Citation Excel (C560XL)
Flight Crew Air Transport Pilot (ATP)
Fatigue; Distraction
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft; Human Factors
The aircraft that I was in command of had a MEL for the cabin door light which had been written up by me. I read the operational procedures of the MEL at the time it was written up (approximately 1.5 hrs before takeoff.) We took off as scheduled and flew initially an assigned heading of 090 degrees. We were given various step climbs and were eventually cleared to 16;000 FT. As we passed through approximately 15;000 FT the CAB ALT annunciator came on with the Master Warning. Required memory items were completed and passenger was informed to keep their seat belts on and that we had to return to [the departure airport] due to pressurization problem. We asked ATC for a lower altitude and a heading and started our descent and turn. The flight went uneventful back to [the departure airport.] I was distracted and might have missed item number 2 on the operational procedures which could be the reason for the CAB ALT annunciator. Obviously I should have been more focused on the operational procedures. Distraction and a possibility of fatigue that I didn't recognize could have played a factor as well.
We were at 15;500 FT we got a CAB ALT and master warning. We performed memory items and asked for a turn and a descent. We ran the checklist and continued back to [the departure airport.] They gave us direct to [the departure airport] and we landed with no problems. MEL'd the ACM after landing.
CE-560XL flight crew experienced a Cabin Altitude warning during climb at 15;000 FT. They declared an emergency and returned to their departure airport.