Narrative:

Our flight, medium large transport X on july 1990, was involved in a loss of sep while departing runway 24L at yyz. About 45 seconds after a medium large transport Y was cleared for takeoff (from this runway) we were cleared for an immediate takeoff (there was a widebody transport on about a 3 mi final). Upon contacting toronto departure control we were issued the clearance of 'climb to 7000', upon reaching 3600' turn to 140 degree heading.' just as we were passing through 3600' MSL I was beginning to increase thrust from the 'quite EPR' setting to 'climb power.' also I was beginning to accelerate from 191 KTS (the zero flap maneuvering speed) to 250 KTS and begin my turn to 140 degrees. As I lowered the nose to accelerate I noticed that the medium large transport Y that had departed prior to us was at 12 O'clock, at about our same altitude. The departure controller then asked if we saw this aircraft, then said, 'maintain 4000'' we were just beginning to make our turn to 140 degrees and I thought that I could 'turn inside' of the other jet but noticed that he also was beginning a left turn, perhaps to a 140 degree heading. I maintained 4000' and turned slightly to the right to avoid getting too close the this aircraft. If I had turned to 140 degrees our flight paths would have converged. As it was, we had about 1 mi lateral sep and about 800' vertically.

Related reports:

Google
 

Original NASA ASRS Text

Title: A DEPARTING ACFT OVERTOOK A PRECEDING DEP WHICH RESULTED IN LESS THAN STANDARD SEPARATION.

Narrative: OUR FLT, MLG X ON JULY 1990, WAS INVOLVED IN A LOSS OF SEP WHILE DEPARTING RWY 24L AT YYZ. ABOUT 45 SECS AFTER A MLG Y WAS CLRED FOR TKOF (FROM THIS RWY) WE WERE CLRED FOR AN IMMEDIATE TKOF (THERE WAS A WDB ON ABOUT A 3 MI FINAL). UPON CONTACTING TORONTO DEP CTL WE WERE ISSUED THE CLRNC OF 'CLB TO 7000', UPON REACHING 3600' TURN TO 140 DEG HDG.' JUST AS WE WERE PASSING THROUGH 3600' MSL I WAS BEGINNING TO INCREASE THRUST FROM THE 'QUITE EPR' SETTING TO 'CLB PWR.' ALSO I WAS BEGINNING TO ACCELERATE FROM 191 KTS (THE ZERO FLAP MANEUVERING SPD) TO 250 KTS AND BEGIN MY TURN TO 140 DEGS. AS I LOWERED THE NOSE TO ACCELERATE I NOTICED THAT THE MLG Y THAT HAD DEPARTED PRIOR TO US WAS AT 12 O'CLOCK, AT ABOUT OUR SAME ALT. THE DEP CTLR THEN ASKED IF WE SAW THIS ACFT, THEN SAID, 'MAINTAIN 4000'' WE WERE JUST BEGINNING TO MAKE OUR TURN TO 140 DEGS AND I THOUGHT THAT I COULD 'TURN INSIDE' OF THE OTHER JET BUT NOTICED THAT HE ALSO WAS BEGINNING A LEFT TURN, PERHAPS TO A 140 DEG HDG. I MAINTAINED 4000' AND TURNED SLIGHTLY TO THE R TO AVOID GETTING TOO CLOSE THE THIS ACFT. IF I HAD TURNED TO 140 DEGS OUR FLT PATHS WOULD HAVE CONVERGED. AS IT WAS, WE HAD ABOUT 1 MI LATERAL SEP AND ABOUT 800' VERTICALLY.

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.