Narrative:

At approximately midnight (CST), I departed hsv. I had made the trip to hsv a few hours earlier to visit some friends of min who work for an airline there. They made some comments about the closure of the control tower. They informed me the controllers there habitually close the tower after the arrival of the last schedule air carrier. I asked a gentleman behind the counter if the tower had already closed. He looked at a wall clock and affirmed that the tower was not in operation. Since we had assumed from the information given by these sources that the tower was closed, we broadcast (or thought we broadcast) our intentions over the CTAF. Since we were led to believe that nobody was at the tower, an attempt to receive ATIS information seemed futile. We continued to announce our position on the field and our intentions. We were not surprised, due to the late hour and the absence of other traffic, when nobody responded to our xmissions. We did not see (and to the best of my knowledge were not given) any light gun signals from the tower. 28 mi north of bhm ATIS advised that conditions were better than 5000' ceiling and 5 mi visibility, and that the wind was calm. The controller asked us to call the tower via phone upon landing. I complied and he informed me that we had departed from a controled field using improper communications procedures. He said that the hsv controller (the control tower was still operational) had tried to contact us but was unable. I still do not know why the tower was unable to contact us during our departure, nor do I know why the hsv controller did not hear our xmissions. Could we have inadvertently dialed in an incorrect numeral while selecting the frequency in our communications radio? We experienced no other radio/communications problems during that flight.

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Original NASA ASRS Text

Title: GA SMA UNAUTH TAXI TKOF FROM AN ARPT WITH PART-TIME ATCT.

Narrative: AT APPROX MIDNIGHT (CST), I DEPARTED HSV. I HAD MADE THE TRIP TO HSV A FEW HRS EARLIER TO VISIT SOME FRIENDS OF MIN WHO WORK FOR AN AIRLINE THERE. THEY MADE SOME COMMENTS ABOUT THE CLOSURE OF THE CTL TWR. THEY INFORMED ME THE CTLRS THERE HABITUALLY CLOSE THE TWR AFTER THE ARR OF THE LAST SCHEDULE ACR. I ASKED A GENTLEMAN BEHIND THE COUNTER IF THE TWR HAD ALREADY CLOSED. HE LOOKED AT A WALL CLOCK AND AFFIRMED THAT THE TWR WAS NOT IN OPERATION. SINCE WE HAD ASSUMED FROM THE INFO GIVEN BY THESE SOURCES THAT THE TWR WAS CLOSED, WE BROADCAST (OR THOUGHT WE BROADCAST) OUR INTENTIONS OVER THE CTAF. SINCE WE WERE LED TO BELIEVE THAT NOBODY WAS AT THE TWR, AN ATTEMPT TO RECEIVE ATIS INFO SEEMED FUTILE. WE CONTINUED TO ANNOUNCE OUR POS ON THE FIELD AND OUR INTENTIONS. WE WERE NOT SURPRISED, DUE TO THE LATE HR AND THE ABSENCE OF OTHER TFC, WHEN NOBODY RESPONDED TO OUR XMISSIONS. WE DID NOT SEE (AND TO THE BEST OF MY KNOWLEDGE WERE NOT GIVEN) ANY LIGHT GUN SIGNALS FROM THE TWR. 28 MI N OF BHM ATIS ADVISED THAT CONDITIONS WERE BETTER THAN 5000' CEILING AND 5 MI VISIBILITY, AND THAT THE WIND WAS CALM. THE CTLR ASKED US TO CALL THE TWR VIA PHONE UPON LNDG. I COMPLIED AND HE INFORMED ME THAT WE HAD DEPARTED FROM A CTLED FIELD USING IMPROPER COMS PROCS. HE SAID THAT THE HSV CTLR (THE CTL TWR WAS STILL OPERATIONAL) HAD TRIED TO CONTACT US BUT WAS UNABLE. I STILL DO NOT KNOW WHY THE TWR WAS UNABLE TO CONTACT US DURING OUR DEP, NOR DO I KNOW WHY THE HSV CTLR DID NOT HEAR OUR XMISSIONS. COULD WE HAVE INADVERTENTLY DIALED IN AN INCORRECT NUMERAL WHILE SELECTING THE FREQ IN OUR COMS RADIO? WE EXPERIENCED NO OTHER RADIO/COMS PROBS DURING THAT FLT.

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.