What was found
FLIGHT CREW REPORTED A STRONG BURNING ODOR IN COCKPIT, FIRST CLASS CABIN AND REAR OF AIRCRAFT. MAINTENANCE CHECKED APU INLET, NO OBSTUCTIONS. FOUND NO LEAKS IN APU COMPARTMENT. PERFORMED OPERATIONAL CHECK OF APU. RAN APU WITH BLEED ON/OFF, APU GENERATOR ON/OFF, SINGLE AND DUAL PACK OPERATION. COULD NOT DUPLICATE ODOR. PERFORMED APU INSPECTION - REFERENCE J/C 26L00021002. NO DEFECTS NOTED. SERVICED APU WITH ONE QUART OF OIL. APU OK FOR SERVICE.