Narrative:

I was climbing with the autopilot; instructed to climb to 10;000 ft when the approach controller started nearly yelling at me to descend instantly. When I looked at my altimeter it read 10;200 ft and so I quickly descended to 10;000 ft . He continued to yell; repeatedly telling me to descend to 10;000 ft; even though I informed him multiple times that that's exactly where I was; and he then told me there was traffic descending above me. He accused me of being at 10;500 ft and climbing when I seemed confused as to his demeanor. I'm not sure if he was exaggerating or if the transponder in the airplane was sending faulty information; but I am very sure I was nowhere near 10;500 ft. I was likely still in a slow climb; but with a fully loaded C208B (caravan) I doubt my climb rate could have been very much. Again; I'm not sure what he saw on his screen; but I know I was only 200 ft high; not 500. A definite factor here is fatigue. I was fatigued to the point of losing situational awareness and not knowing whether I had reached 10;000 ft because of the schedule I fly 6 days a week; 14 hour days; and flights every morning at 6:30 am local time. I realize the FAA allows 9 hours rest for scheduled part 135 operations; but I would strongly consider raising that limit. It may be safe for some pilots; but every person has different needs; and instances like this make me realize how dangerous extended schedules that don't allow for much actual sleep can be.

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Original NASA ASRS Text

Title: A C208B pilot reported fatigue from long duty days; six days a week and momentarily climbing 200 FT about the 10;000 FT altitude assigned before an Approach Controller urgently demanded a descent.

Narrative: I was climbing with the autopilot; instructed to climb to 10;000 FT when the Approach Controller started nearly yelling at me to descend instantly. When I looked at my altimeter it read 10;200 FT and so I quickly descended to 10;000 FT . He continued to yell; repeatedly telling me to descend to 10;000 FT; even though I informed him multiple times that that's exactly where I was; and he then told me there was traffic descending above me. He accused me of being at 10;500 FT and climbing when I seemed confused as to his demeanor. I'm not sure if he was exaggerating or if the transponder in the airplane was sending faulty information; but I am very sure I was nowhere near 10;500 FT. I was likely still in a slow climb; but with a fully loaded C208B (Caravan) I doubt my climb rate could have been very much. Again; I'm not sure what he saw on his screen; but I know I was only 200 FT high; not 500. A definite factor here is fatigue. I was fatigued to the point of losing situational awareness and not knowing whether I had reached 10;000 FT because of the schedule I fly 6 days a week; 14 hour days; and flights every morning at 6:30 am local time. I realize the FAA allows 9 hours rest for scheduled Part 135 operations; but I would STRONGLY consider raising that limit. It may be safe for some pilots; but every person has different needs; and instances like this make me realize how dangerous extended schedules that don't allow for much actual sleep can be.

Data retrieved from NASA's ASRS site as of July 2013 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.