Narrative:

We were approach vny from the north to land, and had checked in with the local controller, advising of our position and altitude. He advised us to fly downwind for runway 34L. The controller then cleared a gulfstream for takeoff. We (there were 2 qualified pilots in the airplane) did not hear an altitude assignment or heading for the gulfstream, but after he took off, tower advised us of the gulfstream, and we advised he was in sight, and the pilot-rated passenger kept an eye on the gulfstream while I continued descent and set up for landing. At approximately 2500 ft MSL and 2.5 NM from the airport, the gulfstream turned towards us. We expected him to continue his climb, but he was nearly at our altitude, so I greatly increased the rate of descent. He passed just over and behind us. I was above traffic pattern altitude at the time (tpa is 1800 ft at vny), but was also a bit farther out than usual for tpa. We advised the tower of the incident, and he, the controller, indicated surprise and stated that they usually climb faster than that. This could have been prevented by the gulfstream pilot being made aware of our position and altitude as reported to the tower. The tower only asked if we had the gulfstream in sight, not vice-versa. It was particularly important this time, as his initial heading after takeoff was apparently right in our direction. Had we heard that heading assignment for the gulfstream, we probably would have ducked down much more quickly. It is unknown if the gulfstream had TCASII or if he saw us, but it was way too close for our comfort.

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Original NASA ASRS Text

Title: C206 PLT AND A GULFSTREAM BUSINESS JET HAD LESS THAN COMFORTABLE SEPARATION IN VNY CLASS D.

Narrative: WE WERE APCH VNY FROM THE N TO LAND, AND HAD CHKED IN WITH THE LCL CTLR, ADVISING OF OUR POS AND ALT. HE ADVISED US TO FLY DOWNWIND FOR RWY 34L. THE CTLR THEN CLRED A GULFSTREAM FOR TKOF. WE (THERE WERE 2 QUALIFIED PLTS IN THE AIRPLANE) DID NOT HEAR AN ALT ASSIGNMENT OR HDG FOR THE GULFSTREAM, BUT AFTER HE TOOK OFF, TWR ADVISED US OF THE GULFSTREAM, AND WE ADVISED HE WAS IN SIGHT, AND THE PLT-RATED PAX KEPT AN EYE ON THE GULFSTREAM WHILE I CONTINUED DSCNT AND SET UP FOR LNDG. AT APPROX 2500 FT MSL AND 2.5 NM FROM THE ARPT, THE GULFSTREAM TURNED TOWARDS US. WE EXPECTED HIM TO CONTINUE HIS CLB, BUT HE WAS NEARLY AT OUR ALT, SO I GREATLY INCREASED THE RATE OF DSCNT. HE PASSED JUST OVER AND BEHIND US. I WAS ABOVE TFC PATTERN ALT AT THE TIME (TPA IS 1800 FT AT VNY), BUT WAS ALSO A BIT FARTHER OUT THAN USUAL FOR TPA. WE ADVISED THE TWR OF THE INCIDENT, AND HE, THE CTLR, INDICATED SURPRISE AND STATED THAT THEY USUALLY CLB FASTER THAN THAT. THIS COULD HAVE BEEN PREVENTED BY THE GULFSTREAM PLT BEING MADE AWARE OF OUR POS AND ALT AS RPTED TO THE TWR. THE TWR ONLY ASKED IF WE HAD THE GULFSTREAM IN SIGHT, NOT VICE-VERSA. IT WAS PARTICULARLY IMPORTANT THIS TIME, AS HIS INITIAL HDG AFTER TKOF WAS APPARENTLY RIGHT IN OUR DIRECTION. HAD WE HEARD THAT HDG ASSIGNMENT FOR THE GULFSTREAM, WE PROBABLY WOULD HAVE DUCKED DOWN MUCH MORE QUICKLY. IT IS UNKNOWN IF THE GULFSTREAM HAD TCASII OR IF HE SAW US, BUT IT WAS WAY TOO CLOSE FOR OUR COMFORT.

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.