Narrative:

Prior to startup for departure, I contacted clearance delivery for departure instructions and a squawk code, then contacted ground. I was cleared to taxi to runway 3 via taxiway B. Ground instructed me to follow the taxiway out of GA parking, and turn right at taxiway B, which I did. I was unable to see a separate runup area, so upon reaching runway 3, I stopped behind the runway boundary, switched to tower frequency, and began my runup. Tower called and asked if I was on frequency. I said I was, and was told that I was blocking the taxiway. I offered to inch forward and to the side so that the aircraft behind me could cross the runway, and tower told me that I should move to the runup area. I turned the aircraft around, pointing it now at the side of the taxiway away from the runway and asked if the direction I was now pointing was the direction of the runup area (it was a wide taxiway, and I thought the far side might be the runup area). Tower told me 'no, just go to the end of runway 3.' I thought it was an unusual place for a runup, but I visually confirmed that there were no aircraft on final for runway 3, and the tower frequency was congested, so I simply responded 'end of runway 3.' as soon as I was on the runway, tower called and asked if I had entered the runway -- evidently surprised that I had. I responded that I thought that's what he had told me to do. He responded that he hadn't, but never mind, I was cleared to position and hold runway 3. My passenger confirmed that she had heard tower tell me to 'go to the end of runway 3.' in discussion afterwards, we concluded that the controller had meant that we should have gone to the extreme southern edge of the taxiway adjacent to the end of runway 3. The situation could have been avoided if: 1) I had asked ground about the specific location of the runup area. 2) tower had indicated 'the taxiway adjacent to the end of runway 3' instead of 'the end of runway 3.' 3) I had called for confirmation on what I thought was an unusual instruction.

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Original NASA ASRS Text

Title: C172 PLT CONFUSES INSTRUCTIONS AND TAXIES ONTO RWY FOR RUNUP.

Narrative: PRIOR TO STARTUP FOR DEP, I CONTACTED CLRNC DELIVERY FOR DEP INSTRUCTIONS AND A SQUAWK CODE, THEN CONTACTED GND. I WAS CLRED TO TAXI TO RWY 3 VIA TXWY B. GND INSTRUCTED ME TO FOLLOW THE TXWY OUT OF GA PARKING, AND TURN R AT TXWY B, WHICH I DID. I WAS UNABLE TO SEE A SEPARATE RUNUP AREA, SO UPON REACHING RWY 3, I STOPPED BEHIND THE RWY BOUNDARY, SWITCHED TO TWR FREQ, AND BEGAN MY RUNUP. TWR CALLED AND ASKED IF I WAS ON FREQ. I SAID I WAS, AND WAS TOLD THAT I WAS BLOCKING THE TXWY. I OFFERED TO INCH FORWARD AND TO THE SIDE SO THAT THE ACFT BEHIND ME COULD CROSS THE RWY, AND TWR TOLD ME THAT I SHOULD MOVE TO THE RUNUP AREA. I TURNED THE ACFT AROUND, POINTING IT NOW AT THE SIDE OF THE TXWY AWAY FROM THE RWY AND ASKED IF THE DIRECTION I WAS NOW POINTING WAS THE DIRECTION OF THE RUNUP AREA (IT WAS A WIDE TXWY, AND I THOUGHT THE FAR SIDE MIGHT BE THE RUNUP AREA). TWR TOLD ME 'NO, JUST GO TO THE END OF RWY 3.' I THOUGHT IT WAS AN UNUSUAL PLACE FOR A RUNUP, BUT I VISUALLY CONFIRMED THAT THERE WERE NO ACFT ON FINAL FOR RWY 3, AND THE TWR FREQ WAS CONGESTED, SO I SIMPLY RESPONDED 'END OF RWY 3.' AS SOON AS I WAS ON THE RWY, TWR CALLED AND ASKED IF I HAD ENTERED THE RWY -- EVIDENTLY SURPRISED THAT I HAD. I RESPONDED THAT I THOUGHT THAT'S WHAT HE HAD TOLD ME TO DO. HE RESPONDED THAT HE HADN'T, BUT NEVER MIND, I WAS CLRED TO POS AND HOLD RWY 3. MY PAX CONFIRMED THAT SHE HAD HEARD TWR TELL ME TO 'GO TO THE END OF RWY 3.' IN DISCUSSION AFTERWARDS, WE CONCLUDED THAT THE CTLR HAD MEANT THAT WE SHOULD HAVE GONE TO THE EXTREME SOUTHERN EDGE OF THE TXWY ADJACENT TO THE END OF RWY 3. THE SIT COULD HAVE BEEN AVOIDED IF: 1) I HAD ASKED GND ABOUT THE SPECIFIC LOCATION OF THE RUNUP AREA. 2) TWR HAD INDICATED 'THE TXWY ADJACENT TO THE END OF RWY 3' INSTEAD OF 'THE END OF RWY 3.' 3) I HAD CALLED FOR CONFIRMATION ON WHAT I THOUGHT WAS AN UNUSUAL INSTRUCTION.

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.