Narrative:

After we received ATIS and a clearance; we taxied to and held short of runway 30L for a full length departure at iwa. There were several aircraft in the pattern; and the radio frequencys were busy; but there were no other aircraft in the pattern; and there were no other aircraft that we heard or could see holding short of runway 30L. We waited about 1 min and received what we thought was an immediate takeoff clearance for runway 30L; with a cherokee on short final. I acknowledged the clearance. There were no other aircraft in the area; and we completed our takeoff checklist and began our takeoff roll. As we lined up on the centerline of the runway; we saw a single engine; piston aircraft taking off downfield on our runway. The first officer and I both applied brakes as he retarded the thrust levers. At that time; the tower told us to hold our position and called a go around for the cherokee. The controller told us that our last instruction was to hold short. I informed him that we had; then entered the runway after receiving our immediate takeoff instruction. He told us that it had been for a cirrus making an intersection departure. We could not see the aircraft at the intersection and did not know he was there. The controller was unclear enough to make us think that he called us instead of the cirrus. Apparently my transmission acknowledging our takeoff clearance had been blocked by the cirrus; and the tower did not notice us taking the active runway until we were lined up and moving down the runway. Supplemental information from acn 701224: the flight crew allowed themselves to feel hurried by the 'immediate' takeoff clearance. There was no doubt in my mind that the takeoff clearance was for us as the captain read it back. We had been ready at the end for some time; and we were the first aircraft in sequence at the end of the runway. The lack of any correction from the tower after the readback made me absolutely confident we were cleared to take the runway and depart.

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Original NASA ASRS Text

Title: LEAR-25 FLT CREW HAS A RWY INCURSION AT IWA.

Narrative: AFTER WE RECEIVED ATIS AND A CLRNC; WE TAXIED TO AND HELD SHORT OF RWY 30L FOR A FULL LENGTH DEP AT IWA. THERE WERE SEVERAL ACFT IN THE PATTERN; AND THE RADIO FREQS WERE BUSY; BUT THERE WERE NO OTHER ACFT IN THE PATTERN; AND THERE WERE NO OTHER ACFT THAT WE HEARD OR COULD SEE HOLDING SHORT OF RWY 30L. WE WAITED ABOUT 1 MIN AND RECEIVED WHAT WE THOUGHT WAS AN IMMEDIATE TKOF CLRNC FOR RWY 30L; WITH A CHEROKEE ON SHORT FINAL. I ACKNOWLEDGED THE CLRNC. THERE WERE NO OTHER ACFT IN THE AREA; AND WE COMPLETED OUR TKOF CHKLIST AND BEGAN OUR TKOF ROLL. AS WE LINED UP ON THE CTRLINE OF THE RWY; WE SAW A SINGLE ENG; PISTON ACFT TAKING OFF DOWNFIELD ON OUR RWY. THE FO AND I BOTH APPLIED BRAKES AS HE RETARDED THE THRUST LEVERS. AT THAT TIME; THE TWR TOLD US TO HOLD OUR POS AND CALLED A GAR FOR THE CHEROKEE. THE CTLR TOLD US THAT OUR LAST INSTRUCTION WAS TO HOLD SHORT. I INFORMED HIM THAT WE HAD; THEN ENTERED THE RWY AFTER RECEIVING OUR IMMEDIATE TKOF INSTRUCTION. HE TOLD US THAT IT HAD BEEN FOR A CIRRUS MAKING AN INTXN DEP. WE COULD NOT SEE THE ACFT AT THE INTXN AND DID NOT KNOW HE WAS THERE. THE CTLR WAS UNCLEAR ENOUGH TO MAKE US THINK THAT HE CALLED US INSTEAD OF THE CIRRUS. APPARENTLY MY XMISSION ACKNOWLEDGING OUR TKOF CLRNC HAD BEEN BLOCKED BY THE CIRRUS; AND THE TWR DID NOT NOTICE US TAKING THE ACTIVE RWY UNTIL WE WERE LINED UP AND MOVING DOWN THE RWY. SUPPLEMENTAL INFO FROM ACN 701224: THE FLT CREW ALLOWED THEMSELVES TO FEEL HURRIED BY THE 'IMMEDIATE' TKOF CLRNC. THERE WAS NO DOUBT IN MY MIND THAT THE TKOF CLRNC WAS FOR US AS THE CAPT READ IT BACK. WE HAD BEEN READY AT THE END FOR SOME TIME; AND WE WERE THE FIRST ACFT IN SEQUENCE AT THE END OF THE RWY. THE LACK OF ANY CORRECTION FROM THE TWR AFTER THE READBACK MADE ME ABSOLUTELY CONFIDENT WE WERE CLRED TO TAKE THE RWY AND DEPART.

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.