BE1900 flight crew has smoke in the cockpit during cruise; descent.

Attributes
ACN	686534
Time
Date	200602
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zzz.tracon
State Reference	US
Altitude	msl single value : 16000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	Beech 1900
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : zzz
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 160 flight time total : 3100 flight time type : 2310
ASRS Report	686534
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 5700 flight time type : 4800
ASRS Report	686535
Events
Anomaly	aircraft equipment problem : critical other anomaly
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist flight crew : landed in emergency condition flight crew : landed as precaution flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

We were descending out of FL200 for 15000 ft. Given by ATC; conditions were mostly IMC. All anti-ice equipment on. I began to smell something burning and notified captain. Captain agreed. Approximately 7 seconds later; passing through approximately 16000 ft; smoke started coming through captain's control column. Captain immediately turned off all anti-ice equipment except engine anti-ice and put on his oxygen mask. I continued to fly the aircraft. The smoke began to immediately dissipate. Captain notified ATC; asked for a lower altitude and direct ZZZ1 without delay. We received a heading for direct ZZZ1 and 10000 ft for the altitude. ATC declared an emergency. No further indications of smoke or fire were present. It seems the captain's immediate reaction to shut off anti-ice equipment alleviated further damage to the aircraft. We were VMC passing through approximately 15500 ft. We ran all pertinent checklists; discussed landing options including speed for flaps 0 degree landing if smoke returned. In ZZZ1 we landed flaps 0 degrees; taxied and parked without further incident. Supplemental information from acn 686535: the first officer called for the checklist and he went through them all. He discussed items that were relevant to our situation and options we had if the problem returned; including other possible landing sites. Several wires on the captain's side were burned and melted; including one wire that went across to the first officer's side. The problem was traced to a short in the windshield ice wiring.

Original NASA ASRS Text

Title: BE1900 FLT CREW HAS SMOKE IN THE COCKPIT DURING CRUISE; DSCNT.

Narrative: WE WERE DSNDING OUT OF FL200 FOR 15000 FT. GIVEN BY ATC; CONDITIONS WERE MOSTLY IMC. ALL ANTI-ICE EQUIP ON. I BEGAN TO SMELL SOMETHING BURNING AND NOTIFIED CAPT. CAPT AGREED. APPROX 7 SECONDS LATER; PASSING THROUGH APPROX 16000 FT; SMOKE STARTED COMING THROUGH CAPT'S CTL COLUMN. CAPT IMMEDIATELY TURNED OFF ALL ANTI-ICE EQUIP EXCEPT ENG ANTI-ICE AND PUT ON HIS OXYGEN MASK. I CONTINUED TO FLY THE ACFT. THE SMOKE BEGAN TO IMMEDIATELY DISSIPATE. CAPT NOTIFIED ATC; ASKED FOR A LOWER ALT AND DIRECT ZZZ1 WITHOUT DELAY. WE RECEIVED A HDG FOR DIRECT ZZZ1 AND 10000 FT FOR THE ALT. ATC DECLARED AN EMER. NO FURTHER INDICATIONS OF SMOKE OR FIRE WERE PRESENT. IT SEEMS THE CAPT'S IMMEDIATE REACTION TO SHUT OFF ANTI-ICE EQUIP ALLEVIATED FURTHER DAMAGE TO THE ACFT. WE WERE VMC PASSING THROUGH APPROX 15500 FT. WE RAN ALL PERTINENT CHKLISTS; DISCUSSED LNDG OPTIONS INCLUDING SPD FOR FLAPS 0 DEG LNDG IF SMOKE RETURNED. IN ZZZ1 WE LANDED FLAPS 0 DEGS; TAXIED AND PARKED WITHOUT FURTHER INCIDENT. SUPPLEMENTAL INFO FROM ACN 686535: THE FO CALLED FOR THE CHKLIST AND HE WENT THROUGH THEM ALL. HE DISCUSSED ITEMS THAT WERE RELEVANT TO OUR SITUATION AND OPTIONS WE HAD IF THE PROB RETURNED; INCLUDING OTHER POSSIBLE LNDG SITES. SEVERAL WIRES ON THE CAPT'S SIDE WERE BURNED AND MELTED; INCLUDING ONE WIRE THAT WENT ACROSS TO THE FO'S SIDE. THE PROB WAS TRACED TO A SHORT IN THE WINDSHIELD ICE WIRING.

Data retrieved from NASA's ASRS site as of January 2009 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.