Narrative:

I departed casper, wyoming, on an IFR flight, single pilot to hayden, co. Routing of casper direct cherokee VOR V-26 to celia intersection direct hayden. Approximately 50 NM south of cherokee VOR on V-26, I asked for a lower altitude. I was eventually cleared to 12000' for FL200. In the descent I was told that the hayden airport was closed. I asked center for a vector to intercept the localizer for the ILS runway 10 into hayden because hayden unicom said there was no problem with the airport or the runway and there was no apparent reason for the airport to be closed. Hayden unicom said they would try to contact the airport manager and try to have it opened so I could land. Center then cleared me on a vector to intercept the localizer for the ILS (DME) 10 at hayden. I broke out into VFR conditions as I intercepted the localizer. As I proceeded inbound on the localizer I assumed that I had been cleared for the approach to hayden. At 15 NM DME on the ihdn localizer I started out of 12000' for 9000' which is approved on the approach plate. Center then came back after reporting out of 12000' for 9000' and said I was not cleared for an approach to hayden and to maintain 12000' and hold at the che VOR because the airport was closed. I was already out of 11000' and descending fast. I then cancelled IFR and proceeded VFR to the hayden airport and circled the airport waiting for it to open. This incident could have been prevented if I had verified clearance, listened more closely to center, and followed ATC instructions to the letter and not assumed I was cleared for more than I was.

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Original NASA ASRS Text

Title: CPR SMT ALT DEVIATION EXCURSION FROM CLRNC ALT.

Narrative: I DEPARTED CASPER, WYOMING, ON AN IFR FLT, SINGLE PLT TO HAYDEN, CO. ROUTING OF CASPER DIRECT CHEROKEE VOR V-26 TO CELIA INTXN DIRECT HAYDEN. APPROX 50 NM S OF CHEROKEE VOR ON V-26, I ASKED FOR A LOWER ALT. I WAS EVENTUALLY CLRED TO 12000' FOR FL200. IN THE DSCNT I WAS TOLD THAT THE HAYDEN ARPT WAS CLOSED. I ASKED CENTER FOR A VECTOR TO INTERCEPT THE LOC FOR THE ILS RWY 10 INTO HAYDEN BECAUSE HAYDEN UNICOM SAID THERE WAS NO PROB WITH THE ARPT OR THE RWY AND THERE WAS NO APPARENT REASON FOR THE ARPT TO BE CLOSED. HAYDEN UNICOM SAID THEY WOULD TRY TO CONTACT THE ARPT MGR AND TRY TO HAVE IT OPENED SO I COULD LAND. CENTER THEN CLRED ME ON A VECTOR TO INTERCEPT THE LOC FOR THE ILS (DME) 10 AT HAYDEN. I BROKE OUT INTO VFR CONDITIONS AS I INTERCEPTED THE LOC. AS I PROCEEDED INBND ON THE LOC I ASSUMED THAT I HAD BEEN CLRED FOR THE APCH TO HAYDEN. AT 15 NM DME ON THE IHDN LOC I STARTED OUT OF 12000' FOR 9000' WHICH IS APPROVED ON THE APCH PLATE. CENTER THEN CAME BACK AFTER RPTING OUT OF 12000' FOR 9000' AND SAID I WAS NOT CLRED FOR AN APCH TO HAYDEN AND TO MAINTAIN 12000' AND HOLD AT THE CHE VOR BECAUSE THE ARPT WAS CLOSED. I WAS ALREADY OUT OF 11000' AND DSNDING FAST. I THEN CANCELLED IFR AND PROCEEDED VFR TO THE HAYDEN ARPT AND CIRCLED THE ARPT WAITING FOR IT TO OPEN. THIS INCIDENT COULD HAVE BEEN PREVENTED IF I HAD VERIFIED CLRNC, LISTENED MORE CLOSELY TO CENTER, AND FOLLOWED ATC INSTRUCTIONS TO THE LETTER AND NOT ASSUMED I WAS CLRED FOR MORE THAN I WAS.

Data retrieved from NASA's ASRS site as of August 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.