AN SMA PLT TOOK OFF WITH HIS RADIO VOLUME TURNED DOWN. THE TWR MAY HAVE NOT YET BEEN OPEN.

Narrative

IT WAS EARLY MORNING AND DARK OUTSIDE. BEING READY FOR TAXI; I LISTENED FOR ATIS BUT DIDN'T RECEIVE AND THEN CALLED TWR FOR TAXI BUT DIDN'T GET A RESPONSE. I THEN CHKED MY FLT GUIDE FOR TWR OP HRS AND CONFIRMED TO OPENED AT XA00. MY WATCH IS NOT ALWAYS ACCURATE AND I WAS SHOWING A FEW MINS AFTER XA00 AND SO ASSUMED TWR WAS NOT OPEN AND SO TAXIED TO AN INTXN OF RWY 11. BEFORE TKOF; I BROADCAST OVER TWR FREQ THAT I WAS DEPARTING 11 NE AND THEN PROCEEDED TO TKOF. UPON REACHING ASPEN; I RADIOED APCH AND AGAIN GOT NO RESPONSE. BY THIS TIME IT WAS LIGHT AND UPON MAKING A CHK I DISCOVERED THE VOLUME ON MY RADIO WAS TURNED DOWN. I ASSUME NOW THAT THIS IS THE REASON I DIDN'T RECEIVE IN GRAND JUNCTION. ALTHOUGH I HAVE NOT CONFIRMED THIS; I NOW BELIEVE THAT TWR PROBABLY WAS OPEN AND HEARD MY BROADCASTS. IF THIS IS TRUE; MY MISTAKE WAS TO ASSUME TWR WAS NOT OPEN AND TO TAXI AND TKOF. CONTRIBUTING TO THIS INCIDENT IS THE FACT THAT ONLY 2 PLTS FLY THIS AIRPLANE AND THE RADIOS ARE ON A MASTER SWITCH. NORMAL PROCS ARE TO TURN ON THE MASTER AND THE RADIO VOLUMES ARE PRESET. IN THIS INCIDENT; THE PREVIOUS PLT HAD FOR SOME REASON TURNED THE VOLUME DOWN. AT XA00 IT WAS DARK; AND WHEN I TURNED ON THE MASTER; EVERYTHING CAME ON AS NORMAL AND IT DID NOT OCCUR TO ME TO CHK THE VOLUME -- IT WAS SO CLOSE TO XA00 IT WAS MY ASSUMPTION TWR WAS NOT OPEN YET. AND FOR THAT MATTER THIS STILL COULD BE THE CASE.