am often unable to recover from one trip before beginning another. This situation has been exacerbated recently because I have flown several trips which have arrived back at home base 3 or 4 hours later than scheduled. I am in a state of EXTREME FATIGUE all the time; and as a result; I have become unreasonably irritable. I have reacted to minor problems and inconveniences with anger in some cases and apathy in others.