Narrative:

I called tower and requested VFR takeoff in sequence. Tower called and asked for departure request. I responded right crosswind. Tower cleared me into position and hold. An small aircraft had been cleared to takeoff just prior to tower clearing me into position and hold. Upon holding for a few seconds tower said I was approved or cleared for crosswind departure at bridge. I asked tower what small aircraft ahead was going to do with no response. I applied takeoff power and when 30-40 mph tower said, 'cleared for takeoff.' upon initial climb (100-200' MSL) a different controller called to inform me not to takeoff west/O a clearance. Upon return 3 hours later I met with tower supervisor who played tapes and told me person who was handling traffic was training and he understood how instruction could be construed as clearance. Callback conversation with reporter revealed the following: tower supervisor stated he did not intend to press the issue since the trnee's approval for the crosswind departure at the bridge may have been misleading. Reporter knows that he did not specifically get clearance for takeoff until he had started to roll, and that until he hears the phrase 'cleared for takeoff,' he should not move.

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Original NASA ASRS Text

Title: SMT TOOK TWR APPROVAL OF CROSSWIND DEP REQUEST AS TKOF CLRNC AND STARTED TKOF WITHOUT PROPER CLRNC.

Narrative: I CALLED TWR AND REQUESTED VFR TKOF IN SEQUENCE. TWR CALLED AND ASKED FOR DEP REQUEST. I RESPONDED RIGHT XWIND. TWR CLRED ME INTO POS AND HOLD. AN SMA HAD BEEN CLRED TO TKOF JUST PRIOR TO TWR CLRING ME INTO POS AND HOLD. UPON HOLDING FOR A FEW SECS TWR SAID I WAS APPROVED OR CLRED FOR XWIND DEP AT BRIDGE. I ASKED TWR WHAT SMA AHEAD WAS GOING TO DO WITH NO RESPONSE. I APPLIED TKOF PWR AND WHEN 30-40 MPH TWR SAID, 'CLRED FOR TKOF.' UPON INITIAL CLB (100-200' MSL) A DIFFERENT CTLR CALLED TO INFORM ME NOT TO TKOF W/O A CLRNC. UPON RETURN 3 HRS LATER I MET WITH TWR SUPVR WHO PLAYED TAPES AND TOLD ME PERSON WHO WAS HANDLING TFC WAS TRNING AND HE UNDERSTOOD HOW INSTRUCTION COULD BE CONSTRUED AS CLRNC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: TWR SUPVR STATED HE DID NOT INTEND TO PRESS THE ISSUE SINCE THE TRNEE'S APPROVAL FOR THE XWIND DEP AT THE BRIDGE MAY HAVE BEEN MISLEADING. RPTR KNOWS THAT HE DID NOT SPECIFICALLY GET CLRNC FOR TKOF UNTIL HE HAD STARTED TO ROLL, AND THAT UNTIL HE HEARS THE PHRASE 'CLRED FOR TKOF,' HE SHOULD NOT MOVE.

Data retrieved from NASA's ASRS site as of August 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.