Incident Overview
A near collision occurred between two airplanes operating in positive control airspace. The incident airplane had acknowledged and responded to a turn instruction that was issued to a third airplane with a similar call sign. As a result, the incident airplane turned to a heading that placed it and another airplane on an intersecting course.
Contributing Circumstances
The turn instruction was challenged by the airplane for which it was intended, but the incident airplane was not subsequently turned back to its original heading. The error was discovered shortly thereafter by the manual controller, who brought it to the attention of the radar controller. The radar controller then issued turn and climb instructions to the incident airplane, along with a traffic advisory.
Environmental Conditions
Visibility was reported by both flight crews as being reduced due to the presence of cirrus clouds, with no visible horizon.
Evasive Actions and Separation
Both airplanes took evasive action. Correlation of the two digital flight data recorder (DFDR) readouts with radar track data indicated that, at the point of closest approach, vertical separation was between 95 and 200 feet.