IFR PA34 en route was advised by ATC of incorrect altitude.

Attributes
ACN	588070
Time
Date	200307
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : fnt.vortac
State Reference	MI
Altitude	msl bound lower : 3500 msl bound upper : 4000
Environment
Flight Conditions	IMC
Weather Elements	Thunderstorm Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc artcc : zmp.artcc
Operator	general aviation : personal
Make Model Name	PA-34-220T Turbo Seneca III
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude descent : approach
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Experience	flight time last 90 days : 35 flight time total : 1650 flight time type : 35
ASRS Report	588070
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued advisory flight crew : became reoriented flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Weather Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Departing charlevoix (cvx) I was vectored to the east, toward WX. There were towering cumulus present following passage of convective activity. This was not the usual route to ptk, but I was advised that I would have to go east to avoid the military airspace and due to traffic saturation. At 13000 ft it appeared that I would enter the tops of the towering cumulus. I requested a block altitude to 14000 ft, but this was denied. The controllers were quite busy. It did not appear that a left or right deviation would be helpful. Upon entry into the clouds I encountered moderate to severe turbulence and ice. Deviations from assigned altitude were between 200-500 ft due to up and downdrafts. This lasted perhaps 1 min. Also, over flint (fnt) at assigned altitude of 4000 ft the controller showed me at 3500 ft. A check of my altimeter showed that I was at 30.1 and flint advised its altimeter was 29.82 inches. This caused me to be 400 ft low and I corrected immediately. I believe I had not correctly set my altimeter in charlevoix prior to takeoff.

Original NASA ASRS Text

Title: IFR PA34 ENRTE WAS ADVISED BY ATC OF INCORRECT ALT.

Narrative: DEPARTING CHARLEVOIX (CVX) I WAS VECTORED TO THE E, TOWARD WX. THERE WERE TOWERING CUMULUS PRESENT FOLLOWING PASSAGE OF CONVECTIVE ACTIVITY. THIS WAS NOT THE USUAL RTE TO PTK, BUT I WAS ADVISED THAT I WOULD HAVE TO GO E TO AVOID THE MIL AIRSPACE AND DUE TO TFC SATURATION. AT 13000 FT IT APPEARED THAT I WOULD ENTER THE TOPS OF THE TOWERING CUMULUS. I REQUESTED A BLOCK ALT TO 14000 FT, BUT THIS WAS DENIED. THE CTLRS WERE QUITE BUSY. IT DID NOT APPEAR THAT A L OR R DEV WOULD BE HELPFUL. UPON ENTRY INTO THE CLOUDS I ENCOUNTERED MODERATE TO SEVERE TURB AND ICE. DEVS FROM ASSIGNED ALT WERE BTWN 200-500 FT DUE TO UP AND DOWNDRAFTS. THIS LASTED PERHAPS 1 MIN. ALSO, OVER FLINT (FNT) AT ASSIGNED ALT OF 4000 FT THE CTLR SHOWED ME AT 3500 FT. A CHK OF MY ALTIMETER SHOWED THAT I WAS AT 30.1 AND FLINT ADVISED ITS ALTIMETER WAS 29.82 INCHES. THIS CAUSED ME TO BE 400 FT LOW AND I CORRECTED IMMEDIATELY. I BELIEVE I HAD NOT CORRECTLY SET MY ALTIMETER IN CHARLEVOIX PRIOR TO TKOF.

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.