An MU2 marq on initial climb at 2000 ft declared an emergency and diverted due to smoke in the cabin...

Attributes
ACN	418969
Time
Date	199811
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 2000 msl bound upper : 2500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : atl tower : dtw
Operator	common carrier : air carrier
Make Model Name	MU-2B 60 Marquise
Operating Under FAR Part	Part 135
Flight Phase	climbout : initial other other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 150 flight time total : 2500 flight time type : 150
ASRS Report	418969
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : detected after the fact other
Consequence	Other

Narrative:

The problem occurred due to the environmental system. The motor that turns the valve to duct heat in was open more than suspected, but due to the power being at flight idle was not a problem. At takeoff when the power was set full, the temperature increased to such a temperature that it began to melt and overheat the duct work of the plane. After takeoff and into the climb out the smoke filled the cabin. While trying to determine the problem, I informed approach of the situation and began to vacate the cabin of smoke. The controller vectored me around for an approach (ILS runway 26R) after landing and maintaining control of the situation I returned to FBO, exited the cabin through the front window and walked around to open the rear cabin door to determine if there was any fire of which there was not. After investigating the problem and determined that the motor turning the valve was slower than normal I gave it more time to close and continued the flight without a problem. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a mitsubishi MU2 marquise pwred with aireserch tpe 331-5-252M turboprop engines. The reporter stated the aircraft has an air cycle environmental system using engine bleed air and was not aware of the slow movement of the hot air valve. The reporter stated the valve was not replaced as this was considered normal operation.

Original NASA ASRS Text

Title: AN MU2 MARQ ON INITIAL CLB AT 2000 FT DECLARED AN EMER AND DIVERTED DUE TO SMOKE IN THE CABIN CAUSED BY A SLOW OPERATING HEAT CTL VALVE OVERHEATING FIBERGLAS DUCTING.

Narrative: THE PROB OCCURRED DUE TO THE ENVIRONMENTAL SYS. THE MOTOR THAT TURNS THE VALVE TO DUCT HEAT IN WAS OPEN MORE THAN SUSPECTED, BUT DUE TO THE PWR BEING AT FLT IDLE WAS NOT A PROB. AT TKOF WHEN THE PWR WAS SET FULL, THE TEMP INCREASED TO SUCH A TEMP THAT IT BEGAN TO MELT AND OVERHEAT THE DUCT WORK OF THE PLANE. AFTER TKOF AND INTO THE CLBOUT THE SMOKE FILLED THE CABIN. WHILE TRYING TO DETERMINE THE PROB, I INFORMED APCH OF THE SIT AND BEGAN TO VACATE THE CABIN OF SMOKE. THE CTLR VECTORED ME AROUND FOR AN APCH (ILS RWY 26R) AFTER LNDG AND MAINTAINING CTL OF THE SIT I RETURNED TO FBO, EXITED THE CABIN THROUGH THE FRONT WINDOW AND WALKED AROUND TO OPEN THE REAR CABIN DOOR TO DETERMINE IF THERE WAS ANY FIRE OF WHICH THERE WAS NOT. AFTER INVESTIGATING THE PROB AND DETERMINED THAT THE MOTOR TURNING THE VALVE WAS SLOWER THAN NORMAL I GAVE IT MORE TIME TO CLOSE AND CONTINUED THE FLT WITHOUT A PROB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A MITSUBISHI MU2 MARQUISE PWRED WITH AIRESERCH TPE 331-5-252M TURBOPROP ENGS. THE RPTR STATED THE ACFT HAS AN AIR CYCLE ENVIRONMENTAL SYS USING ENG BLEED AIR AND WAS NOT AWARE OF THE SLOW MOVEMENT OF THE HOT AIR VALVE. THE RPTR STATED THE VALVE WAS NOT REPLACED AS THIS WAS CONSIDERED NORMAL OP.

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.

An MU2 marq on initial climb at 2000 ft declared an emergency and diverted due to smoke in the cabin caused by a slow operating heat control valve overheating fiberglas ducting.