As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING APPROACH THE FLIGHT ATTENDANT REPORTS MUSTY BURNING SMELL AT SEAT ROW 5 AT 2500 FT WHEN GEAR EXTENDED. MAINTENANCE REPLACED THE APU PER TASK 26L31049003. A SATISFACTORY LEAK/ OPERAIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS NOTED.