Narrative:

Flight attendant came up to cockpit, said passenger smelled smoke. First thought smell came from galley crews. Smell grew stronger, even with galley power turned off. First officer went back to cabin to try to verify origin of smoke. Came back to cockpit and told me the cabin was completely filled with smoke. Declared an emergency. Talked with passenger to inform them of our intentions and advised the flight attendants. Made emergency descent to 4000 ft while following the QRH for smoke removal and depressurizing aircraft. Made a normal landing in richmond, va, with emergency equipment standing by. After landing, taxi to gate, deplaned the passenger. Upon inspection by mechanics, gasper fan was found to have shorted out. Removed fan to confirm that was the problem. Aircraft was released on MEL of the gasper fan for flight then proceeded to dca without further incident.

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Original NASA ASRS Text

Title: A B737-200 PERFORMS AN EMER DSCNT AND DIVERTS TO RIC, VA, WHEN SMOKE FILLS THE PAX CABIN.

Narrative: FLT ATTENDANT CAME UP TO COCKPIT, SAID PAX SMELLED SMOKE. FIRST THOUGHT SMELL CAME FROM GALLEY CREWS. SMELL GREW STRONGER, EVEN WITH GALLEY PWR TURNED OFF. FO WENT BACK TO CABIN TO TRY TO VERIFY ORIGIN OF SMOKE. CAME BACK TO COCKPIT AND TOLD ME THE CABIN WAS COMPLETELY FILLED WITH SMOKE. DECLARED AN EMER. TALKED WITH PAX TO INFORM THEM OF OUR INTENTIONS AND ADVISED THE FLT ATTENDANTS. MADE EMER DSCNT TO 4000 FT WHILE FOLLOWING THE QRH FOR SMOKE REMOVAL AND DEPRESSURIZING ACFT. MADE A NORMAL LNDG IN RICHMOND, VA, WITH EMER EQUIP STANDING BY. AFTER LNDG, TAXI TO GATE, DEPLANED THE PAX. UPON INSPECTION BY MECHS, GASPER FAN WAS FOUND TO HAVE SHORTED OUT. REMOVED FAN TO CONFIRM THAT WAS THE PROB. ACFT WAS RELEASED ON MEL OF THE GASPER FAN FOR FLT THEN PROCEEDED TO DCA WITHOUT FURTHER INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.