As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN APU FIRST STARTS STRONG DIRTY SOCKS FEET SMELL IN CABIN/ COCKPIT. UPON STARTING APU AFTER LANDING BURNT TOAST SMELL IN CABIN/COCKPIT. AS PER NO GO ODI PERFORMED A/C 0550-2002. BEGAN W/C 0550-2001 UP TO STEP 4 (DP 230877) C/W REMAINING STEPS ON A220 AMDS WORKCARD 0550-2001 AND 0550-2003. R/R STARTER MOTOR PACKING IAW A220 AMP 49-41. OPS CHECK GOOD. NO LEAKS.(LP# 5367210, 5367208)