As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PUNGENT ODOR/SMOKE IN AIRCRAFT ON ENGINE PNEUMATICS AT HIGH ENGINE POWER. FOUND APU GEARBOX CRACKED AT STARTER PAD STUDS AT ONE AND THREE O'CLOCK POSITIONS (LOOKING AFT). SMOKE ATTRIBUTED TO OIL BEING INTRODUCED INTO PNEUMATIC DUCTING. REMOVED AND REPLACED GEARBOX.