TRACON controller reported they were distracted and did not hear their trainee assign an aircraft an...

Attributes
ACN	1672449
Time
Date	201908
Local Time Of Day	1801-2400
Place
Locale Reference	GSP.Airport
State Reference	SC
Aircraft 1
Make Model Name	Medium Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Light Transport
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Approach Instructor
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 4.0
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

I was training a developmental when he had a few arrivals into 2 different airports. Aircraft X was inbound from the north into gsp and there was another arrival from the west landing at a controlled satellite airport. The controller working the east sector also had 2 arrivals into the satellite airport. Originally aircraft X was given a decent to 5;000 and a 190 heading to keep him clear of the other controllers arrivals. The controller at the satellite airport called over on the shout line and was switching runways when one arrival was on a short final. After coordinating the runway change with the other east controller; the trainee went to descend aircraft X; but I told him to descend another satellite arrival. Since I was talking; I missed the altitude assignment and read back for aircraft X; but I incorrectly assumed the altitude assigned was 4;000. The trainee descended him to 3;000 in a 3;500 MVA with aircraft Y within 3 miles at 3;000 slowly descending into the satellite airport. I missed the altitude assignment because I was telling the trainee to do something else. I have no overreaching recommendations; but for myself I will not tell the trainee something while they are giving a control instruction.

Original NASA ASRS Text

Title: TRACON Controller reported they were distracted and did not hear their Trainee assign an aircraft an altitude below the Minimum Vectoring Altitude.

Narrative: I was training a developmental when he had a few arrivals into 2 different airports. Aircraft X was inbound from the North into GSP and there was another arrival from the West landing at a controlled satellite airport. The controller working the East sector also had 2 arrivals into the satellite airport. Originally Aircraft X was given a decent to 5;000 and a 190 heading to keep him clear of the other controllers arrivals. The controller at the satellite airport called over on the shout line and was switching runways when one arrival was on a short final. After coordinating the runway change with the other East controller; the trainee went to descend Aircraft X; but I told him to descend another satellite arrival. Since I was talking; I missed the altitude assignment and read back for Aircraft X; but I incorrectly assumed the altitude assigned was 4;000. The trainee descended him to 3;000 in a 3;500 MVA with Aircraft Y within 3 miles at 3;000 slowly descending into the satellite airport. I missed the altitude assignment because I was telling the trainee to do something else. I have no overreaching recommendations; but for myself I will not tell the trainee something while they are giving a control instruction.

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.

TRACON controller reported they were distracted and did not hear their trainee assign an aircraft an altitude below the minimum vectoring altitude.