Smoke in cockpit in C650 creates need for emergency descent, diversion to alternate.

Attributes
ACN	358845
Time
Date	199701
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bna
State Reference	TN
Altitude	msl bound lower : 12000 msl bound upper : 39000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	general aviation : corporate
Make Model Name	Citation III, VI, VII
Operating Under FAR Part	Part 91
Navigation In Use	Other Other
Flight Phase	cruise other other other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 115 flight time total : 9300 flight time type : 1500
ASRS Report	358845
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 7200 flight time type : 1500
ASRS Report	358847
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : exited adverse environment other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

We were in cruise flight at FL390 from stuart, fl, to mli. Approximately 85 mi ese of bna both myself and the first officer smelled smoke. We checked all circuit breakers and system. All appeared normal. No system anomalies were observed. Within a min or two, smoke was observed coming from under captain's instrument panel. We immediately notified ZTL and requested a lower altitude. They issued us lower immediately. As we started down, the cockpit and cabin filled with smoke. We had donned our masks/goggles and initiated emergency descent procedures. ARTCC gave us an uninterrupted descent to 12000 ft and allowed us to divert to our requested airport of bna. Note: during descent, all smoke cleared from the cockpit and cabin. The smoke never returned once cleared. We landed at bna without any further problem. The aircraft remained in bna overnight to allow our company maintenance technicians to come to bna. The aircraft was fully inspected. The problem was discovered to be the wemac boost fan which had burned itself out, causing the smoke. All other system were checked and found normal. The wemac boost fan was then secured and the aircraft was released to return to mli. We had no further problems. Note: this flight was an empty (no passenger) flight at time of occurrence.

Original NASA ASRS Text

Title: SMOKE IN COCKPIT IN C650 CREATES NEED FOR EMER DSCNT, DIVERSION TO ALTERNATE.

Narrative: WE WERE IN CRUISE FLT AT FL390 FROM STUART, FL, TO MLI. APPROX 85 MI ESE OF BNA BOTH MYSELF AND THE FO SMELLED SMOKE. WE CHKED ALL CIRCUIT BREAKERS AND SYS. ALL APPEARED NORMAL. NO SYS ANOMALIES WERE OBSERVED. WITHIN A MIN OR TWO, SMOKE WAS OBSERVED COMING FROM UNDER CAPT'S INST PANEL. WE IMMEDIATELY NOTIFIED ZTL AND REQUESTED A LOWER ALT. THEY ISSUED US LOWER IMMEDIATELY. AS WE STARTED DOWN, THE COCKPIT AND CABIN FILLED WITH SMOKE. WE HAD DONNED OUR MASKS/GOGGLES AND INITIATED EMER DSCNT PROCS. ARTCC GAVE US AN UNINTERRUPTED DSCNT TO 12000 FT AND ALLOWED US TO DIVERT TO OUR REQUESTED ARPT OF BNA. NOTE: DURING DSCNT, ALL SMOKE CLRED FROM THE COCKPIT AND CABIN. THE SMOKE NEVER RETURNED ONCE CLRED. WE LANDED AT BNA WITHOUT ANY FURTHER PROB. THE ACFT REMAINED IN BNA OVERNIGHT TO ALLOW OUR COMPANY MAINT TECHNICIANS TO COME TO BNA. THE ACFT WAS FULLY INSPECTED. THE PROB WAS DISCOVERED TO BE THE WEMAC BOOST FAN WHICH HAD BURNED ITSELF OUT, CAUSING THE SMOKE. ALL OTHER SYS WERE CHKED AND FOUND NORMAL. THE WEMAC BOOST FAN WAS THEN SECURED AND THE ACFT WAS RELEASED TO RETURN TO MLI. WE HAD NO FURTHER PROBS. NOTE: THIS FLT WAS AN EMPTY (NO PAX) FLT AT TIME OF OCCURRENCE.

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.