Narrative:

Departed IFR from mount comfort airport (indianapolis), filed for 4000 ft. Heavy icing at 4000 ft, indianapolis controller suggested 5000 ft would be better as tops were below 5000 ft. I climbed to 5000 ft, and was in between layers. Handed off to grissom approach, all is well between layers. Tops started to get higher, in and out of tops, getting more ice. I climbed to 5200 ft and stopped climb. Still just below tops, asked grissom for a block between 5000 ft and 6000 ft. Grissom approved the block. I then moved up to 5500 ft and stayed there. Handed off to chicago center. The center operator proceeded to tell me how I climbed without permission and when on an IFR flight plan I couldn't do that. And that he wasn't sure if grissom was going to report it or not. I thanked him for comments. Sunday 1/xx/92 on a VFR trip to louisville, I overflew grissom, asked for their telephone number. When I landed at louisville I called and by luck the supervisor on duty was the same one on duty thursday night. She remembered my flight and said she did not have any problems with it and did not make any reports. I thanked her and left it at that. My mode C does read out about 150 ft high, which may have been part of the problem with chicago center. Also there is a delay between the mode C readout from the airplane and the readout the radar operator gets. They should know this, to the center controller it may have looked like a continuous climb on his readout.

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Original NASA ASRS Text

Title: GA SMA PLT IS ACCUSED OF MAKING AN ALTDEV FOR CHANGING ALT WITHIN AN ASSIGNED ALT BLOCK.

Narrative: DEPARTED IFR FROM MOUNT COMFORT ARPT (INDIANAPOLIS), FILED FOR 4000 FT. HVY ICING AT 4000 FT, INDIANAPOLIS CTLR SUGGESTED 5000 FT WOULD BE BETTER AS TOPS WERE BELOW 5000 FT. I CLBED TO 5000 FT, AND WAS IN BTWN LAYERS. HANDED OFF TO GRISSOM APCH, ALL IS WELL BTWN LAYERS. TOPS STARTED TO GET HIGHER, IN AND OUT OF TOPS, GETTING MORE ICE. I CLBED TO 5200 FT AND STOPPED CLB. STILL JUST BELOW TOPS, ASKED GRISSOM FOR A BLOCK BTWN 5000 FT AND 6000 FT. GRISSOM APPROVED THE BLOCK. I THEN MOVED UP TO 5500 FT AND STAYED THERE. HANDED OFF TO CHICAGO CENTER. THE CENTER OPERATOR PROCEEDED TO TELL ME HOW I CLBED WITHOUT PERMISSION AND WHEN ON AN IFR FLT PLAN I COULDN'T DO THAT. AND THAT HE WASN'T SURE IF GRISSOM WAS GOING TO RPT IT OR NOT. I THANKED HIM FOR COMMENTS. SUNDAY 1/XX/92 ON A VFR TRIP TO LOUISVILLE, I OVERFLEW GRISSOM, ASKED FOR THEIR TELEPHONE NUMBER. WHEN I LANDED AT LOUISVILLE I CALLED AND BY LUCK THE SUPVR ON DUTY WAS THE SAME ONE ON DUTY THURSDAY NIGHT. SHE REMEMBERED MY FLT AND SAID SHE DID NOT HAVE ANY PROBLEMS WITH IT AND DID NOT MAKE ANY RPTS. I THANKED HER AND LEFT IT AT THAT. MY MODE C DOES READ OUT ABOUT 150 FT HIGH, WHICH MAY HAVE BEEN PART OF THE PROBLEM WITH CHICAGO CENTER. ALSO THERE IS A DELAY BTWN THE MODE C READOUT FROM THE AIRPLANE AND THE READOUT THE RADAR OPERATOR GETS. THEY SHOULD KNOW THIS, TO THE CENTER CTLR IT MAY HAVE LOOKED LIKE A CONTINUOUS CLB ON HIS READOUT.

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.