Light single engine aircraft pilot descends through cleared altitude due to static port icing in ind...

Attributes
ACN	428524
Time
Date	199902
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ind.airport
State Reference	IN
Altitude	msl bound lower : 4500 msl bound upper : 5000
Environment
Flight Conditions	IMC
Weather Elements	Ice
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ind.tracon
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Navigation In Use	other Other other vortac
Flight Phase	cruise : enroute altitude change
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	other
Function	observation : passenger
Qualification	pilot : cfi pilot : commercial pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 1100 flight time type : 50
ASRS Report	428524
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot inflight encounter : weather non adherence : clearance
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued advisory flight crew : overcame equipment problem flight crew : returned to original clearance
Consequence	Other
Supplementary
Problem Areas	Flight Crew Human Performance Weather
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

Cruising at 9000 ft, began inadvertently accreting ice. Requested a descent to 5000 ft. In the descent, the static ports seemingly iced over causing altimeter to freeze at 5000 ft. Once the static source was restored, altimeter needle jumped to 4500 ft and we were then alerted by ATC. After leveling at 5000 ft with restored system, flight was uneventful. The icing conditions only produced a trace of rime ice accretion. The icing conditions were not forecast for our route of flight.

Original NASA ASRS Text

Title: LIGHT SINGLE ENG ACFT PLT DSNDS THROUGH CLRED ALT DUE TO STATIC PORT ICING IN IND AIRSPACE.

Narrative: CRUISING AT 9000 FT, BEGAN INADVERTENTLY ACCRETING ICE. REQUESTED A DSCNT TO 5000 FT. IN THE DSCNT, THE STATIC PORTS SEEMINGLY ICED OVER CAUSING ALTIMETER TO FREEZE AT 5000 FT. ONCE THE STATIC SOURCE WAS RESTORED, ALTIMETER NEEDLE JUMPED TO 4500 FT AND WE WERE THEN ALERTED BY ATC. AFTER LEVELING AT 5000 FT WITH RESTORED SYS, FLT WAS UNEVENTFUL. THE ICING CONDITIONS ONLY PRODUCED A TRACE OF RIME ICE ACCRETION. THE ICING CONDITIONS WERE NOT FORECAST FOR OUR RTE OF FLT.

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.

Light single engine aircraft pilot descends through cleared altitude due to static port icing in ind airspace.