As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI, CABIN BEGAN TO FILL WITH SMOKE. PLACED RT PACK ON MEL. RT PACK MAKING LOUD GRINDING NOISE AND EXCESSIVE VIBRATION. RAN RIGHT ENGINE, CHECKED NR 2 BLEED AND APU BLEED ON NR 1 PACK. NO SMOKE NOTED. REMOVED AND REPLACED AIR CYCLE MACHINE IAW AMM. OPS CHECK GOOD. (M)