Narrative:

PF (captain-myself) was cleared for position and hold; but was predetermined that airport would be closed. I forgot that fact; tower advised runway conditions; copilot (PNF) advised receipt and said we were rolling. I released brakes; added power and took off. Tower advised negative; abort takeoff; no IFR release. Too late to abort on snow/ice covered runway. Tower advised to remain VFR and enter right downwind for runway. At that point; tower gave us IFR release to fly direct to destination. Cause of pilot deviation error: (takeoff without clearance) was that I had planned on departing prior to tower opening. However; during taxi for takeoff; tower announced it was now opening as class D airspace and then issued our clearance as filed. This flight being a 'lifeguard' medical flight transporting long patient to clinic; time was critical and I got focused on takeoff with proper tower takeoff clearance. Afterwards; crew briefed and I instructed copilot to be more assertive and be aggressive and tell me 'hold in position' until we get clearance for takeoff! In summary: when a pilot is cleared for 'taxi into position and hold;' he's cocked like a 45 caliber revolver ready to release with the tower's next words. When tower said runway conditions; and copilot responded; I automatically released brakes; added power and 'rolled;' just like always. I was fixed on the takeoff and predetermined to go with the next transmission from tower!

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Original NASA ASRS Text

Title: A LIFEGUARD MEDICAL FLT INITIATED AN IFR TKOF WITHOUT TWR CLRNC SHORTLY AFTER THE CLOSED TWR OPENED.

Narrative: PF (CAPT-MYSELF) WAS CLRED FOR POS AND HOLD; BUT WAS PREDETERMINED THAT ARPT WOULD BE CLOSED. I FORGOT THAT FACT; TWR ADVISED RWY CONDITIONS; COPLT (PNF) ADVISED RECEIPT AND SAID WE WERE ROLLING. I RELEASED BRAKES; ADDED PWR AND TOOK OFF. TWR ADVISED NEGATIVE; ABORT TKOF; NO IFR RELEASE. TOO LATE TO ABORT ON SNOW/ICE COVERED RWY. TWR ADVISED TO REMAIN VFR AND ENTER R DOWNWIND FOR RWY. AT THAT POINT; TWR GAVE US IFR RELEASE TO FLY DIRECT TO DEST. CAUSE OF PLTDEV ERROR: (TKOF WITHOUT CLRNC) WAS THAT I HAD PLANNED ON DEPARTING PRIOR TO TWR OPENING. HOWEVER; DURING TAXI FOR TKOF; TWR ANNOUNCED IT WAS NOW OPENING AS CLASS D AIRSPACE AND THEN ISSUED OUR CLRNC AS FILED. THIS FLT BEING A 'LIFEGUARD' MEDICAL FLT TRANSPORTING LONG PATIENT TO CLINIC; TIME WAS CRITICAL AND I GOT FOCUSED ON TKOF WITH PROPER TWR TKOF CLRNC. AFTERWARDS; CREW BRIEFED AND I INSTRUCTED COPLT TO BE MORE ASSERTIVE AND BE AGGRESSIVE AND TELL ME 'HOLD IN POS' UNTIL WE GET CLRNC FOR TKOF! IN SUMMARY: WHEN A PLT IS CLRED FOR 'TAXI INTO POS AND HOLD;' HE'S COCKED LIKE A 45 CALIBER REVOLVER READY TO RELEASE WITH THE TWR'S NEXT WORDS. WHEN TWR SAID RWY CONDITIONS; AND COPLT RESPONDED; I AUTOMATICALLY RELEASED BRAKES; ADDED PWR AND 'ROLLED;' JUST LIKE ALWAYS. I WAS FIXED ON THE TKOF AND PREDETERMINED TO GO WITH THE NEXT XMISSION FROM TWR!

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.