Narrative:

The runway 8 LGL7V SID reads: follow extended runway centerline towards oye lctr utilizing ILS 26 (111.75 olw). At D2.5 ol turn right, intercept ol R-086 to D6.5 ol, turn right intercept clm R-249, turn right 'etc.' (this is a double-back procedure to take you west. It winds up paralleling runway 8 on the south side.) the first officer was flying using raw data. He had it in his mind that at the D2.5 ol he was to turn right to intercept the clm R-249. This he started to do. Before we were well into the turn, the departure controller told us to turn back left immediately to a heading of 060 degrees. She then said something in french. (We believe she was telling an opposite direction B747 to turn left immediately.) she then asked if we had visual contact with the B747. I answered yes as I had seen the aircraft before she asked us. He was (in my opinion) at least 1500-2000 ft below us and 2-3 mi distant. After he passed us the controller then gave us a right turn to 270 degrees to intercept the clm R-249. We never got any indication from TCASII that there was a conflict. I believe the B747 was an aircraft that departed the same runway immediately ahead of us on the same SID and transition. I am of the opinion that because the turn at D6.5 ol to intercept the clm R-249 is so tight that he overshot the radial and then went through it coming back to reintercept it placing him north of the radial and closer to us then he normally would have been. When we turned early, it really complicated things. To me, the wording on the SID is misleading. I think that instead of 'at D2.5 ol turn right, intercept ol R-086,' it would be better if it read 'at D2.5 ol, join the ol R-086,' etc. I say this because at that time you are literally on top of the radial. I think the words 'turn right' are what faked out the first officer.

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Original NASA ASRS Text

Title: SID MISINTERP. PF, FO, STARTED SID TURN EARLY AND CONFLICTED WITH OTHER DEPARTING TFC. CTLR INTERVENED AND KEPT SEPARATION.

Narrative: THE RWY 8 LGL7V SID READS: FOLLOW EXTENDED RWY CTRLINE TOWARDS OYE LCTR UTILIZING ILS 26 (111.75 OLW). AT D2.5 OL TURN R, INTERCEPT OL R-086 TO D6.5 OL, TURN R INTERCEPT CLM R-249, TURN R 'ETC.' (THIS IS A DOUBLE-BACK PROC TO TAKE YOU W. IT WINDS UP PARALLELING RWY 8 ON THE S SIDE.) THE FO WAS FLYING USING RAW DATA. HE HAD IT IN HIS MIND THAT AT THE D2.5 OL HE WAS TO TURN R TO INTERCEPT THE CLM R-249. THIS HE STARTED TO DO. BEFORE WE WERE WELL INTO THE TURN, THE DEP CTLR TOLD US TO TURN BACK L IMMEDIATELY TO A HDG OF 060 DEGS. SHE THEN SAID SOMETHING IN FRENCH. (WE BELIEVE SHE WAS TELLING AN OPPOSITE DIRECTION B747 TO TURN L IMMEDIATELY.) SHE THEN ASKED IF WE HAD VISUAL CONTACT WITH THE B747. I ANSWERED YES AS I HAD SEEN THE ACFT BEFORE SHE ASKED US. HE WAS (IN MY OPINION) AT LEAST 1500-2000 FT BELOW US AND 2-3 MI DISTANT. AFTER HE PASSED US THE CTLR THEN GAVE US A R TURN TO 270 DEGS TO INTERCEPT THE CLM R-249. WE NEVER GOT ANY INDICATION FROM TCASII THAT THERE WAS A CONFLICT. I BELIEVE THE B747 WAS AN ACFT THAT DEPARTED THE SAME RWY IMMEDIATELY AHEAD OF US ON THE SAME SID AND TRANSITION. I AM OF THE OPINION THAT BECAUSE THE TURN AT D6.5 OL TO INTERCEPT THE CLM R-249 IS SO TIGHT THAT HE OVERSHOT THE RADIAL AND THEN WENT THROUGH IT COMING BACK TO REINTERCEPT IT PLACING HIM N OF THE RADIAL AND CLOSER TO US THEN HE NORMALLY WOULD HAVE BEEN. WHEN WE TURNED EARLY, IT REALLY COMPLICATED THINGS. TO ME, THE WORDING ON THE SID IS MISLEADING. I THINK THAT INSTEAD OF 'AT D2.5 OL TURN R, INTERCEPT OL R-086,' IT WOULD BE BETTER IF IT READ 'AT D2.5 OL, JOIN THE OL R-086,' ETC. I SAY THIS BECAUSE AT THAT TIME YOU ARE LITERALLY ON TOP OF THE RADIAL. I THINK THE WORDS 'TURN R' ARE WHAT FAKED OUT THE FO.

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.