Near Collision Involving Alaska Airlines Flight 601 and a Mooney M20C (N954AS)

Incident Overview and Aircraft Involved Alaska Airlines Flight 601, operating as ASA601 with registration N954AS, was executing a standard instrument departure when it came into close proximity with a Mooney M20C, registration N91Y. The Mooney was transiting Reno airspace at 12,500 feet MSL. ## Controller Actions and Communication Gaps The local controller did not instruct ASA601 to contact departure control after takeoff. During the initial climb, the departure controller and area manager left their position to answer a phone call from a facility technician regarding TRACON business. Simultaneously, the arrival controller was instructing the Mooney pilot to change transponder codes in preparation for a handoff to Center. ## Contributing Factors The arrival controller reported that he did not see the data block for ASA601 because his attention was diverted to the Mooney. There was some confusion between the Mooney pilot and the controller regarding the transponder code. The changing of the transponder code and the Mooney's intermittent Mode C transponder prevented ASA601's TCAS system from acquiring the Mooney. ## Aftermath After returning from the phone call, the departure controller attempted to call ASA601 but was unsuccessful. He then contacted the local controller, who informed him of the near collision.