As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 3340 - DCA-HPN - DURING DESCENT INTO HPN WITH LOW POWER SETTING, THE CABIN BEGAN TO FILL WITH SMOKE. CYCLED EACH BLEED OFF AND RAISED CABIN ALTITUDE TO REMOVE SMOKE. THE AIRCRAFT LANDED IN HPN WITHOUT INCIDENT. REMOVED AND REPLACED THE P2.5 AIR SWITCHING VALVE, NO FIX. REMOVED AND REPLACED THE NR 1 ENGINE. (M)