What was found
(AIRCRAFT NOT GROUNDED) BOTH AFT FA'S AND ONE PAX REPORTED MUSTY ODOR. CONFIG: APU OFF, ENG 1 & 2 BLEEDS ON, BOTH PACKS ON, ISOLATION VALVE CLOSED. EVENT BEGAN ON DECENT AT APPROX 800 FT. DURATION EST. 10 MIN. DISSIPATED ON LANDING. NO CLOUDS OR HUMIDITY. NO PREVIOUS RESENT DEICE. NO ILLNESS REPORTED. /C/W OIL TYPE SMELL - PHASE 2 WORK CARD NO. 21-000-002ITEM: 1C/W OIL TYPE SMELL - PHASE 2 WORK CARD NO. 21-000-002. INSTALLED COMPRESOR BORESCOPE PLUG IAW AMM 49-20--00-200-003-AITEM: 1INSTALLED COMPRESOR BORESCOPE PLUG IAW AMM 49-20--00-200-003-A.