Narrative:

We received a clearance to depart yxu on the london SID. Our clearance was to takeoff and contact toronto center after liftoff. We were climbing to 4000 ft and since we did not receive a runway heading clearance from yxu tower I mistakenly thought we were cleared on course. If I had looked at the SID more closely I would have discovered that we were to fly runway heading to 4000 ft and wait for radar vectors. My error was discovered when toronto center asked what heading we were turning to. We advised him of the present heading and he leveled us at 3000 ft and we stayed on our present heading. The only traffic we detected, showed on TCASII at our 2 O'clock position, 7 mi and 5000 ft MSL. We apparently did not cause any direct conflict other than his planning. We had been on duty for 4 hours and this was my 3RD day of 4. One other minor distraction was a ground problem causing us to be 20 mins late departing. This confrontation before departing dtw was on my mind but I should not have let it distract me.

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Original NASA ASRS Text

Title: COMMUTER PIC PERFORMS A HDG TRACK POS DEV WHEN MISINTERP THE SID DEP PROC. NON ADHERENCE TO ATC CLRNC PROC.

Narrative: WE RECEIVED A CLRNC TO DEPART YXU ON THE LONDON SID. OUR CLRNC WAS TO TKOF AND CONTACT TORONTO CTR AFTER LIFTOFF. WE WERE CLBING TO 4000 FT AND SINCE WE DID NOT RECEIVE A RWY HDG CLRNC FROM YXU TWR I MISTAKENLY THOUGHT WE WERE CLRED ON COURSE. IF I HAD LOOKED AT THE SID MORE CLOSELY I WOULD HAVE DISCOVERED THAT WE WERE TO FLY RWY HDG TO 4000 FT AND WAIT FOR RADAR VECTORS. MY ERROR WAS DISCOVERED WHEN TORONTO CTR ASKED WHAT HDG WE WERE TURNING TO. WE ADVISED HIM OF THE PRESENT HDG AND HE LEVELED US AT 3000 FT AND WE STAYED ON OUR PRESENT HDG. THE ONLY TFC WE DETECTED, SHOWED ON TCASII AT OUR 2 O'CLOCK POS, 7 MI AND 5000 FT MSL. WE APPARENTLY DID NOT CAUSE ANY DIRECT CONFLICT OTHER THAN HIS PLANNING. WE HAD BEEN ON DUTY FOR 4 HRS AND THIS WAS MY 3RD DAY OF 4. ONE OTHER MINOR DISTR WAS A GND PROB CAUSING US TO BE 20 MINS LATE DEPARTING. THIS CONFRONTATION BEFORE DEPARTING DTW WAS ON MY MIND BUT I SHOULD NOT HAVE LET IT DISTRACT ME.

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.