What was found
BURNING SMELL COMING FROM OUTSIDE THE LT AFT FUSELAGE. (NEAR TAILCONE AND NR 1 ENGINE). ACRID AND OILY CONSISTENCY. RAN APU & BOTH ENGINES FOR A PERIOD OF 30 MINS. INSPECTED LEFT AFT FUSELAGE, NR 1 AND 2 ENGINES FOR ANY LEAKS AND NONE WERE NOTED. OPENED TAIL CONE DOOR, INSPECTED APU & ECU FOR LEAKS AND ALSO NO DEFECTS WERE NOTED. COULD NOT DUPLICATE DISCREPANCY. WORK ACCOMPLISHED IAW CESSNA CE750 MM CH 21-51-00, 71-00-04 AND 49-10-00