Narrative:

The first officer briefed the routing as radar vectors to the mead 8 departure, peach springs transition (mead 8.pgs). Prior to pushback, while the first officer was getting the clearance, I had been helping the senior flight attendant and operations agent tag passenger bags and cockpit observer bags for storage in the cargo compartment. On taxi out, again quickly reviewed our departure clearance. Las was departing from runway 1R, which is not the norm. I, though, have an uncomfortable feeling about the departure, since both it and the single-engine procedure were different from the runway 25R procedure with which I was very familiar. At 1.8 NM north of the departure end of runway 1R, the tower controller said, 'start your turn to the 070 degree heading. That's the same heading one would fly if already on the pgs transition. Now was this a non-standard terminology to 'resume' or 'join' the SID, or in fact, just an assigned heading? I think the only reason I would have considered this was because I was not totally confident I understood the first officer's briefing. Passing 5200 ft MSL, I asked the first officer to ask departure control for a clarification. However, at that moment, departure became very busy and we couldn't get a word in edge-wise. I started a 10 degree banked right turn to direct bld as called for in the SID. I hoped that if they wanted the turn, I'd be in it and if they didn't, I wouldn't have turned enough to cause a problem or be able to turn back without much change in position. After approximately 20 degrees of turn, departure asked if we were turning directly to bld. We said we were and he then asked if we were assigned a heading for departure. The radio xmissions were then clipped by one another in attempts to recover on our part and chastise on departure's part. We were then cleared direct bld with an expedited climb through 8000 ft. We complied. When the frequency cleared, I explained to him what I had done and why. Had I spent more time thinking about the departure prior to push back, I'd have realized that, since las was accepting 25 arrs upon pilot request, an easterly heading during climb out was to get us above any inbound arrs. My failure to properly understand the assigned departure procedure resulted in this error.

Related reports:

Google
 

Original NASA ASRS Text

Title: TRACK DEV.

Narrative: THE FO BRIEFED THE ROUTING AS RADAR VECTORS TO THE MEAD 8 DEP, PEACH SPRINGS TRANSITION (MEAD 8.PGS). PRIOR TO PUSHBACK, WHILE THE FO WAS GETTING THE CLRNC, I HAD BEEN HELPING THE SENIOR FLT ATTENDANT AND OPS AGENT TAG PAX BAGS AND COCKPIT OBSERVER BAGS FOR STORAGE IN THE CARGO COMPARTMENT. ON TAXI OUT, AGAIN QUICKLY REVIEWED OUR DEP CLRNC. LAS WAS DEPARTING FROM RWY 1R, WHICH IS NOT THE NORM. I, THOUGH, HAVE AN UNCOMFORTABLE FEELING ABOUT THE DEP, SINCE BOTH IT AND THE SINGLE-ENG PROC WERE DIFFERENT FROM THE RWY 25R PROC WITH WHICH I WAS VERY FAMILIAR. AT 1.8 NM N OF THE DEP END OF RWY 1R, THE TWR CTLR SAID, 'START YOUR TURN TO THE 070 DEG HDG. THAT'S THE SAME HDG ONE WOULD FLY IF ALREADY ON THE PGS TRANSITION. NOW WAS THIS A NON-STANDARD TERMINOLOGY TO 'RESUME' OR 'JOIN' THE SID, OR IN FACT, JUST AN ASSIGNED HDG? I THINK THE ONLY REASON I WOULD HAVE CONSIDERED THIS WAS BECAUSE I WAS NOT TOTALLY CONFIDENT I UNDERSTOOD THE FO'S BRIEFING. PASSING 5200 FT MSL, I ASKED THE FO TO ASK DEP CTL FOR A CLARIFICATION. HOWEVER, AT THAT MOMENT, DEP BECAME VERY BUSY AND WE COULDN'T GET A WORD IN EDGE-WISE. I STARTED A 10 DEG BANKED R TURN TO DIRECT BLD AS CALLED FOR IN THE SID. I HOPED THAT IF THEY WANTED THE TURN, I'D BE IN IT AND IF THEY DIDN'T, I WOULDN'T HAVE TURNED ENOUGH TO CAUSE A PROB OR BE ABLE TO TURN BACK WITHOUT MUCH CHANGE IN POS. AFTER APPROX 20 DEGS OF TURN, DEP ASKED IF WE WERE TURNING DIRECTLY TO BLD. WE SAID WE WERE AND HE THEN ASKED IF WE WERE ASSIGNED A HDG FOR DEP. THE RADIO XMISSIONS WERE THEN CLIPPED BY ONE ANOTHER IN ATTEMPTS TO RECOVER ON OUR PART AND CHASTISE ON DEP'S PART. WE WERE THEN CLRED DIRECT BLD WITH AN EXPEDITED CLB THROUGH 8000 FT. WE COMPLIED. WHEN THE FREQ CLRED, I EXPLAINED TO HIM WHAT I HAD DONE AND WHY. HAD I SPENT MORE TIME THINKING ABOUT THE DEP PRIOR TO PUSH BACK, I'D HAVE REALIZED THAT, SINCE LAS WAS ACCEPTING 25 ARRS UPON PLT REQUEST, AN EASTERLY HDG DURING CLBOUT WAS TO GET US ABOVE ANY INBOUND ARRS. MY FAILURE TO PROPERLY UNDERSTAND THE ASSIGNED DEP PROC RESULTED IN THIS ERROR.

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.