Incident Overview
During a runway configuration change at a major airport, operations were transitioning from arrivals and departures on Runways 32L and 32R to departures from Runway 32R and arrivals to Runway 32L. Simmons Flight 4321, an ATR-42, was cleared for takeoff from Runway 32R by the North Local Controller (NLC) and subsequently instructed to turn left to a heading of 270 degrees. Meanwhile, the South Local Controller (SLC) cleared United Flight 1206, a DC-10, for takeoff from Runway 32L.
Sequence of Events
As United 1206 became airborne, Simmons 4321 had already initiated its left turn, which placed the ATR-42 in the departure path of the DC-10. This resulted in a loss of separation, with zero feet vertical separation and 0.5 nautical miles lateral separation.
Controller Communication
The NLC stated that he had a discussion with the area supervisor regarding departure headings, specifically whether there were no departures on Runway 32L. In that conversation, the NLC believed the area controller indicated that a left turn would be acceptable. However, the area supervisor denied discussing a left turn; his recollection was that they discussed using a 340-degree heading versus a 350-degree heading to protect for missed approaches.