GA small aircraft suspected pitot static system ice.

Attributes
ACN	141454
Time
Date	199004
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cle
State Reference	OH
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cle
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 50 flight time total : 8500 flight time type : 75
ASRS Report	141454
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After level-off at 4000', assigned IFR altitude and IMC pitot heat had been placed on. Approximately 5 mins had passed and signs of airframe ice were noted. The altimeter/airspeed and vertical speed indicator started to fluctuate. Assuming the pitot heat system to be inoperative, I selected the alternate static source. At that time both the altimeter and vertical speed stabilized and I confirmed my altitude with radar mode C. The airspeed indicator seemed to be in error. I continued the flight to destination and landed west/O incident. A request was made to inspect the pitot static system and the heat element.

Original NASA ASRS Text

Title: GA SMA SUSPECTED PITOT STATIC SYSTEM ICE.

Narrative: AFTER LEVEL-OFF AT 4000', ASSIGNED IFR ALT AND IMC PITOT HEAT HAD BEEN PLACED ON. APPROX 5 MINS HAD PASSED AND SIGNS OF AIRFRAME ICE WERE NOTED. THE ALTIMETER/AIRSPD AND VERTICAL SPD INDICATOR STARTED TO FLUCTUATE. ASSUMING THE PITOT HEAT SYS TO BE INOPERATIVE, I SELECTED THE ALTERNATE STATIC SOURCE. AT THAT TIME BOTH THE ALTIMETER AND VERT SPD STABILIZED AND I CONFIRMED MY ALT WITH RADAR MODE C. THE AIRSPD INDICATOR SEEMED TO BE IN ERROR. I CONTINUED THE FLT TO DEST AND LANDED W/O INCIDENT. A REQUEST WAS MADE TO INSPECT THE PITOT STATIC SYS AND THE HEAT ELEMENT.

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.