What was found
STRONG BURNED SCENT FROM APU BLEED UPON APU STARTUP. (NO SMOKE/ NO FUMES). T/S PER WC 0550-2001 NO ODOR WHEN ARRIVED AT AIRPLANE. NO ODOR NOTICED ON ENG BLEED OR APU. COMPLETED WC 0550-2003 FOR LEFT PACK, RT PACK STILL NEEDS TO BE COMPLETED FOR WC 0550-2003. BOTH RECIRC FILTERS NEED REPLACED. (DE 335038) COMPLETED WORK-CARD 0550-2003 FOR RH PACK & REPLACED RECIRC FILTERS NO ODORS NOTICED. (LP# 4059534, 0180464,0180457 )