What happened
On December 9, 2010, at Cincinnati/Northern Kentucky International Airport (CVG), a local control center (LCC) controller cleared Trans State Airlines Flight 8069, an Embraer E-145, to land on runway 18C. At the same time, Delta Air Lines Flight 2809, a Boeing 737-832 registered as N3731T, had been instructed to line up and wait on the same runway.
The controller had previously withheld takeoff clearance for the N3731T while monitoring a helicopter crossing the departure path at a low level four miles south of the airport. During this process, the controller momentarily lost sight of the helicopter on both visual and radar displays. After re-acquiring the helicopter and determining no conflict existed, the controller issued the takeoff clearance to the Boeing 737. However, this clearance failed to include required traffic information regarding the E-145 on approach.
As the E-145 approached within 0.5 nautical miles of the runway threshold, the crew queried the controller regarding a potential go-around due to the position of the Boeing 737. Simultaneously, the Airport Movement Area Safety System (AMASS) alerted the tower to the developing conflict. The controller subsequently instructed the E-145 to go around and climb to 4,000 feet. The E-145 passed to the right of the runway threshold and did not overfly the departing aircraft. There were no injuries and no fatalities.
The investigation
An investigation by the NTSB and FAA examined ATC data and on-site information. While the FAA initially identified the event as a significant operational error, the investigation concluded that a loss of separation did not occur. Investigators found that the E-145 offset its flight path during the missed approach, passing to the right of the landing threshold and the departing Boeing 737. Although the investigation determined the controller's performance did not comply with FAA Order 7110.65 and that the missed approach instructions could have been more definitive, assured separation was established before the E-145 crossed the threshold.