Narrative:

Cleared to taxi to runway 33 at bur, ground instructed us to contact tower on 118.7, we did so. I was in the middle of the before takeoff check, so the captain was on the radio. Tower said 'xx you up?' captain said 'affirmative.' tower said 'xx cleared for takeoff runway 33'. Captain said 'we'll need about a minute more'. Tower said 'roger'. I completed checklist to the point of captain's briefing. While the captain was in the middle of the briefing, tower said 'xx change your departure frequency to XXXX'. I read back the new frequency and said we would be ready in just a minute. Captain finished the brief and we taxied out onto the runway, applied power and departed. Out of 1500' tower said 'xx you were instructed to hold short of 33'. Captain said 'did we acknowledge that?' tower said 'I instructed you to hold short when I gave you the new departure frequency, did you hear me clear you for takeoff a second time?' captain said 'we never received or acknowledged your hold short, sorry'. Tower said 'no problem, contact departure, good day'. Several factors enter into this occurrence. It was early morning. We were in no hurry to depart and the airport was not busy. Ground control told us to contact tower prior to our reaching the runway. Tower cleared us for takeoff before we requested it. We were busy doing our checklist and briefing, which may have caused a distraction. I believe I may have blocked the amended clearance by reading back the new frequency before the controller finished his transmission, since there was a delay in departure from the time the original clearance was issued. I believe that we should have confirmed cleared for takeoff before taking the runway, however, it was quiet on the frequency and this may have caused us to feel we were still cleared to go. We did not read back hold short and tower did not catch it.

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Original NASA ASRS Text

Title: TKOF WITHOUT ATC CLRNC.

Narrative: CLRED TO TAXI TO RWY 33 AT BUR, GND INSTRUCTED US TO CONTACT TWR ON 118.7, WE DID SO. I WAS IN THE MIDDLE OF THE BEFORE TKOF CHECK, SO THE CAPT WAS ON THE RADIO. TWR SAID 'XX YOU UP?' CAPT SAID 'AFFIRMATIVE.' TWR SAID 'XX CLRED FOR TKOF RWY 33'. CAPT SAID 'WE'LL NEED ABOUT A MINUTE MORE'. TWR SAID 'ROGER'. I COMPLETED CHECKLIST TO THE POINT OF CAPT'S BRIEFING. WHILE THE CAPT WAS IN THE MIDDLE OF THE BRIEFING, TWR SAID 'XX CHANGE YOUR DEP FREQ TO XXXX'. I READ BACK THE NEW FREQ AND SAID WE WOULD BE READY IN JUST A MINUTE. CAPT FINISHED THE BRIEF AND WE TAXIED OUT ONTO THE RWY, APPLIED POWER AND DEPARTED. OUT OF 1500' TWR SAID 'XX YOU WERE INSTRUCTED TO HOLD SHORT OF 33'. CAPT SAID 'DID WE ACKNOWLEDGE THAT?' TWR SAID 'I INSTRUCTED YOU TO HOLD SHORT WHEN I GAVE YOU THE NEW DEP FREQ, DID YOU HEAR ME CLEAR YOU FOR TKOF A SECOND TIME?' CAPT SAID 'WE NEVER RECEIVED OR ACKNOWLEDGED YOUR HOLD SHORT, SORRY'. TWR SAID 'NO PROBLEM, CONTACT DEP, GOOD DAY'. SEVERAL FACTORS ENTER INTO THIS OCCURRENCE. IT WAS EARLY MORNING. WE WERE IN NO HURRY TO DEPART AND THE ARPT WAS NOT BUSY. GND CTL TOLD US TO CONTACT TWR PRIOR TO OUR REACHING THE RWY. TWR CLRED US FOR TKOF BEFORE WE REQUESTED IT. WE WERE BUSY DOING OUR CHECKLIST AND BRIEFING, WHICH MAY HAVE CAUSED A DISTR. I BELIEVE I MAY HAVE BLOCKED THE AMENDED CLRNC BY READING BACK THE NEW FREQ BEFORE THE CTLR FINISHED HIS XMISSION, SINCE THERE WAS A DELAY IN DEP FROM THE TIME THE ORIGINAL CLRNC WAS ISSUED. I BELIEVE THAT WE SHOULD HAVE CONFIRMED CLRED FOR TKOF BEFORE TAKING THE RWY, HOWEVER, IT WAS QUIET ON THE FREQ AND THIS MAY HAVE CAUSED US TO FEEL WE WERE STILL CLRED TO GO. WE DID NOT READ BACK HOLD SHORT AND TWR DID NOT CATCH IT.

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.