Narrative:

While flying an small transport for the aircraft owner to north adams, ma (2b6) for maintenance, this pilot started a VFR descent from 11500 ft approximately 10-12 mi northeast of the pwl VOR. While descending through approximately 5500 ft, it became apparent that continued VFR due to snow and decreased forward visibility was unlikely. At this time a local IFR clearance for an instrument approach to the psf airport was requested from albany approach control with whom the flight had been working for VFR flight following. A clearance was issued to proceed directly to the dxt beacon to maintain 4000 ft and the flight was cleared for the localizer runway 26 at psf. At the time a SIGMET for occasional severe turbulence was in effect. Descending through 4500 ft, the aircraft encountered constant moderate to occasional severe turbulence. To prevent overstressing the airframe, power was reduced at times to flight idle. Even with greatly reduced power, the aircraft was unable to maintain 4000 ft and stay within 10-15 KTS of va. As a result, the aircraft slowly climbed to 4800 ft at which point the albany approach controller asked the aircraft's altitude. I replied '4800 ft, we're just trying to stay out of the bumps' or something to that effect. No other mention was made by albany approach and I was able to cancel IFR inbound on the localizer passing 3200 ft and continue VFR to 2b6. My concern is that I was unable to maintain an assigned altitude and was so busy trying to stay in control of the aircraft that I did not advise albany approach before I had to be asked by the controller. Also, if any action is to be taken by the FAA, I want to make it clear that it was I and not the registered owner/pilot flying on this occasion.

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Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION FROM ASSIGNED. INFLT ENCOUNTER WITH TURB.

Narrative: WHILE FLYING AN SMT FOR THE ACFT OWNER TO N ADAMS, MA (2B6) FOR MAINT, THIS PLT STARTED A VFR DSCNT FROM 11500 FT APPROX 10-12 MI NE OF THE PWL VOR. WHILE DSNDING THROUGH APPROX 5500 FT, IT BECAME APPARENT THAT CONTINUED VFR DUE TO SNOW AND DECREASED FORWARD VISIBILITY WAS UNLIKELY. AT THIS TIME A LCL IFR CLRNC FOR AN INST APCH TO THE PSF ARPT WAS REQUESTED FROM ALBANY APCH CTL WITH WHOM THE FLT HAD BEEN WORKING FOR VFR FLT FOLLOWING. A CLRNC WAS ISSUED TO PROCEED DIRECTLY TO THE DXT BEACON TO MAINTAIN 4000 FT AND THE FLT WAS CLRED FOR THE LOC RWY 26 AT PSF. AT THE TIME A SIGMET FOR OCCASIONAL SEVERE TURB WAS IN EFFECT. DSNDING THROUGH 4500 FT, THE ACFT ENCOUNTERED CONSTANT MODERATE TO OCCASIONAL SEVERE TURB. TO PREVENT OVERSTRESSING THE AIRFRAME, PWR WAS REDUCED AT TIMES TO FLT IDLE. EVEN WITH GREATLY REDUCED PWR, THE ACFT WAS UNABLE TO MAINTAIN 4000 FT AND STAY WITHIN 10-15 KTS OF VA. AS A RESULT, THE ACFT SLOWLY CLBED TO 4800 FT AT WHICH POINT THE ALBANY APCH CTLR ASKED THE ACFT'S ALT. I REPLIED '4800 FT, WE'RE JUST TRYING TO STAY OUT OF THE BUMPS' OR SOMETHING TO THAT EFFECT. NO OTHER MENTION WAS MADE BY ALBANY APCH AND I WAS ABLE TO CANCEL IFR INBOUND ON THE LOC PASSING 3200 FT AND CONTINUE VFR TO 2B6. MY CONCERN IS THAT I WAS UNABLE TO MAINTAIN AN ASSIGNED ALT AND WAS SO BUSY TRYING TO STAY IN CTL OF THE ACFT THAT I DID NOT ADVISE ALBANY APCH BEFORE I HAD TO BE ASKED BY THE CTLR. ALSO, IF ANY ACTION IS TO BE TAKEN BY THE FAA, I WANT TO MAKE IT CLR THAT IT WAS I AND NOT THE REGISTERED OWNER/PLT FLYING ON THIS OCCASION.

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.