Narrative:

During climb out from laguardia airport, we had been cleared to climb and maintain 15000 ft. Departure control then revised the clearance, and asked us to maintain 11000 ft due to traffic ahead. The controller called the traffic at 2 O'clock and 7 mi. The aircraft was an mdt Y also on climb out. We visually sighted the aircraft, and reported it to the controller. He then cleared us to maintain visual separation, and climb to 15000 ft. The copilot was flying, and he began a gradual climb. I estimate that when we passed level with the mdt at about 12000 ft, we were 1/2 mi behind and slightly left of his course. As we passed abeam of the mdt, the pilot of that aircraft remarked that he thought we passed too close to him, and he didn't appreciate that we came that close. I estimate that at the time we passed, we were 800 ft vertically above and 2000 ft horizontally from him. I made at least 2 erroneous assumptions in this encounter. First, I assumed the mdt Y was on the same departure frequency, therefore he was aware that we were approaching from behind and we would be responsible for maintaining sep. As it turned out, once we were given the climb clearance, we were then given a different frequency. Apparently, the mdt crew were unaware of our presence as he was on the second frequency all along. The second bad assumption was that I was still able to accurately figure aircraft closure rates. Having last flown formation in pilot training some 18 yrs ago, I discovered I am no longer able to accurately gauge closure rates between aircraft. The midair collision that killed senator 'a' is a graphic example of what can happen when unskilled pilots attempt to use formation flying techniques. I made an error when I did not instruct the copilot to fly parallel to the mdt until well above him, or turn to pass wide to the right. The mdt pilot's not knowing of our presence may have contributed to an incident, as he may have begun a turn to the left, toward our flight path.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT WITH OVERTAKEN ACFT COMPLAINING ABOUT TFC SEP ON ACFT X VFR CLB THOUGH OCCUPIED ALT.

Narrative: DURING CLB OUT FROM LAGUARDIA ARPT, WE HAD BEEN CLRED TO CLB AND MAINTAIN 15000 FT. DEP CTL THEN REVISED THE CLRNC, AND ASKED US TO MAINTAIN 11000 FT DUE TO TFC AHEAD. THE CTLR CALLED THE TFC AT 2 O'CLOCK AND 7 MI. THE ACFT WAS AN MDT Y ALSO ON CLB OUT. WE VISUALLY SIGHTED THE ACFT, AND RPTED IT TO THE CTLR. HE THEN CLRED US TO MAINTAIN VISUAL SEPARATION, AND CLB TO 15000 FT. THE COPLT WAS FLYING, AND HE BEGAN A GRADUAL CLB. I ESTIMATE THAT WHEN WE PASSED LEVEL WITH THE MDT AT ABOUT 12000 FT, WE WERE 1/2 MI BEHIND AND SLIGHTLY L OF HIS COURSE. AS WE PASSED ABEAM OF THE MDT, THE PLT OF THAT ACFT REMARKED THAT HE THOUGHT WE PASSED TOO CLOSE TO HIM, AND HE DIDN'T APPRECIATE THAT WE CAME THAT CLOSE. I ESTIMATE THAT AT THE TIME WE PASSED, WE WERE 800 FT VERTICALLY ABOVE AND 2000 FT HORIZLY FROM HIM. I MADE AT LEAST 2 ERRONEOUS ASSUMPTIONS IN THIS ENCOUNTER. FIRST, I ASSUMED THE MDT Y WAS ON THE SAME DEP FREQ, THEREFORE HE WAS AWARE THAT WE WERE APCHING FROM BEHIND AND WE WOULD BE RESPONSIBLE FOR MAINTAINING SEP. AS IT TURNED OUT, ONCE WE WERE GIVEN THE CLB CLRNC, WE WERE THEN GIVEN A DIFFERENT FREQ. APPARENTLY, THE MDT CREW WERE UNAWARE OF OUR PRESENCE AS HE WAS ON THE SECOND FREQ ALL ALONG. THE SECOND BAD ASSUMPTION WAS THAT I WAS STILL ABLE TO ACCURATELY FIGURE ACFT CLOSURE RATES. HAVING LAST FLOWN FORMATION IN PLT TRAINING SOME 18 YRS AGO, I DISCOVERED I AM NO LONGER ABLE TO ACCURATELY GAUGE CLOSURE RATES BTWN ACFT. THE MIDAIR COLLISION THAT KILLED SENATOR 'A' IS A GRAPHIC EXAMPLE OF WHAT CAN HAPPEN WHEN UNSKILLED PLTS ATTEMPT TO USE FORMATION FLYING TECHNIQUES. I MADE AN ERROR WHEN I DID NOT INSTRUCT THE COPLT TO FLY PARALLEL TO THE MDT UNTIL WELL ABOVE HIM, OR TURN TO PASS WIDE TO THE R. THE MDT PLT'S NOT KNOWING OF OUR PRESENCE MAY HAVE CONTRIBUTED TO AN INCIDENT, AS HE MAY HAVE BEGUN A TURN TO THE L, TOWARD OUR FLT PATH.

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.