Narrative:

I was working an fgt making a practice hi-ILS approach. There was WX in the area with low ceiling and several decks of clouds. I noticed the fgt not making the turnout on the 13 mi arc, and advised him of this. As it sometimes happens, they have the wrong VORTAC dialed in. Anyway, the fgt said he was correcting to join the 13 mi arc. After a few seconds I asked the pilot of he wanted vectors to final. His mode C read 4000' descending. All of a sudden his mode C read 4500' climbing, and at the same time he was saying something like, 'I'm climbing to 100 for another approach.' (I'm not sure about what he said--I would have to listen to the tape to be sure.) as soon as he stopped talking I told him, 'negative, maintain 4000, turn right immediately heading 270,' and issued traffic which was a commercial medium large transport, 4 mi south of his position at 6000'. At this point his mode C read 5700' climbing. He did make the immediate right turn, but before descending his mode C read 6200'. I advised the pilot had dangerous the situation was. We then vectored the aircraft for the approach. I never lost the standard 3 mi sep, but this was only because of my quick action to turn him. I hate to think what might have happened if there was an aircraft right above him. I guess we could have violated the pilot, but we did not. I hope he learned something from my lecture.

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Original NASA ASRS Text

Title: ACFT ON APCH WAS OFF COURSE AND STARTED A CLIMB REQUIRING ATC INTERVENTION TO AVOID CONFLICT WITH ANOTHER ACFT.

Narrative: I WAS WORKING AN FGT MAKING A PRACTICE HI-ILS APCH. THERE WAS WX IN THE AREA WITH LOW CEILING AND SEVERAL DECKS OF CLOUDS. I NOTICED THE FGT NOT MAKING THE TURNOUT ON THE 13 MI ARC, AND ADVISED HIM OF THIS. AS IT SOMETIMES HAPPENS, THEY HAVE THE WRONG VORTAC DIALED IN. ANYWAY, THE FGT SAID HE WAS CORRECTING TO JOIN THE 13 MI ARC. AFTER A FEW SECS I ASKED THE PLT OF HE WANTED VECTORS TO FINAL. HIS MODE C READ 4000' DSNDING. ALL OF A SUDDEN HIS MODE C READ 4500' CLBING, AND AT THE SAME TIME HE WAS SAYING SOMETHING LIKE, 'I'M CLBING TO 100 FOR ANOTHER APCH.' (I'M NOT SURE ABOUT WHAT HE SAID--I WOULD HAVE TO LISTEN TO THE TAPE TO BE SURE.) AS SOON AS HE STOPPED TALKING I TOLD HIM, 'NEGATIVE, MAINTAIN 4000, TURN RIGHT IMMEDIATELY HDG 270,' AND ISSUED TFC WHICH WAS A COMMERCIAL MLG, 4 MI S OF HIS POS AT 6000'. AT THIS POINT HIS MODE C READ 5700' CLBING. HE DID MAKE THE IMMEDIATE RIGHT TURN, BUT BEFORE DSNDING HIS MODE C READ 6200'. I ADVISED THE PLT HAD DANGEROUS THE SITUATION WAS. WE THEN VECTORED THE ACFT FOR THE APCH. I NEVER LOST THE STANDARD 3 MI SEP, BUT THIS WAS ONLY BECAUSE OF MY QUICK ACTION TO TURN HIM. I HATE TO THINK WHAT MIGHT HAVE HAPPENED IF THERE WAS AN ACFT RIGHT ABOVE HIM. I GUESS WE COULD HAVE VIOLATED THE PLT, BUT WE DID NOT. I HOPE HE LEARNED SOMETHING FROM MY LECTURE.

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.