Narrative:

On departure we were given a 090 degree heading which would have taken us into a thunderstorm cell east of the field. This cell was painting on radar. We asked for a left turn to avoid the cell and were told not to continue 090 degrees and go to departure control. We came within 3-5 mi of the cell and turned right to 140 degrees to avoid it and informed departure control of our heading. We probably should have tried to coordinate a heading with tower prior to takeoff roll. No TCASII alerts were received. Supplemental information from acn 481425: cleared for takeoff and instructed to fly a 090 degree heading after takeoff. We advised tower after liftoff that we would need a heading of 060 degrees to avoid WX (thunderstorm cell showing on radar and from cockpit). Tower advised he could not assign a 060 degree heading and for us to remain on a 090 degree heading and contact departure control. We switched to departure and advised them that we were turning to a 140 degree heading and would advise when we could turn back to a 090 degree heading. We remained VFR until we were established on the 140 degree heading. We never received a TCASII alert nor saw any aircraft close (1-2 mi) to our position. This occurrence would have been less confusing if we had coordinated a heading for WX before we started our takeoff roll.

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Original NASA ASRS Text

Title: FK10 CREW AVOIDED PENETRATING A TSTM IN C90 CLASS B AIRSPACE.

Narrative: ON DEP WE WERE GIVEN A 090 DEG HDG WHICH WOULD HAVE TAKEN US INTO A TSTM CELL E OF THE FIELD. THIS CELL WAS PAINTING ON RADAR. WE ASKED FOR A L TURN TO AVOID THE CELL AND WERE TOLD NOT TO CONTINUE 090 DEGS AND GO TO DEP CTL. WE CAME WITHIN 3-5 MI OF THE CELL AND TURNED R TO 140 DEGS TO AVOID IT AND INFORMED DEP CTL OF OUR HDG. WE PROBABLY SHOULD HAVE TRIED TO COORDINATE A HDG WITH TWR PRIOR TO TKOF ROLL. NO TCASII ALERTS WERE RECEIVED. SUPPLEMENTAL INFO FROM ACN 481425: CLRED FOR TKOF AND INSTRUCTED TO FLY A 090 DEG HDG AFTER TKOF. WE ADVISED TWR AFTER LIFTOFF THAT WE WOULD NEED A HDG OF 060 DEGS TO AVOID WX (TSTM CELL SHOWING ON RADAR AND FROM COCKPIT). TWR ADVISED HE COULD NOT ASSIGN A 060 DEG HDG AND FOR US TO REMAIN ON A 090 DEG HDG AND CONTACT DEP CTL. WE SWITCHED TO DEP AND ADVISED THEM THAT WE WERE TURNING TO A 140 DEG HDG AND WOULD ADVISE WHEN WE COULD TURN BACK TO A 090 DEG HDG. WE REMAINED VFR UNTIL WE WERE ESTABLISHED ON THE 140 DEG HDG. WE NEVER RECEIVED A TCASII ALERT NOR SAW ANY ACFT CLOSE (1-2 MI) TO OUR POS. THIS OCCURRENCE WOULD HAVE BEEN LESS CONFUSING IF WE HAD COORDINATED A HDG FOR WX BEFORE WE STARTED OUR TKOF ROLL.

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.