Narrative:

We left lci headed for ipt. WX was good with clouds forecast to be 3000-4000 ft scattered, broken. Ipt (williamsport, PA) was report clear. The clouds did form near the mountain, at 6500 ft, VFR was difficult to maintain. We climbed to 8500 ft. Soon the clouds began to get close even at that altitude, so I asked for and got IFR clearance to williamsport direct at 9000 ft. Shortly after receiving the clearance the controller called us and asked us our altitude. I was not quite 9100 ft so I reported 9000 ft. He responded by saying he showed us 300 ft high, and gave us the altimeter setting again. To my shock it was off over 100 ft. Flying from the right seat the altimeter adjustment is completely blocked. 1 of 3 things happened: 1) the student incorrectly set the altimeter in the first place. (The student has about 350 hours on that airplane and about 500 total), 2) he set it correct, but developed a bad habit of changing it when he hears a new setting. He may have reached over and changed it when I was scanning for traffic. Possibility 3) is that the transponder/mode C had just been worked on and was bonkers for just a few mins. It gave us trouble the rest of the trip by occasionally disappearing from the scope. This was a student that was very new to me and an aircraft that was just as new. I was not aware that the kollsman window was invisible from the right seat. Even leaning way over did not help. The student was too new to me to have an educated guess as to predict his reactions. I can promise I will be more careful in the future.

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Original NASA ASRS Text

Title: RPTR OFF ASSIGNED ALT AS PER WRONG ALTIMETER SETTING.

Narrative: WE LEFT LCI HEADED FOR IPT. WX WAS GOOD WITH CLOUDS FORECAST TO BE 3000-4000 FT SCATTERED, BROKEN. IPT (WILLIAMSPORT, PA) WAS RPT CLR. THE CLOUDS DID FORM NEAR THE MOUNTAIN, AT 6500 FT, VFR WAS DIFFICULT TO MAINTAIN. WE CLBED TO 8500 FT. SOON THE CLOUDS BEGAN TO GET CLOSE EVEN AT THAT ALT, SO I ASKED FOR AND GOT IFR CLRNC TO WILLIAMSPORT DIRECT AT 9000 FT. SHORTLY AFTER RECEIVING THE CLRNC THE CTLR CALLED US AND ASKED US OUR ALT. I WAS NOT QUITE 9100 FT SO I RPTED 9000 FT. HE RESPONDED BY SAYING HE SHOWED US 300 FT HIGH, AND GAVE US THE ALTIMETER SETTING AGAIN. TO MY SHOCK IT WAS OFF OVER 100 FT. FLYING FROM THE R SEAT THE ALTIMETER ADJUSTMENT IS COMPLETELY BLOCKED. 1 OF 3 THINGS HAPPENED: 1) THE STUDENT INCORRECTLY SET THE ALTIMETER IN THE FIRST PLACE. (THE STUDENT HAS ABOUT 350 HRS ON THAT AIRPLANE AND ABOUT 500 TOTAL), 2) HE SET IT CORRECT, BUT DEVELOPED A BAD HABIT OF CHANGING IT WHEN HE HEARS A NEW SETTING. HE MAY HAVE REACHED OVER AND CHANGED IT WHEN I WAS SCANNING FOR TFC. POSSIBILITY 3) IS THAT THE XPONDER/MODE C HAD JUST BEEN WORKED ON AND WAS BONKERS FOR JUST A FEW MINS. IT GAVE US TROUBLE THE REST OF THE TRIP BY OCCASIONALLY DISAPPEARING FROM THE SCOPE. THIS WAS A STUDENT THAT WAS VERY NEW TO ME AND AN ACFT THAT WAS JUST AS NEW. I WAS NOT AWARE THAT THE KOLLSMAN WINDOW WAS INVISIBLE FROM THE R SEAT. EVEN LEANING WAY OVER DID NOT HELP. THE STUDENT WAS TOO NEW TO ME TO HAVE AN EDUCATED GUESS AS TO PREDICT HIS REACTIONS. I CAN PROMISE I WILL BE MORE CAREFUL IN THE FUTURE.

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.