As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE BASE VISIT INSPECTION FOUND AUXILIARY POWER UNIT COWL HAD CHAFED SKIN AND ELONGATED HOLES AT AFT MOST DRAIN PUMP TUBING SUPPORT BRACKET ATTACH POINT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REPAIRED APU COWL IN ACCORDANCE WITH ENGINEERING ORDER EM-53MR-1755. THE AIRCRAFT WAS RETURNED TO SERVICE.