As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURNING SMELL IN AFT CABIN ON TAKEOFF AND LANDING. LAST 2 LEGS REPEAT WRITEUP. ACP HIGH POWER RUNS ISOLATING PACKS AND ENGINE BLEED SOURCES. TESTED LIGHTS AT ALL SETTINGS TESTED COFFEMAKERS, NO ABNORMAL SMELLS. FOUND OIL IN APU COMPARTMENT AND COMPRESSOR INLET. CREATED WRITE UP TO REPLACE APU. EVIDENCE OF OIL LEAK IN APU COMPARTMENT, APPEARS TO HAVE OIL IN INLET OF COMPRESSOR. REPLACED APU.