Narrative:

During preflight I had two maintenance issues that required phone calls to control. When I started the APU; I must have forgotten to turn on the APU generator; so the plane was operating on the ship's battery for at least 45 minutes. When I got to the cockpit I noticed the screens were blank and an alert sounded over the speakers. I noticed that the APU gen was off line. In a reflex reaction; I closed the generator breaker. As a result the battery temperature jumped to 158 degrees. The APU gen would not come back on line. We shut down the airplane; and called the chief pilot to tell him what was going on. He agreed the plane needed to be written up. I suggest we leave the APU gen switch in the 'on' position at all times. Even during shutdown.

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Original NASA ASRS Text

Title: A Citation 560XL Captain failed to insure the APU Generator was selected on when he started the APU 45 minutes prior to completion of his preflight duties. Upon returning to the cockpit he discovered the cockpit dark and the battery depleted and overheated.

Narrative: During preflight I had two maintenance issues that required phone calls to control. When I started the APU; I must have forgotten to turn on the APU generator; so the plane was operating on the ship's battery for at least 45 minutes. When I got to the cockpit I noticed the screens were blank and an alert sounded over the speakers. I noticed that the APU GEN was off line. In a reflex reaction; I closed the Generator Breaker. As a result the Battery temperature jumped to 158 degrees. The APU GEN would not come back on line. We shut down the airplane; and called the Chief Pilot to tell him what was going on. He agreed the plane needed to be written up. I suggest we leave the APU GEN switch in the 'ON' position at all times. Even during shutdown.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.