Narrative:

I departed direct to gnb; under VFR flight following. En route I received VFR flight following advisories from gray approach; ZAB; amarillo approach; and ZDV. While I was in deteriorating VMC west of fremont (16V); ZDV provided VFR course guidance around a thunderstorm and reported gnb in VMC. Due to continuing deterioration of VMC; I requested in-flight IFR; which was provided by ZDV with a direct course to gnb at an IFR flight level. At approximately the dobee intersection; I reported to ZDV that I was in VMC with the gnb beacon in sight and requested VFR and go to advisory frequency. ZDV responded with a transmission regarding cancellation of IFR clearance and going to advisory frequency; which I read back. I inadvertently interpreted the transmission as automatic to cancel IFR; so I did not initiate further communication with ZDV. I proceeded to gnb in VMC under presumed VFR; and landed without incident. My failure to close my IFR flight plan was not deliberate. Upon my return home I was surprised to find a message that the FAA at ZDV was filing a pilot deviation report for failure to close my flight plan. The filing agent has advised me that ZDV provided instructions for cancelling IFR; and did not authorize cancellation of IFR. I understand now that this is correct; and that there was a miscom. I realize not that instead of requesting 'VFR;' I should have requested 'cancellation of IFR;' and also that I should have listened for ZDV to report 'IFR cancelled;' if I was to assume IFR was cancelled. I also should have established a better mental transition to IFR in spite of the three plus hours of VFR flight that preceded initiation IFR.

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Original NASA ASRS Text

Title: A LIGHT PLANE PILOT FAILED TO CANCEL HIS IFR FLIGHT PLAN.

Narrative: I DEPARTED DIRECT TO GNB; UNDER VFR FLT FOLLOWING. ENRTE I RECEIVED VFR FLT FOLLOWING ADVISORIES FROM GRAY APCH; ZAB; AMARILLO APCH; AND ZDV. WHILE I WAS IN DETERIORATING VMC WEST OF FREMONT (16V); ZDV PROVIDED VFR COURSE GUIDANCE AROUND A TSTM AND REPORTED GNB IN VMC. DUE TO CONTINUING DETERIORATION OF VMC; I REQUESTED INFLT IFR; WHICH WAS PROVIDED BY ZDV WITH A DIRECT COURSE TO GNB AT AN IFR FLT LEVEL. AT APPROX THE DOBEE INTXN; I REPORTED TO ZDV THAT I WAS IN VMC WITH THE GNB BEACON IN SIGHT AND REQUESTED VFR AND GO TO ADVISORY FREQ. ZDV RESPONDED WITH A TRANSMISSION REGARDING CANCELLATION OF IFR CLRNC AND GOING TO ADVISORY FREQ; WHICH I READ BACK. I INADVERTENTLY INTERPRETED THE TRANSMISSION AS AUTO TO CANCEL IFR; SO I DID NOT INITIATE FURTHER COM WITH ZDV. I PROCEEDED TO GNB IN VMC UNDER PRESUMED VFR; AND LANDED WITHOUT INCIDENT. MY FAILURE TO CLOSE MY IFR FLT PLAN WAS NOT DELIBERATE. UPON MY RETURN HOME I WAS SURPRISED TO FIND A MESSAGE THAT THE FAA AT ZDV WAS FILING A PLT DEV REPORT FOR FAILURE TO CLOSE MY FLT PLAN. THE FILING AGENT HAS ADVISED ME THAT ZDV PROVIDED INSTRUCTIONS FOR CANCELLING IFR; AND DID NOT AUTHORIZE CANCELLATION OF IFR. I UNDERSTAND NOW THAT THIS IS CORRECT; AND THAT THERE WAS A MISCOM. I REALIZE NOT THAT INSTEAD OF REQUESTING 'VFR;' I SHOULD HAVE REQUESTED 'CANCELLATION OF IFR;' AND ALSO THAT I SHOULD HAVE LISTENED FOR ZDV TO REPORT 'IFR CANCELLED;' IF I WAS TO ASSUME IFR WAS CANCELLED. I ALSO SHOULD HAVE ESTABLISHED A BETTER MENTAL TRANSITION TO IFR IN SPITE OF THE THREE PLUS HOURS OF VFR FLT THAT PRECEDED INITIATION IFR.

Data retrieved from NASA's ASRS site as of January 2009 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.