Narrative:

Level 12000, ny approach called air carrier medium large transport traffic, 8 O'clock (or so) 10 mi, climbing to 11000. We responded 'no joy.' then ATC called medium large transport 6 mi, 11000. We again responded 'no joy.' then ATC told us 'the medium large transport had us in sight, was maintaining visual, climbing to 17000. No problem.' shortly thereafter, I look out the left window, and there goes the medium large transport almost directly overhead, and quite close. I asked ATC what the vertical separation was, and the answer was '400 ft.' (medium large transport came from behind -- overtook us). I turned right about 45 degrees to avoid any wake turbulence, and told ATC as much. They said 'approved.' filed near miss the next day. I sincerely hope that the other aircraft wasn't trying to give us a scare, because that could cost them their jobs. Supplemental information from acn 200299. After having departed runway 4 at lga, we were given a heading of 270 degrees and climb to 10000. At 10000 ft and 250 KTS we were cleared to 11000 ft. Traffic was called at our 1 O'clock at 12000 -- an engined turbo propeller mdt. The captain saw the traffic and acknowledged it 5-6 mi away. I was hand flying and concentrating on the level off at 11000 ft. I decided to engage the autoplt so I could scan outside easier. I then visually acquired the traffic. Departure then told us to maintain visual separation with the mdt and climb to 15000. I simultaneously began an acceleration to 300 KTS and using the vs mode commanded a climb to 15000 at 2000 FPM. The climb and acceleration were smooth, but slow. The mdt initially appeared to be moving right to left and I judged we would pass behind the aircraft during the climb. The mdt was not on our frequency. Then, either the mdt turned from southwest to west or my initial perception of the direction was incorrect. I made the comment to the captain 'this looks too close' so I made a 10 degree left correction, confused as to what 'maintain visual separation' really allowed me to do. Could I turn legally, was there another aircraft to my left, how did we overtake this aircraft so rapidly? I immediately commanded 2500 ft up on vs. We passed left of the mdt less than 1000 ft and about 6-800 ft above. We were on parallel headings.

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Original NASA ASRS Text

Title: NMAC BTWN 2 DEP ACFT SAME DIRECTION TFC.

Narrative: LEVEL 12000, NY APCH CALLED ACR MLG TFC, 8 O'CLOCK (OR SO) 10 MI, CLBING TO 11000. WE RESPONDED 'NO JOY.' THEN ATC CALLED MLG 6 MI, 11000. WE AGAIN RESPONDED 'NO JOY.' THEN ATC TOLD US 'THE MLG HAD US IN SIGHT, WAS MAINTAINING VISUAL, CLBING TO 17000. NO PROBLEM.' SHORTLY THEREAFTER, I LOOK OUT THE L WINDOW, AND THERE GOES THE MLG ALMOST DIRECTLY OVERHEAD, AND QUITE CLOSE. I ASKED ATC WHAT THE VERT SEPARATION WAS, AND THE ANSWER WAS '400 FT.' (MLG CAME FROM BEHIND -- OVERTOOK US). I TURNED R ABOUT 45 DEGS TO AVOID ANY WAKE TURB, AND TOLD ATC AS MUCH. THEY SAID 'APPROVED.' FILED NEAR MISS THE NEXT DAY. I SINCERELY HOPE THAT THE OTHER ACFT WASN'T TRYING TO GIVE US A SCARE, BECAUSE THAT COULD COST THEM THEIR JOBS. SUPPLEMENTAL INFO FROM ACN 200299. AFTER HAVING DEPARTED RWY 4 AT LGA, WE WERE GIVEN A HDG OF 270 DEGS AND CLB TO 10000. AT 10000 FT AND 250 KTS WE WERE CLRED TO 11000 FT. TFC WAS CALLED AT OUR 1 O'CLOCK AT 12000 -- AN ENGINED TURBO PROP MDT. THE CAPT SAW THE TFC AND ACKNOWLEDGED IT 5-6 MI AWAY. I WAS HAND FLYING AND CONCENTRATING ON THE LEVEL OFF AT 11000 FT. I DECIDED TO ENGAGE THE AUTOPLT SO I COULD SCAN OUTSIDE EASIER. I THEN VISUALLY ACQUIRED THE TFC. DEP THEN TOLD US TO MAINTAIN VISUAL SEPARATION WITH THE MDT AND CLB TO 15000. I SIMULTANEOUSLY BEGAN AN ACCELERATION TO 300 KTS AND USING THE VS MODE COMMANDED A CLB TO 15000 AT 2000 FPM. THE CLB AND ACCELERATION WERE SMOOTH, BUT SLOW. THE MDT INITIALLY APPEARED TO BE MOVING R TO L AND I JUDGED WE WOULD PASS BEHIND THE ACFT DURING THE CLB. THE MDT WAS NOT ON OUR FREQ. THEN, EITHER THE MDT TURNED FROM SW TO W OR MY INITIAL PERCEPTION OF THE DIRECTION WAS INCORRECT. I MADE THE COMMENT TO THE CAPT 'THIS LOOKS TOO CLOSE' SO I MADE A 10 DEG L CORRECTION, CONFUSED AS TO WHAT 'MAINTAIN VISUAL SEPARATION' REALLY ALLOWED ME TO DO. COULD I TURN LEGALLY, WAS THERE ANOTHER ACFT TO MY L, HOW DID WE OVERTAKE THIS ACFT SO RAPIDLY? I IMMEDIATELY COMMANDED 2500 FT UP ON VS. WE PASSED L OF THE MDT LESS THAN 1000 FT AND ABOUT 6-800 FT ABOVE. WE WERE ON PARALLEL HDGS.

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.