SUCCESSIVE DEP INCIDENT AT BWI.

Narrative

MY WIFE AND I SAW 2 PLANES ALMOST COLLIDE DURING CLBOUT FROM BWI ON APR/WED/03 AT XA21 LCL; WHILE WE WERE DRIVING ALONG THE BALTIMORE-WASHINGTON PARKWAY (MD-295) ON OUR WAY TO BWI ARPT. A COMMERCIAL MD90 WAS IN A SLIGHT CLBING TURN TO THE L AFTER TKOF; ABOUT 2-3 MI DOWNRANGE; AT APPROX 2500 FT AGL; WHEN A SMALL BUSINESS JET (PROBABLY LEAR JET) PASSED WITHIN A FEW HUNDRED FT OF SEPARATION; AND THROUGH; CO-ALT WITH THE MD90. THE BUSINESS JET APCHED THE MD90 FROM THE 5 O'CLOCK POS AND ALMOST APPEARED AS IF IT WAS TRYING TO FLY IN TRAIL FORMATION; MOMENTARILY; WITH THE MD90. THE BUSINESS JET PASSED TO THE REAR OF THE MD90 FROM R TO L; AND PASSED THROUGH CO-ALT WHILE CONTINUING TO CLB AND ACCELERATE PAST THE MD90. THE AIRSPD OF THE BUSINESS JET EXCEEDED THAT OF THE MD90; PASSING ABOVE AND TO THE L OF THE MD90 AT THE 11 O'CLOCK POS. THE BUSINESS JET APPEARED TO BE MANEUVERING AWAY FROM THE MD90 BY TURNING INSIDE; AND CLBING WHEN WE WERE NO LONGER ABLE TO OBSERVE THE INCIDENT DUE TO THE TREE CANOPY. IT APPEARS THE TWR CLRED BOTH ACFT FOR TKOF AT NEARLY THE SAME TIME; OR THE BUSINESS JET FAILED TO HOLD LONG ENOUGH FOR DEP; AND THE ACCELERATION WAS GREAT ENOUGH TO OVERTAKE THE MD90 AFTER DELAYING DEP. IT APPEARS POSSIBLE THAT BOTH ACFT WERE CLRED FOR TKOF FROM THE SAME RWY (RWY 28) OR PARALLEL RWYS (RWY 33L FOR THE MD90 AND RWY 33R FOR THE BUSINESS JET). ANOTHER POSSIBILITY IS THAT ONE WAS CLRED FOR DEP ON RWY 28 AND ANOTHER WAS ON RWY 33L. IN ANY CASE; THE INCIDENT SEEMED TO BE CAUSED BY THE DEP CTLR; AND WAS NOT AVOIDED BY THE BUSINESS JET PLT; WHO HAD A CLR VISUAL VIEW OF THE MD90. THE BUSINESS JET SHOULD HAVE TURNED TO THE R AND DECREASED ALT TO AVOID THE MD90. THE CTLR COULD HAVE GIVEN INCORRECT DEP VECTORING AND/OR DEP CLRNC INSTRUCTIONS TO EITHER ACFT OR; DID NOT DELAY DEP FOR THE BUSINESS JET AFTER THE SLOWER MD90 DEPARTED. IF THE BUSINESS JET WAS DEPARTING ON INSTS; THE VISUAL DETECTION OF THE MD90 COULD HAVE BEEN MORE DIFFICULT; BUT CONDITIONS AT THE TIME WERE EXCELLENT FOR VISUAL CONTACT. SUN POS DID NOT SEEM TO BE A FACTOR.