Narrative:

Proceeding eastbound on victor 58 just west of williamsport (ipt), I noticed I was accumulating some rime ice at 7000 ft. I queried the ZNY controller for the williamsport WX, and based on the information I received, I requested 6000 ft to get out of the clouds and out of the icing. I was cleared to 6000 ft. I then continued toward lake henry on victor 58, occasionally encountering some moderate turbulence. Between williamsport and lake henry, it became dark. We were in light snow. On arriving closer to lake henry, we again became IMC. About 5 mins before arriving at lake henry, I noticed the airspeed beginning to drop off very slowly. I also noticed a slight increase in the accumulation of ice. Pitot heat was on. As we drew closer to lake henry, I decided to execute a precautionary landing at wilkes- barre, due to the increased ice and also because the airspeed was beginning to drop off signifying to me a degradation in power output and perhaps an increase in stall speed. I communicated these intentions to wilkes- barre approach. Wilkes-barre cleared me to descend to 3300 ft and to intercept the localizer. Once I was level at 3300 ft, the airspeed continued to drop. It was now at 60 KTS. I was still left of the localizer. Before I intercepted the GS I realized I could not maintain airspeed in level flight. Fearful of a stall, I departed my assigned altitude and simultaneously observed, slightly to the left of the aircraft, a lighted area. I elected to circle the lighted area because I realized that this was mountainous terrain and I had departed from my assigned altitude. The controller then instructed me to execute a missed approach, to fly a heading of 040 degrees and maintain 4000 ft. Based on my judgement that the aircraft was imminently close to a stall with all power available, I declined to climb. Instead, I requested a vector toward the airport. The controller assigned me a heading, and I attempted to maintain altitude. The controller instructed me to check my pitot heat, which I did -- it was on. The airspeed then dropped to 0. At that point, I diagnosed the problem as an airspeed indication malfunction. I disregarded the airspeed indication. When I was approximately 1/2 mi from the airport, I observed the REIL lights and landed on runway 28 in light snow. Once on the ground, on departing the aircraft, I observed the pitot tube -- it was encased in ice. I then returned to the cockpit, turned on the master and turned on the pitot heat to confirm the heater was malfunctioning.

Related reports:

Google
 

Original NASA ASRS Text

Title: PLT OF SMA ACFT DID NOT MAINTAIN ASSIGNED ALT DURING APCH VECTOR DUE ACFT'S LACK OF PERFORMANCE DUE TO INFLT ICING CONDITIONS.

Narrative: PROCEEDING EBOUND ON VICTOR 58 JUST W OF WILLIAMSPORT (IPT), I NOTICED I WAS ACCUMULATING SOME RIME ICE AT 7000 FT. I QUERIED THE ZNY CTLR FOR THE WILLIAMSPORT WX, AND BASED ON THE INFO I RECEIVED, I REQUESTED 6000 FT TO GET OUT OF THE CLOUDS AND OUT OF THE ICING. I WAS CLRED TO 6000 FT. I THEN CONTINUED TOWARD LAKE HENRY ON VICTOR 58, OCCASIONALLY ENCOUNTERING SOME MODERATE TURB. BTWN WILLIAMSPORT AND LAKE HENRY, IT BECAME DARK. WE WERE IN LIGHT SNOW. ON ARRIVING CLOSER TO LAKE HENRY, WE AGAIN BECAME IMC. ABOUT 5 MINS BEFORE ARRIVING AT LAKE HENRY, I NOTICED THE AIRSPD BEGINNING TO DROP OFF VERY SLOWLY. I ALSO NOTICED A SLIGHT INCREASE IN THE ACCUMULATION OF ICE. PITOT HEAT WAS ON. AS WE DREW CLOSER TO LAKE HENRY, I DECIDED TO EXECUTE A PRECAUTIONARY LNDG AT WILKES- BARRE, DUE TO THE INCREASED ICE AND ALSO BECAUSE THE AIRSPD WAS BEGINNING TO DROP OFF SIGNIFYING TO ME A DEGRADATION IN PWR OUTPUT AND PERHAPS AN INCREASE IN STALL SPD. I COMMUNICATED THESE INTENTIONS TO WILKES- BARRE APCH. WILKES-BARRE CLRED ME TO DSND TO 3300 FT AND TO INTERCEPT THE LOC. ONCE I WAS LEVEL AT 3300 FT, THE AIRSPD CONTINUED TO DROP. IT WAS NOW AT 60 KTS. I WAS STILL L OF THE LOC. BEFORE I INTERCEPTED THE GS I REALIZED I COULD NOT MAINTAIN AIRSPD IN LEVEL FLT. FEARFUL OF A STALL, I DEPARTED MY ASSIGNED ALT AND SIMULTANEOUSLY OBSERVED, SLIGHTLY TO THE L OF THE ACFT, A LIGHTED AREA. I ELECTED TO CIRCLE THE LIGHTED AREA BECAUSE I REALIZED THAT THIS WAS MOUNTAINOUS TERRAIN AND I HAD DEPARTED FROM MY ASSIGNED ALT. THE CTLR THEN INSTRUCTED ME TO EXECUTE A MISSED APCH, TO FLY A HDG OF 040 DEGS AND MAINTAIN 4000 FT. BASED ON MY JUDGEMENT THAT THE ACFT WAS IMMINENTLY CLOSE TO A STALL WITH ALL PWR AVAILABLE, I DECLINED TO CLB. INSTEAD, I REQUESTED A VECTOR TOWARD THE ARPT. THE CTLR ASSIGNED ME A HDG, AND I ATTEMPTED TO MAINTAIN ALT. THE CTLR INSTRUCTED ME TO CHK MY PITOT HEAT, WHICH I DID -- IT WAS ON. THE AIRSPD THEN DROPPED TO 0. AT THAT POINT, I DIAGNOSED THE PROB AS AN AIRSPD INDICATION MALFUNCTION. I DISREGARDED THE AIRSPD INDICATION. WHEN I WAS APPROX 1/2 MI FROM THE ARPT, I OBSERVED THE REIL LIGHTS AND LANDED ON RWY 28 IN LIGHT SNOW. ONCE ON THE GND, ON DEPARTING THE ACFT, I OBSERVED THE PITOT TUBE -- IT WAS ENCASED IN ICE. I THEN RETURNED TO THE COCKPIT, TURNED ON THE MASTER AND TURNED ON THE PITOT HEAT TO CONFIRM THE HEATER WAS MALFUNCTIONING.

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.