An small aircraft pilot developed carburetor ice.

Attributes
ACN	262929
Time
Date	199401
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : mob
State Reference	AL
Altitude	msl bound lower : 4000 msl bound upper : 6000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other descent other
Route In Use	enroute airway : zhu
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : instrument pilot : commercial
Experience	flight time last 90 days : 35 flight time total : 2490 flight time type : 830
ASRS Report	262929
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : published procedure other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : provided flight assist flight crew : exited adverse environment flight crew : overcame equipment problem other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was en route from tallahassee, fl, to new orleans (lakefront) at my assigned altitude of 6000 ft when I noticed a drop in manifold pressure. I was in IMC with moderate rain with an outside air temperature of 48 degrees F. As the drop in manifold pressure began to cause a loss of altitude, I activated carburetor heat. At an altitude of about 5600 ft, my manifold pressure began to increase to normal. ATC called about my altitude and assigned a new altitude of 4000 ft at that time. I maintained carburetor heat until landing and had no further problems with obvious carburetor icing.

Original NASA ASRS Text

Title: AN SMA PLT DEVELOPED CARB ICE.

Narrative: I WAS ENRTE FROM TALLAHASSEE, FL, TO NEW ORLEANS (LAKEFRONT) AT MY ASSIGNED ALT OF 6000 FT WHEN I NOTICED A DROP IN MANIFOLD PRESSURE. I WAS IN IMC WITH MODERATE RAIN WITH AN OUTSIDE AIR TEMP OF 48 DEGS F. AS THE DROP IN MANIFOLD PRESSURE BEGAN TO CAUSE A LOSS OF ALT, I ACTIVATED CARB HEAT. AT AN ALT OF ABOUT 5600 FT, MY MANIFOLD PRESSURE BEGAN TO INCREASE TO NORMAL. ATC CALLED ABOUT MY ALT AND ASSIGNED A NEW ALT OF 4000 FT AT THAT TIME. I MAINTAINED CARB HEAT UNTIL LNDG AND HAD NO FURTHER PROBS WITH OBVIOUS CARB ICING.

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.