Narrative:

I was working north; south sector combined as a tower radar; as well as controller in charge for the tower. There was a cessna doing survey work 7 to 9 miles off the departure end of the runway at 3;200 feet; coordinated with the local control. I turned aircraft X to a northwest heading and gave a descent to 2;500 feet as it was the MVA (minimum vectoring altitude) around the airport. My plan was to turn him to a 270 heading for his base turn to 1;300 feet before the MVA in front of him which was 2;800 feet. I used the shout line to talk to the adjacent approach to make sure they knew I had called traffic for aircraft Y who was VFR still in my airspace and didn't have the other VFR traffic in sight and was becoming more of a conflict than originally thought. I then was called by a departure that needed a turn as to not be a conflict with the survey cessna. As I finished my scan; I saw aircraft X was entering the MVA of 2;800 feet at 2;800 feet and still in his descent. I told aircraft X to maintain 3;000 [feet]. The pilot said they were below that; leveling off at 2;500 feet. I then told the aircraft to climb to 3;000 feet. The aircraft was never in danger of hitting the antenna that was at 1;800 feet. Having a supervisor in the operation may have helped the operation as it would have been an extra pair of eyes. Next time; I will descend to 3;000 feet in case my attention is brought elsewhere.

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Original NASA ASRS Text

Title: A Tower Controller working Approach from the Tower Radar became distracted and descended an aircraft below the Minimum Vectoring Altitude.

Narrative: I was working north; south sector combined as a Tower Radar; as well as Controller in Charge for the Tower. There was a Cessna doing survey work 7 to 9 miles off the departure end of the runway at 3;200 feet; coordinated with the Local Control. I turned Aircraft X to a northwest heading and gave a descent to 2;500 feet as it was the MVA (Minimum Vectoring Altitude) around the airport. My plan was to turn him to a 270 heading for his base turn to 1;300 feet before the MVA in front of him which was 2;800 feet. I used the shout line to talk to the adjacent Approach to make sure they knew I had called traffic for Aircraft Y who was VFR still in my airspace and didn't have the other VFR traffic in sight and was becoming more of a conflict than originally thought. I then was called by a Departure that needed a turn as to not be a conflict with the survey Cessna. As I finished my scan; I saw Aircraft X was entering the MVA of 2;800 feet at 2;800 feet and still in his descent. I told Aircraft X to maintain 3;000 [feet]. The pilot said they were below that; leveling off at 2;500 feet. I then told the aircraft to climb to 3;000 feet. The aircraft was never in danger of hitting the antenna that was at 1;800 feet. Having a Supervisor in the operation may have helped the operation as it would have been an extra pair of eyes. Next time; I will descend to 3;000 feet in case my attention is brought elsewhere.

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.