Narrative:

Widebody transport and large transport became traffic for each other in the middle of rbl high sector at FL350. When the aircraft were 40 NM apart my vector lines at 5 mins touched. Both aircraft were turned 10 degrees left. (Wind was reported 290 degrees at 87 KTS FL350.) this had no effect and C/a activated. I must add that at time of turn traffic was issued and reason for turn explained. Widebody transport reported traffic in sight. Both aircraft were now turned again 20 degrees left, but still no change in track of large transport, and very little change in widebody transport. Finally I had to turn both aircraft an additional 30 degrees left each and tell pilots to expedite. When aircraft were told to expedite is when I started seeing results of turn. I questioned another pilot on their procedure for turning an aircraft. He said it was normal to let their on board computer turn the aircraft, unless words such as 'immediate' or 'expedite' are used! I feel as a controller there needs to be more strict guidelines in this area of pilot/controller communication. When I turn an aircraft for traffic I'm not expecting it to take 2 mins to get to that heading. It's my opinion that pilots should use better judgement and turn the aircraft manually when traffic is the reason. As I understand it, when the computer turns the aircraft, it is somewhat less than the standard rate of turn!

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Original NASA ASRS Text

Title: TWO ACFT ON CONVERGING COURSES AT SAME ALT WERE ISSUED TURNS TO AVOID LOSS OF SEPARATION. STANDARD SEPARATION WAS MAINTAINED.

Narrative: WDB AND LGT BECAME TFC FOR EACH OTHER IN THE MIDDLE OF RBL HIGH SECTOR AT FL350. WHEN THE ACFT WERE 40 NM APART MY VECTOR LINES AT 5 MINS TOUCHED. BOTH ACFT WERE TURNED 10 DEGS LEFT. (WIND WAS RPTED 290 DEGS AT 87 KTS FL350.) THIS HAD NO EFFECT AND C/A ACTIVATED. I MUST ADD THAT AT TIME OF TURN TFC WAS ISSUED AND REASON FOR TURN EXPLAINED. WDB RPTED TFC IN SIGHT. BOTH ACFT WERE NOW TURNED AGAIN 20 DEGS LEFT, BUT STILL NO CHANGE IN TRACK OF LGT, AND VERY LITTLE CHANGE IN WDB. FINALLY I HAD TO TURN BOTH ACFT AN ADDITIONAL 30 DEGS LEFT EACH AND TELL PLTS TO EXPEDITE. WHEN ACFT WERE TOLD TO EXPEDITE IS WHEN I STARTED SEEING RESULTS OF TURN. I QUESTIONED ANOTHER PLT ON THEIR PROC FOR TURNING AN ACFT. HE SAID IT WAS NORMAL TO LET THEIR ON BOARD COMPUTER TURN THE ACFT, UNLESS WORDS SUCH AS 'IMMEDIATE' OR 'EXPEDITE' ARE USED! I FEEL AS A CTLR THERE NEEDS TO BE MORE STRICT GUIDELINES IN THIS AREA OF PLT/CTLR COM. WHEN I TURN AN ACFT FOR TFC I'M NOT EXPECTING IT TO TAKE 2 MINS TO GET TO THAT HDG. IT'S MY OPINION THAT PLTS SHOULD USE BETTER JUDGEMENT AND TURN THE ACFT MANUALLY WHEN TFC IS THE REASON. AS I UNDERSTAND IT, WHEN THE COMPUTER TURNS THE ACFT, IT IS SOMEWHAT LESS THAN THE STANDARD RATE OF TURN!

Data retrieved from NASA's ASRS site as of August 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.