Runway Use Plan

The Federal Aviation Administration (FAA) has the responsibility for managing air traffic, and, at any time they have the right to change the way they use the runways to efficiently manage air traffic. The following is a runway use plan that best serves typical operations at Sea-Tac Airport under normal conditions:

South Flow Runway Use Plan

Regular overnight usage. During regular overnight operations in normal weather patterns when arrival demand decreases, the FAA plans to greatly reduce its use of the third runway (16R).
South flow arrivals and departures during good weather. During normal weather patterns, and periods of low demand, the primary south flow arrival runway is the center runway (16C). The easternmost runway (16L) will be the primary south flow departure runway. When airport demand increases, both 16R and 16L will be used for arrivals and 16C will be used as the primary departure runway.
South flow arrivals in lower visibility conditions. During periods of low demand the primary south flow arrival runway is 16C. Runway 16L will be the primary south flow departure runway. When airport demand increases, in order to have two streams of arriving traffic that can maintain appropriate separation during lower visibility conditions, runways 16R and 16L will be used for arrivals. Runway 16C will be the primary departure runway.
South flow departure demand. Runway 16R will also help with airfield efficiency when there is an increased departure demand. The FAA can increase use of 16R for arrivals in order to allow departures off of both runways 16L and 16C.

North Flow Runway Use Plan

Regular overnight usage. During regular overnight operations in normal weather patterns when arrival demand decreases, the FAA plans to greatly reduce its use of the third runway (34L).
North flow arrivals and departures during good weather. During normal weather patterns, and periods of low demand, the primary north flow arrival runway is the center runway (34C). The easternmost runway (34R) will be the primary north flow departure runway. When airport demand increases, both 34R and 34L will be used for arrivals and 34C will be used as the primary departure runway.
North flow arrivals in lower visibility conditions. During periods of low demand the primary north flow arrival runway is 34C. Runway 34R will be the primary north flow departure runway. When airport demand increases, in order to have two streams of arriving traffic that can maintain appropriate separation during lower visibility conditions, runways 34R and 34L will be used for arrivals. Runway 34C will be the primary departure runway.
North flow departure demand. Runway 34L will also help with airfield efficiency when there is an increased departure demand. The FAA can increase use of 34L for arrivals in order to allow departures off of both runways 34R and 34C.