Narrative:

After takeoff and entering the clouds, the airspeed began to bleed off quickly. After checking the other instruments, the altitude was steady at 1900 ft MSL and the vsi at '0' but the power was at climb and the attitude indicator was showing pitch up. I checked the copilot instruments and they showed the same thing. Gear and flaps were retracted and the aircraft showed no signs of stalling. I had already turned on both pitot heats and the temperature was 48 degrees F, so ice was no factor. I continued the climb due to being IMC and obstacles. At this point I reached for the alternate static source and turned it on. This caused the altimeter to jump to 4300 ft MSL. I had been assigned 3000 ft MSL and 4000 ft MSL 10 mins after departure, but had not received clearance to 4000 ft. The heading was 170 degrees. 10 mins had not gone by since departure. Departure control asked my altitude a couple of times and I told them that it showed 1900 ft the first time and they said it checked. When they asked the second time was just after I opened the alternate static source. 4300 ft checked with the mode C and I was told to maintain 4000 ft, which I did. After some time en route, I closed the alternate static source and the primary source was fine. Upon landing at my destination, I checked the static ports and found evidence of tape over the ports. It was put there during cleaning to keep them clear, but someone forgot to remove the tape, and I failed to see it on my preflight, partly due to doing it in the dark and the tape was red -- the same color red as the aircraft stripe that runs across the port. The preflight was obviously not thorough enough and should have been done with a flashlight. The alternate static source should have been opened at the same time the pitot heat was turned on. That would have stopped the altitude incursion.

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Original NASA ASRS Text

Title: RPTR LOSES ALTIMETER AND VERT SPD IN IMC AND OVERSHOOTS ASSIGNED ALT BY 1300 FT.

Narrative: AFTER TKOF AND ENTERING THE CLOUDS, THE AIRSPD BEGAN TO BLEED OFF QUICKLY. AFTER CHKING THE OTHER INSTS, THE ALT WAS STEADY AT 1900 FT MSL AND THE VSI AT '0' BUT THE PWR WAS AT CLB AND THE ATTITUDE INDICATOR WAS SHOWING PITCH UP. I CHKED THE COPLT INSTS AND THEY SHOWED THE SAME THING. GEAR AND FLAPS WERE RETRACTED AND THE ACFT SHOWED NO SIGNS OF STALLING. I HAD ALREADY TURNED ON BOTH PITOT HEATS AND THE TEMP WAS 48 DEGS F, SO ICE WAS NO FACTOR. I CONTINUED THE CLB DUE TO BEING IMC AND OBSTACLES. AT THIS POINT I REACHED FOR THE ALTERNATE STATIC SOURCE AND TURNED IT ON. THIS CAUSED THE ALTIMETER TO JUMP TO 4300 FT MSL. I HAD BEEN ASSIGNED 3000 FT MSL AND 4000 FT MSL 10 MINS AFTER DEP, BUT HAD NOT RECEIVED CLRNC TO 4000 FT. THE HDG WAS 170 DEGS. 10 MINS HAD NOT GONE BY SINCE DEP. DEP CTL ASKED MY ALT A COUPLE OF TIMES AND I TOLD THEM THAT IT SHOWED 1900 FT THE FIRST TIME AND THEY SAID IT CHKED. WHEN THEY ASKED THE SECOND TIME WAS JUST AFTER I OPENED THE ALTERNATE STATIC SOURCE. 4300 FT CHKED WITH THE MODE C AND I WAS TOLD TO MAINTAIN 4000 FT, WHICH I DID. AFTER SOME TIME ENRTE, I CLOSED THE ALTERNATE STATIC SOURCE AND THE PRIMARY SOURCE WAS FINE. UPON LNDG AT MY DEST, I CHKED THE STATIC PORTS AND FOUND EVIDENCE OF TAPE OVER THE PORTS. IT WAS PUT THERE DURING CLEANING TO KEEP THEM CLR, BUT SOMEONE FORGOT TO REMOVE THE TAPE, AND I FAILED TO SEE IT ON MY PREFLT, PARTLY DUE TO DOING IT IN THE DARK AND THE TAPE WAS RED -- THE SAME COLOR RED AS THE ACFT STRIPE THAT RUNS ACROSS THE PORT. THE PREFLT WAS OBVIOUSLY NOT THOROUGH ENOUGH AND SHOULD HAVE BEEN DONE WITH A FLASHLIGHT. THE ALTERNATE STATIC SOURCE SHOULD HAVE BEEN OPENED AT THE SAME TIME THE PITOT HEAT WAS TURNED ON. THAT WOULD HAVE STOPPED THE ALT INCURSION.

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.