What was found
FLT 4469 - DURING APPROACH INTO ATL FROM ROA, THE CREW NOTICED AN ODD ODOR WHEN THE PACKS WERE ON THE ENGINE BLEED AIR AT HIGHER POWER SETTINGS ONLY. IT APPEARED TO BE A FAINT OIL OR HOT PLASTIC ODOR WHICH OCCURRED INTERMITTENTLY DURING APPROACH. THE AIRCRAFT LANDED SAFELY IN ATL. THE SMELL WAS NOT NOTICED AFTER LANDING UPON SWITCHING TO THE AUXILIARY POWER UNIT BLEED AIR. MAINTENANCE COULD NOT DUPLICATE THE ODD SMELL ON THE GROUND USING THE AUXILIARY POWER UNIT BLEED AIR. ALL EICAS ENVIRONMENTAL CONTROL SYSTEM INDICATIONS WERE NORMAL. (M)