NTSB Identification: OPS12IA849
Incident occurred Tuesday, July 31, 2012 in Arlington, VA
Probable Cause Approval Date: 11/05/2012
Aircraft: , registration:
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
The airport had been using runway 1 for arrivals and departures all day. Because of thunderstorms south of the airport, the approach control area supervisor for Mount Vernon (MTV) attempted to coordinate with the airport tower supervisor to stop departures from runway 1 and temporarily land arrivals on runway 19, opposite to the traffic flow in use. According to the airport’s standard operating procedures, requests for runway changes must be approved by a tower supervisor, but the tower supervisor was unable to take the call because he was on a different phone line and distracted by administrative duties. Instead, a traffic management coordinator took the coordination call. A misunderstanding occurred between the MTV supervisor and the traffic management coordinator. The coordinator stated that she had missed the supervisor's reference to use of runway 19, and instead thought arrivals would be continuing to use runway 1, only with reduced spacing. The coordinator relayed the incorrect information to the local controllers responsible for the runways. The local controllers subsequently released two departures from runway 1 and both flights lost required separation with the first arriving airplane inbound from the northwest to land on runway 19.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: A hearback/readback error on the part of the tower traffic management coordinator, who did not understand the request being made by the approach control area supervisor and then communicated that misunderstanding to the local controllers. Contributing to the incident was the lack of standard coordination procedures between the tower and approach control for temporary runway changes and the accepted practice of operations supervisors being distracted by non-operational duties while responsible for tower operations and interfacility coordination. Full narrative available
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