Narrative:

On taxi-out, normal procedures in effect. As we neared the runway, the controller issued instructions to either taxi into position and hold 'or cleared for takeoff.' I didn't remember which because I was responding to the checklist at the time, but I did note that I did not have to stop the aircraft as we rolled onto the runway, I questioned the first officer 'cleared for takeoff?' he said 'yes' and looked at me and nodded his head. Since I had not remembered, I was aware that I was totally depending on him. I again asked 'you're sure?' he said 'yes.' so away we went into VFR conditions. At about 300 ft AGL the tower controller said 'cleared for takeoff, contact departure.' that was such an unusual directive that I called back to the tower on another frequency to inquire about the incident. I was informed that we had taken off without clearance! I believe that the mistake made by me was the old proverbial one, verify if not sure! I wasn't sure but the other pilot was pretty insistent. In his defense he is very new to the aircraft and procedures (first trip after training completed) and min time of training, resulting in heavy workload (checklist, performance, communications) all at the same time. Result -- overload! It was my first trip in 33 days, so I was a little slow myself. Lesson learned -- if not positive -- verify. For your own personal peace of mind! Thanks and hope this contributes something! Callback conversation with reporter revealed the following information. Reporter participated in structured callback for runway incursion survey. Reporter gave more information reference aircraft equipment and WX. Says ATC had min involvement in incident but wishes that controllers understood better the advantages of keeping aircraft in continuous motion rather than stop and go movements on the ground. Says that he and first officer both heard the controller give a clearance, but apparently neither of them heard it correctly. When PIC asked the question 'cleared for takeoff,' the first officer may have interpreted that as a statement of fact. This was third day of a four day schedule and they had been on duty for about 9 hours that day. No conflict with any other traffic. There was a previous landing, but that aircraft had already turned off the runway.

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Original NASA ASRS Text

Title: ACR TKOF WITHOUT CLRNC.

Narrative: ON TAXI-OUT, NORMAL PROCS IN EFFECT. AS WE NEARED THE RWY, THE CTLR ISSUED INSTRUCTIONS TO EITHER TAXI INTO POS AND HOLD 'OR CLRED FOR TKOF.' I DIDN'T REMEMBER WHICH BECAUSE I WAS RESPONDING TO THE CHKLIST AT THE TIME, BUT I DID NOTE THAT I DID NOT HAVE TO STOP THE ACFT AS WE ROLLED ONTO THE RWY, I QUESTIONED THE FO 'CLRED FOR TKOF?' HE SAID 'YES' AND LOOKED AT ME AND NODDED HIS HEAD. SINCE I HAD NOT REMEMBERED, I WAS AWARE THAT I WAS TOTALLY DEPENDING ON HIM. I AGAIN ASKED 'YOU'RE SURE?' HE SAID 'YES.' SO AWAY WE WENT INTO VFR CONDITIONS. AT ABOUT 300 FT AGL THE TWR CTLR SAID 'CLRED FOR TKOF, CONTACT DEP.' THAT WAS SUCH AN UNUSUAL DIRECTIVE THAT I CALLED BACK TO THE TWR ON ANOTHER FREQ TO INQUIRE ABOUT THE INCIDENT. I WAS INFORMED THAT WE HAD TAKEN OFF WITHOUT CLRNC! I BELIEVE THAT THE MISTAKE MADE BY ME WAS THE OLD PROVERBIAL ONE, VERIFY IF NOT SURE! I WASN'T SURE BUT THE OTHER PLT WAS PRETTY INSISTENT. IN HIS DEFENSE HE IS VERY NEW TO THE ACFT AND PROCS (FIRST TRIP AFTER TRAINING COMPLETED) AND MIN TIME OF TRAINING, RESULTING IN HVY WORKLOAD (CHKLIST, PERFORMANCE, COMS) ALL AT THE SAME TIME. RESULT -- OVERLOAD! IT WAS MY FIRST TRIP IN 33 DAYS, SO I WAS A LITTLE SLOW MYSELF. LESSON LEARNED -- IF NOT POSITIVE -- VERIFY. FOR YOUR OWN PERSONAL PEACE OF MIND! THANKS AND HOPE THIS CONTRIBUTES SOMETHING! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR PARTICIPATED IN STRUCTURED CALLBACK FOR RWY INCURSION SURVEY. RPTR GAVE MORE INFO REF ACFT EQUIP AND WX. SAYS ATC HAD MIN INVOLVEMENT IN INCIDENT BUT WISHES THAT CTLRS UNDERSTOOD BETTER THE ADVANTAGES OF KEEPING ACFT IN CONTINUOUS MOTION RATHER THAN STOP AND GO MOVEMENTS ON THE GND. SAYS THAT HE AND FO BOTH HEARD THE CTLR GIVE A CLRNC, BUT APPARENTLY NEITHER OF THEM HEARD IT CORRECTLY. WHEN PIC ASKED THE QUESTION 'CLRED FOR TKOF,' THE FO MAY HAVE INTERPRETED THAT AS A STATEMENT OF FACT. THIS WAS THIRD DAY OF A FOUR DAY SCHEDULE AND THEY HAD BEEN ON DUTY FOR ABOUT 9 HRS THAT DAY. NO CONFLICT WITH ANY OTHER TFC. THERE WAS A PREVIOUS LNDG, BUT THAT ACFT HAD ALREADY TURNED OFF THE RWY.

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.