Narrative:

Aircraft X was on ILS 6 approach to london airport (loz) and had just been cleared when they started flashing with an aircraft that was VFR unidentified (VFR1). I saw no reason to call traffic because aircraft X had no turned onto the localizer and VFR1 was flying away from the airport. They stopped flashing but I kept an eye on VFR1. A couple minutes later I noticed VFR1 was on a heading that would cross the localizer at 027 altitude. I called the traffic and informed the pilot that I did not think traffic was a factor because VFR1 would cross localizer and be out in front of him by 2 miles. I started a track on VFR1 and noticed it was turning directly up the localizer. I did a traffic alert; and advised aircraft X to stop his descent. The pilot complied and leveled at 032; which is 500 feet below the MVA. I thought maybe they would fly over VFR1 because at that time VFR1 was level at 027. I then saw VFR1 begin to climb so I told aircraft X to turn 40 degrees left and called the traffic. Pilot complied and after one more traffic call; got VFR1 insight within 1 mile and several hundred feet altitude. Pilot said VFR1 was turning into him and asked to turn other direction. I said 'approved' once they were clear I offered to climb the pilot back up and vector back out to the approach to start over but the pilot said they were ok and were ready to cancel IFR. I know I did several things against regulations here. 1. Never cancelled his approach clearance. -Never thought about it until after it was over. With VFR1 maneuvering around in unpredictable pattern; I just did what I felt I needed to do to prevent collision. Cancelling approach clearances is something hardly ever done in center environment; and the procedures for what to do just did not come naturally in the moment. 2. Turned below MVA - again; I just did what I thought I had to do. I would deal with the MVA once I felt the planes were separated.3. I just did not know what to do once the planes were clear. I knew aircraft X was below the MVA and was not sure how to properly address the issue other than ask the pilot if they could get back on the localizer and land safely; or if they wanted to climb and start from the beginning.there is no way to prevent this from happening; but we need to review how to handle traffic alert situations below the MVA. It may have been covered; but in practicality we never see it.

Related reports:

Google
 

Original NASA ASRS Text

Title: ZID Controller reported a BE35 on an ILS approach was in conflict with non-participating VFR traffic; requiring an avoidance vector below the Minimum Vectoring Altitude.

Narrative: Aircraft X was on ILS 6 approach to London airport (LOZ) and had just been cleared when they started flashing with an aircraft that was VFR unidentified (VFR1). I saw no reason to call traffic because Aircraft X had no turned onto the localizer and VFR1 was flying away from the airport. They stopped flashing but I kept an eye on VFR1. A couple minutes later I noticed VFR1 was on a heading that would cross the localizer at 027 altitude. I called the traffic and informed the pilot that I did not think traffic was a factor because VFR1 would cross localizer and be out in front of him by 2 miles. I started a track on VFR1 and noticed it was turning directly up the localizer. I did a traffic alert; and advised Aircraft X to stop his descent. The pilot complied and leveled at 032; which is 500 feet below the MVA. I thought maybe they would fly over VFR1 because at that time VFR1 was level at 027. I then saw VFR1 begin to climb so I told Aircraft X to turn 40 degrees left and called the traffic. Pilot complied and after one more traffic call; got VFR1 insight within 1 mile and several hundred feet altitude. Pilot said VFR1 was turning into him and asked to turn other direction. I said 'approved' Once they were clear I offered to climb the pilot back up and vector back out to the approach to start over but the pilot said they were ok and were ready to cancel IFR. I know I did several things against regulations here. 1. Never cancelled his approach clearance. -Never thought about it until after it was over. With VFR1 maneuvering around in unpredictable pattern; I just did what I felt I needed to do to prevent collision. Cancelling approach clearances is something hardly ever done in center environment; and the procedures for what to do just did not come naturally in the moment. 2. Turned below MVA - again; I just did what I thought I had to do. I would deal with the MVA once I felt the planes were separated.3. I just did not know what to do once the planes were clear. I knew Aircraft X was below the MVA and was not sure how to properly address the issue other than ask the pilot if they could get back on the localizer and land safely; or if they wanted to climb and start from the beginning.There is no way to prevent this from happening; but we need to review how to handle traffic alert situations below the MVA. It may have been covered; but in practicality we never see it.

Data retrieved from NASA's ASRS site 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.