Narrative:

I was assigned to split off jelo; which is a position that is rarely split off from west departure. The controller in charge and front line manager (flm) said that I could just plug in and help if it was too busy to split it. I got there and observed that west departure was busy; but handling it. I sat down and set up my scope and scanned the traffic. I saw that there was an aircraft for eik; an aircraft on final (aircraft Y). I took a call from bjc tower saying that 'aircraft X needs to return to the airport'. I looked and saw aircraft Y and assumed that's who they were talking about; though he was on final. I told bjc tower to use the jelo frequency. I told the west departure controller this and he said? 'You're keeping him? Alright.' I asked about the bjc releases and he gave me the strip of the release; then the proposal strips. At some point he said 'you got it' and I was surprised; because I hadn't been able to call for a briefing.I asked aircraft Y what he needed; and aircraft X said he needed vectors to the ILS at bjc. I was looking at aircraft Y on final. I think I asked him if he needed to be boxed around; but I'm not sure. I issued a left turn to 170. Aircraft X asked about what altitude to maintain. Thinking I was talking to aircraft Y; I told him 7;000.I called bjc tower thinking that aircraft Y was just taking his time starting his turn; letting them know that he would enter their airspace. The bjc controller questioned me; saying that 'we have this departure coming out'. Thinking that the only problem was aircraft Y; I said it wouldn't matter. Then I saw aircraft X just north of bjc. I figured out later; after I saw the strip; that he was coming from bdu. He was beneath the MVA and very close to the bjc departure that had just tagged up. I issued a vector to the west and a climb to 8;000. Once they passed I issued a vector to the southeast.at some point in this west departure flashed aircraft X to me.I should have insisted on a recorded briefing. I got wrapped up in thinking that the other controller was down the tubes and needed help immediately. This shortcut caused me to miss a vital piece of the picture. I also could have listened to the call signs more carefully.I'm not sure if I made the mental shortcut of saying 'aircraft X' and thinking I'm talking to aircraft Y. I'll be very vigilant about that kind of thing.

Google
 

Original NASA ASRS Text

Title: A D01 TRACON Controller misidentified aircraft with similar sounding call signs and issued a descent and heading to an aircraft below the Minimum Vectoring Altitude and into confliction with departing traffic.

Narrative: I was assigned to split off JeLo; which is a position that is rarely split off from west departure. The CIC and Front Line Manager (FLM) said that I could just plug in and help if it was too busy to split it. I got there and observed that west departure was busy; but handling it. I sat down and set up my scope and scanned the traffic. I saw that there was an aircraft for EIK; an aircraft on final (Aircraft Y). I took a call from BJC Tower saying that 'Aircraft X needs to return to the airport'. I looked and saw Aircraft Y and assumed that's who they were talking about; though he was on final. I told BJC Tower to use the JeLo frequency. I told the west departure controller this and he said? 'You're keeping him? Alright.' I asked about the BJC releases and he gave me the strip of the release; then the proposal strips. At some point he said 'you got it' and I was surprised; because I hadn't been able to call for a briefing.I asked Aircraft Y what he needed; and Aircraft X said he needed vectors to the ILS at BJC. I was looking at Aircraft Y on final. I think I asked him if he needed to be boxed around; but I'm not sure. I issued a left turn to 170. Aircraft X asked about what altitude to maintain. Thinking I was talking to Aircraft Y; I told him 7;000.I called BJC Tower thinking that Aircraft Y was just taking his time starting his turn; letting them know that he would enter their airspace. The BJC Controller questioned me; saying that 'we have this departure coming out'. Thinking that the only problem was Aircraft Y; I said it wouldn't matter. Then I saw Aircraft X just north of BJC. I figured out later; after I saw the strip; that he was coming from BDU. He was beneath the MVA and very close to the BJC departure that had just tagged up. I issued a vector to the west and a climb to 8;000. Once they passed I issued a vector to the southeast.At some point in this west departure flashed Aircraft X to me.I should have insisted on a recorded briefing. I got wrapped up in thinking that the other controller was down the tubes and needed help immediately. This shortcut caused me to miss a vital piece of the picture. I also could have listened to the call signs more carefully.I'm not sure if I made the mental shortcut of saying 'Aircraft X' and thinking I'm talking to Aircraft Y. I'll be very vigilant about that kind of thing.

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.