Narrative:

After start-up; I listened to ATIS which indicated the active runway (27). I contacted ground and was directed to proceed to runway 27. After run-up I pulled up to hold short line; and called tower announcing I was ready to take off; giving runway number (27) and direction. As soon as I un-keyed I heard 'cleared for takeoff' with no further transmission. I visually cleared the approach path and replied with my call sign and repeated 'cleared for takeoff.' I then taxied onto the runway and got into takeoff position; but did not start rolling. Tower then called and told me to hold short where I was as there was an aircraft departing on a crossing runway (36). The threshold area of this runway was not visible to me. Obviously; I had accepted the clearance for the aircraft departing on runway 36. So I never was cleared onto runway 27. Had the local tower controller not been observant and noticed I had pulled onto the runway this could have been much worse. In hindsight I should have never accepted a clearance where I did not hear my call sign; and the runway number for takeoff. Also; the speed with which the controller replied to my announcement that I was ready for takeoff was very quick; which was a hint that something was not right; I should have been more wary.

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Original NASA ASRS Text

Title: M20 PLT TOOK A TKOF CLRNC FOR ANOTHER ACFT ON A XING RWY AND TAXIED INTO POS. THE LCL CTLR OBSERVED THE ERROR AND HELD THE M20 IN POS.

Narrative: AFTER START-UP; I LISTENED TO ATIS WHICH INDICATED THE ACTIVE RWY (27). I CONTACTED GND AND WAS DIRECTED TO PROCEED TO RWY 27. AFTER RUN-UP I PULLED UP TO HOLD SHORT LINE; AND CALLED TWR ANNOUNCING I WAS READY TO TAKE OFF; GIVING RWY NUMBER (27) AND DIRECTION. AS SOON AS I UN-KEYED I HEARD 'CLRED FOR TKOF' WITH NO FURTHER XMISSION. I VISUALLY CLRED THE APCH PATH AND REPLIED WITH MY CALL SIGN AND REPEATED 'CLRED FOR TKOF.' I THEN TAXIED ONTO THE RWY AND GOT INTO TKOF POS; BUT DID NOT START ROLLING. TWR THEN CALLED AND TOLD ME TO HOLD SHORT WHERE I WAS AS THERE WAS AN ACFT DEPARTING ON A XING RWY (36). THE THRESHOLD AREA OF THIS RWY WAS NOT VISIBLE TO ME. OBVIOUSLY; I HAD ACCEPTED THE CLRNC FOR THE ACFT DEPARTING ON RWY 36. SO I NEVER WAS CLRED ONTO RWY 27. HAD THE LCL TWR CTLR NOT BEEN OBSERVANT AND NOTICED I HAD PULLED ONTO THE RWY THIS COULD HAVE BEEN MUCH WORSE. IN HINDSIGHT I SHOULD HAVE NEVER ACCEPTED A CLRNC WHERE I DID NOT HEAR MY CALL SIGN; AND THE RWY NUMBER FOR TKOF. ALSO; THE SPD WITH WHICH THE CTLR REPLIED TO MY ANNOUNCEMENT THAT I WAS READY FOR TKOF WAS VERY QUICK; WHICH WAS A HINT THAT SOMETHING WAS NOT RIGHT; I SHOULD HAVE BEEN MORE WARY.

Data retrieved from NASA's ASRS site as of January 2009 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.