As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CROSS BLEED START OF RIGHT ENGINE, CABIN AND COCKPIT FILLED WITH SMOKE. SMOKE CLEARED AFTER ENGINE ABORT AND SHUT OF LEFT PACK. ISSUED MEL 21-12 LT PACK. REMOVED AND REPLACED LEFT AIR CYCLE MACHINE IAW CRJ700/900 AMM 21-51-08. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.