Narrative:

I was at pne, taxi clearance to runway 24. Tower was on with approaching aircraft which refused clearance to land and advised it would hold until runway cleared of potential deer. Tower instructed me to 'hold short runway 24.' I saw other aircraft at what appeared to be 2-3 mi, there was no conflict. Tower advised me of truck on runway looking for deer. I saw truck moving down runway 24. Tower said something about 'cleared.' I understood this to mean 'cleared onto runway,' so I positioned C172 onto runway 24 for departure clearance. I still had holding traffic in sight, the truck was now off the runway. Tower inquired 'where are you,' I responded, 'do you want me on-off runway.' tower advised I had not been 'cleared for takeoff.' I immediately turned to the right from my hold position and moved 30 ft off runway 24 back to taxiway, when tower advised 'no, now you are cleared for takeoff.' so I continued turn 360 degrees back onto runway 24 and departed. There never was a conflict with sole other aircraft, who was then cleared to land after I departed. I apologized to the tower that I made a mistake, that I thought I was cleared onto the runway. The lesson that I learned is that regardless of the words/conversation I have with tower, I will never leave my hold short position until I am 'cleared for takeoff.' this case was a matter of miscom and I admit my error. Upon reflection, I now believe tower's use of the word 'cleared' was in reference to the truck and/or deer activity on runway 24.

Google
 

Original NASA ASRS Text

Title: HOLDING SHORT FOR TKOF, PLT HEARD TWR SAY 'CLRED' AND ASSUMED HE WAS CLRED FOR TKOF. TWR WAS NOT REFERRING TO RPTR. TWR INTERVENED, BUT THEN CLRED HIM FOR TKOF.

Narrative: I WAS AT PNE, TAXI CLRNC TO RWY 24. TWR WAS ON WITH APCHING ACFT WHICH REFUSED CLRNC TO LAND AND ADVISED IT WOULD HOLD UNTIL RWY CLRED OF POTENTIAL DEER. TWR INSTRUCTED ME TO 'HOLD SHORT RWY 24.' I SAW OTHER ACFT AT WHAT APPEARED TO BE 2-3 MI, THERE WAS NO CONFLICT. TWR ADVISED ME OF TRUCK ON RWY LOOKING FOR DEER. I SAW TRUCK MOVING DOWN RWY 24. TWR SAID SOMETHING ABOUT 'CLRED.' I UNDERSTOOD THIS TO MEAN 'CLRED ONTO RWY,' SO I POSITIONED C172 ONTO RWY 24 FOR DEP CLRNC. I STILL HAD HOLDING TFC IN SIGHT, THE TRUCK WAS NOW OFF THE RWY. TWR INQUIRED 'WHERE ARE YOU,' I RESPONDED, 'DO YOU WANT ME ON-OFF RWY.' TWR ADVISED I HAD NOT BEEN 'CLRED FOR TKOF.' I IMMEDIATELY TURNED TO THE R FROM MY HOLD POS AND MOVED 30 FT OFF RWY 24 BACK TO TXWY, WHEN TWR ADVISED 'NO, NOW YOU ARE CLRED FOR TKOF.' SO I CONTINUED TURN 360 DEGS BACK ONTO RWY 24 AND DEPARTED. THERE NEVER WAS A CONFLICT WITH SOLE OTHER ACFT, WHO WAS THEN CLRED TO LAND AFTER I DEPARTED. I APOLOGIZED TO THE TWR THAT I MADE A MISTAKE, THAT I THOUGHT I WAS CLRED ONTO THE RWY. THE LESSON THAT I LEARNED IS THAT REGARDLESS OF THE WORDS/CONVERSATION I HAVE WITH TWR, I WILL NEVER LEAVE MY HOLD SHORT POS UNTIL I AM 'CLRED FOR TKOF.' THIS CASE WAS A MATTER OF MISCOM AND I ADMIT MY ERROR. UPON REFLECTION, I NOW BELIEVE TWR'S USE OF THE WORD 'CLRED' WAS IN REF TO THE TRUCK AND/OR DEER ACTIVITY ON RWY 24.

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.