Narrative:

I filed an IFR flight plan into a pre-arranged test area between hfd and een. The flight test runs, starting 40 NM northeast of hfd sbound, consisted of level steep bank turns of varying turn distances at FL260. Only restrictions ZBW had was to notify them at the end of each sbound run when turning north to start the test run again. We started run #5 sbound. ZBW asked us how much longer we would be making these orbits today. We answered that we would be making 2 more runs. We were heading 280 degrees magnetic and just starting a left 60 degree bank turn when center cleared air carrier flight to turn left 15 degrees and to climb to FL390. Center then said to us that he needed to know when we make our turns. This is the first time they had made this request. We stated that we were in our turn and passing through heading 195 degrees. Center asked us to turn left (which we were already doing). Approximately 5 seconds later, we were done with the maneuver and rolled out on a true heading of 152 degrees. During that 5 seconds, center asked air carrier to turn to a heading of 320 degrees and to expedite through FL270. Then center said to air carrier to turn right immediately and then to expedite through FL270 again. Approximately 5 seconds later, center cleared air carrier direct to baf and thanked them for their help. Sometime during those past 10 seconds air carrier and we got pretty close together, although we did not see each other. I believe the problem was that we had been doing the same maneuver for the previous runs but on this run we changed the maneuver slightly, holding the 60 degree bank turns for a longer time than previous runs. I feel ATC anticipated the same type maneuver as before and cleared traffic through an area that we were going to use during that particular run and through airspace that should have been clear of all traffic.

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Original NASA ASRS Text

Title: EXPERIMENTAL MLG ON TEST FLT HAS NMAC WITH ACR.

Narrative: I FILED AN IFR FLT PLAN INTO A PRE-ARRANGED TEST AREA BTWN HFD AND EEN. THE FLT TEST RUNS, STARTING 40 NM NE OF HFD SBOUND, CONSISTED OF LEVEL STEEP BANK TURNS OF VARYING TURN DISTANCES AT FL260. ONLY RESTRICTIONS ZBW HAD WAS TO NOTIFY THEM AT THE END OF EACH SBOUND RUN WHEN TURNING N TO START THE TEST RUN AGAIN. WE STARTED RUN #5 SBOUND. ZBW ASKED US HOW MUCH LONGER WE WOULD BE MAKING THESE ORBITS TODAY. WE ANSWERED THAT WE WOULD BE MAKING 2 MORE RUNS. WE WERE HDG 280 DEGS MAGNETIC AND JUST STARTING A L 60 DEG BANK TURN WHEN CTR CLRED ACR FLT TO TURN L 15 DEGS AND TO CLB TO FL390. CTR THEN SAID TO US THAT HE NEEDED TO KNOW WHEN WE MAKE OUR TURNS. THIS IS THE FIRST TIME THEY HAD MADE THIS REQUEST. WE STATED THAT WE WERE IN OUR TURN AND PASSING THROUGH HDG 195 DEGS. CTR ASKED US TO TURN L (WHICH WE WERE ALREADY DOING). APPROX 5 SECONDS LATER, WE WERE DONE WITH THE MANEUVER AND ROLLED OUT ON A TRUE HDG OF 152 DEGS. DURING THAT 5 SECONDS, CTR ASKED ACR TO TURN TO A HDG OF 320 DEGS AND TO EXPEDITE THROUGH FL270. THEN CTR SAID TO ACR TO TURN R IMMEDIATELY AND THEN TO EXPEDITE THROUGH FL270 AGAIN. APPROX 5 SECONDS LATER, CTR CLRED ACR DIRECT TO BAF AND THANKED THEM FOR THEIR HELP. SOMETIME DURING THOSE PAST 10 SECONDS ACR AND WE GOT PRETTY CLOSE TOGETHER, ALTHOUGH WE DID NOT SEE EACH OTHER. I BELIEVE THE PROB WAS THAT WE HAD BEEN DOING THE SAME MANEUVER FOR THE PREVIOUS RUNS BUT ON THIS RUN WE CHANGED THE MANEUVER SLIGHTLY, HOLDING THE 60 DEG BANK TURNS FOR A LONGER TIME THAN PREVIOUS RUNS. I FEEL ATC ANTICIPATED THE SAME TYPE MANEUVER AS BEFORE AND CLRED TFC THROUGH AN AREA THAT WE WERE GOING TO USE DURING THAT PARTICULAR RUN AND THROUGH AIRSPACE THAT SHOULD HAVE BEEN CLR OF ALL TFC.

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.