Narrative:

The incident aircraft was prepared for the first in a series of flts. The first leg was to cny, utah, with an XA00 takeoff. After an extensive preflight including weight and balance, performance data, WX considerations, and a face to face WX brief, the flight was boarded by 2 passenger, and began taxi to the active runway. The flts clearance and FMS loading had already taken place on the ramp at FBO via a power cart. The departure runway was 9L at oak. The aircraft taxied without incident, and just prior to the hold short line, the crew both believed that a takeoff clearance was issued and began the takeoff maneuver. Shortly after takeoff, the tower controller called us and informed the crew that he had not issued a takeoff clearance, only a hold short command. A few mins later after the flight was stable in a cruise condition, the PIC requested that the sic call the oak tower for further information. Mr X answered the call at the oak tower and asked what had occurred. The sic explained that a hold short clearance was not understood by the crew and stated that perhaps some distraction had caused 2 pilots to miss this very important instruction. Mr X conducted some in-flight training with us and asked the crew on landing to review takeoff clearance procedures, and that the matter would end at this point.

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Original NASA ASRS Text

Title: RWY INCURSION ASSOCIATED WITH AN UNAUTH RWY ENTRY AND TKOF BY A CORPORATE.

Narrative: THE INCIDENT ACFT WAS PREPARED FOR THE FIRST IN A SERIES OF FLTS. THE FIRST LEG WAS TO CNY, UTAH, WITH AN XA00 TKOF. AFTER AN EXTENSIVE PREFLT INCLUDING WT AND BAL, PERFORMANCE DATA, WX CONSIDERATIONS, AND A FACE TO FACE WX BRIEF, THE FLT WAS BOARDED BY 2 PAX, AND BEGAN TAXI TO THE ACTIVE RWY. THE FLTS CLRNC AND FMS LOADING HAD ALREADY TAKEN PLACE ON THE RAMP AT FBO VIA A PWR CART. THE DEP RWY WAS 9L AT OAK. THE ACFT TAXIED WITHOUT INCIDENT, AND JUST PRIOR TO THE HOLD SHORT LINE, THE CREW BOTH BELIEVED THAT A TKOF CLRNC WAS ISSUED AND BEGAN THE TKOF MANEUVER. SHORTLY AFTER TKOF, THE TWR CTLR CALLED US AND INFORMED THE CREW THAT HE HAD NOT ISSUED A TKOF CLRNC, ONLY A HOLD SHORT COMMAND. A FEW MINS LATER AFTER THE FLT WAS STABLE IN A CRUISE CONDITION, THE PIC REQUESTED THAT THE SIC CALL THE OAK TWR FOR FURTHER INFO. MR X ANSWERED THE CALL AT THE OAK TWR AND ASKED WHAT HAD OCCURRED. THE SIC EXPLAINED THAT A HOLD SHORT CLRNC WAS NOT UNDERSTOOD BY THE CREW AND STATED THAT PERHAPS SOME DISTR HAD CAUSED 2 PLTS TO MISS THIS VERY IMPORTANT INSTRUCTION. MR X CONDUCTED SOME INFLT TRAINING WITH US AND ASKED THE CREW ON LNDG TO REVIEW TKOF CLRNC PROCS, AND THAT THE MATTER WOULD END AT THIS POINT.

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.