Narrative:

I should not have been in such a hurry to offer IFR clearance until I knew the actual speed and direction of aircraft X; even though I did it because I believed aircraft would have trouble maintaining VFR. If pilot had turned at standard rate or better; error would not have occurred. I was working sector 33 when aircraft X (an ajet) checked on at XA46:13; VFR; requesting IFR clearance to nzy. I told pilot at XA46:25 to squawk XXXX and maintain VFR. At XA46:48 I idented target; told pilot 'radar contact' and asked pilot if he could maintain VFR until reaching 2000 ft (the mia in that area). The pilot stated 'just barely can; uh; do that sir; yes sir.' I did not sound convinced; so I asked pilot if he could maintain his own terrain and obstruction clearance until reaching 2000 ft. The pilot said he could; and I issued him a clearance to nzy via sea; then as filed; and to fly heading 130 degrees and maintain 2000 ft (at time XA47:03). I then observed target heading west; instead of southeast; and told pilot to turn heading 070 degrees (at time XA47:30). At XA47:54 I asked pilot of aircraft X to verify heading 070 degrees. He stated 'in the l-hand turn not there yet.' I called traffic for aircraft X at XA48:00 to try to get traffic in sight; and utilize visual separation; but was unsuccessful.

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Original NASA ASRS Text

Title: ZSE CTLR EXPERIENCED OPERROR AT 2500 FT WHEN THE ISSUANCE OF AN IFR CLRNC TO A MIL ACFT; IN MVFR CONDITIONS; RESULTED IN UNEXPECTED TURNS.

Narrative: I SHOULD NOT HAVE BEEN IN SUCH A HURRY TO OFFER IFR CLRNC UNTIL I KNEW THE ACTUAL SPD AND DIRECTION OF ACFT X; EVEN THOUGH I DID IT BECAUSE I BELIEVED ACFT WOULD HAVE TROUBLE MAINTAINING VFR. IF PLT HAD TURNED AT STANDARD RATE OR BETTER; ERROR WOULD NOT HAVE OCCURRED. I WAS WORKING SECTOR 33 WHEN ACFT X (AN AJET) CHKED ON AT XA46:13; VFR; REQUESTING IFR CLRNC TO NZY. I TOLD PLT AT XA46:25 TO SQUAWK XXXX AND MAINTAIN VFR. AT XA46:48 I IDENTED TARGET; TOLD PLT 'RADAR CONTACT' AND ASKED PLT IF HE COULD MAINTAIN VFR UNTIL REACHING 2000 FT (THE MIA IN THAT AREA). THE PLT STATED 'JUST BARELY CAN; UH; DO THAT SIR; YES SIR.' I DID NOT SOUND CONVINCED; SO I ASKED PLT IF HE COULD MAINTAIN HIS OWN TERRAIN AND OBSTRUCTION CLRNC UNTIL REACHING 2000 FT. THE PLT SAID HE COULD; AND I ISSUED HIM A CLRNC TO NZY VIA SEA; THEN AS FILED; AND TO FLY HDG 130 DEGS AND MAINTAIN 2000 FT (AT TIME XA47:03). I THEN OBSERVED TARGET HEADING W; INSTEAD OF SE; AND TOLD PLT TO TURN HDG 070 DEGS (AT TIME XA47:30). AT XA47:54 I ASKED PLT OF ACFT X TO VERIFY HDG 070 DEGS. HE STATED 'IN THE L-HAND TURN NOT THERE YET.' I CALLED TFC FOR ACFT X AT XA48:00 TO TRY TO GET TFC IN SIGHT; AND UTILIZE VISUAL SEPARATION; BUT WAS UNSUCCESSFUL.

Data retrieved from NASA's ASRS site as of January 2009 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.