Narrative:

I was acting PIC on a newly leased citation one. My co-captain had made one previous trip in the aircraft. We were cleared to taxi out to runway 32 and my copilot ran taxi checklists, and programmed the GPS. We had been experiencing problems with the copilot's radio jack, so he was transmitting over the headset and listening on the speaker. I studied the SID and briefed the copilot and he called chicago tower to advise them we were ready to depart. It was a good VMC day with very gusty winds and fairly light traffic. Runways 27L/right and 32 were in use. I taxied onto the runway whilst the copilot read back the tower's clearance to taxi and remain clear of runway 27R. I was preoccupied with making sure I stayed clear of runway 27R and remained on the correct runway as we were performing an intersection departure, that I only partially copied the tower's instructions. I taxied into position on runway 32 and my copilot told me we were cleared to take off. I asked him 'are you sure? What heading.' he said, 'yes, we're clear to go.' I should have asked him to call tower and clarify, but I didn't. We rolled down runway 32, rotated and climbing through 300 ft, tower called and said that we had not been released and to turn right heading 040 degrees. The copilot replied with the heading change and we continued the climb with a handoff to departure. At cruise altitude, I asked the copilot if he felt that we had been 'cleared for takeoff' and he replied 'yes.' I feel very negligent as PIC of the aircraft that I did not ask for clarification from tower of a takeoff clearance. I realize that we were very fortunate that we did not cause a runway incursion. I have always maintained a good safety record and feel this has been a huge reality check and never again will I ignore my better judgement to question any doubtful decisions. I realize that an accident is caused by a chain of events. Ours were: 1) a rented aircraft with a faulty headset jack, 2) departing from a runway intersection with an unclr tower transmission, 3) failure to verify a takeoff clearance, and 4) failure to communicate effectively as a crew.

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Original NASA ASRS Text

Title: C501 CREW DEPART ORD WITHOUT A TKOF CLRNC AFTER TAXI INTO POS AND HOLD CLRNC.

Narrative: I WAS ACTING PIC ON A NEWLY LEASED CITATION ONE. MY CO-CAPT HAD MADE ONE PREVIOUS TRIP IN THE ACFT. WE WERE CLRED TO TAXI OUT TO RWY 32 AND MY COPLT RAN TAXI CHKLISTS, AND PROGRAMMED THE GPS. WE HAD BEEN EXPERIENCING PROBS WITH THE COPLT'S RADIO JACK, SO HE WAS XMITTING OVER THE HEADSET AND LISTENING ON THE SPEAKER. I STUDIED THE SID AND BRIEFED THE COPLT AND HE CALLED CHICAGO TWR TO ADVISE THEM WE WERE READY TO DEPART. IT WAS A GOOD VMC DAY WITH VERY GUSTY WINDS AND FAIRLY LIGHT TFC. RWYS 27L/R AND 32 WERE IN USE. I TAXIED ONTO THE RWY WHILST THE COPLT READ BACK THE TWR'S CLRNC TO TAXI AND REMAIN CLR OF RWY 27R. I WAS PREOCCUPIED WITH MAKING SURE I STAYED CLR OF RWY 27R AND REMAINED ON THE CORRECT RWY AS WE WERE PERFORMING AN INTXN DEP, THAT I ONLY PARTIALLY COPIED THE TWR'S INSTRUCTIONS. I TAXIED INTO POS ON RWY 32 AND MY COPLT TOLD ME WE WERE CLRED TO TAKE OFF. I ASKED HIM 'ARE YOU SURE? WHAT HEADING.' HE SAID, 'YES, WE'RE CLR TO GO.' I SHOULD HAVE ASKED HIM TO CALL TWR AND CLARIFY, BUT I DIDN'T. WE ROLLED DOWN RWY 32, ROTATED AND CLBING THROUGH 300 FT, TWR CALLED AND SAID THAT WE HAD NOT BEEN RELEASED AND TO TURN R HEADING 040 DEGS. THE COPLT REPLIED WITH THE HEADING CHANGE AND WE CONTINUED THE CLB WITH A HDOF TO DEP. AT CRUISE ALT, I ASKED THE COPLT IF HE FELT THAT WE HAD BEEN 'CLRED FOR TKOF' AND HE REPLIED 'YES.' I FEEL VERY NEGLIGENT AS PIC OF THE ACFT THAT I DID NOT ASK FOR CLARIFICATION FROM TWR OF A TKOF CLRNC. I REALIZE THAT WE WERE VERY FORTUNATE THAT WE DID NOT CAUSE A RWY INCURSION. I HAVE ALWAYS MAINTAINED A GOOD SAFETY RECORD AND FEEL THIS HAS BEEN A HUGE REALITY CHK AND NEVER AGAIN WILL I IGNORE MY BETTER JUDGEMENT TO QUESTION ANY DOUBTFUL DECISIONS. I REALIZE THAT AN ACCIDENT IS CAUSED BY A CHAIN OF EVENTS. OURS WERE: 1) A RENTED ACFT WITH A FAULTY HEADSET JACK, 2) DEPARTING FROM A RWY INTXN WITH AN UNCLR TWR XMISSION, 3) FAILURE TO VERIFY A TKOF CLRNC, AND 4) FAILURE TO COMMUNICATE EFFECTIVELY AS A CREW.

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.