As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:N/A CREW NOTICED ELECTRICAL SMOKE ODOR DURING TAXI. DID BLOCK TURNBACK FOR FURTHER INSPECTION. CREW COULD NOT DETERMINE SOURCE. FOUND AIR DISTRIBUTION DUCT INSULATION DETERIOATED AND HAD FALLEN DOWN ACROSS WIRING AND C/BS IN THE UPPER PORTION OF HTE OVERHEAD P-11 PANEL. REMOVED DETEROIATED INSULATION AND CLEANED P-11 PANEL. NO OTHER FAULTS FOUND. EO 757-5310-20596-A ISSUED FOR REMOVAL OF INSULATION.