Noise abatement flight procedures for jet aircraft are specific flight headings and altitudes designed to minimize noise over surrounding communities. The FAA, in cooperation with the SEA Airport and local communities, established the procedures to take advantage of existing geographical and compatible land use conditions wherever possible.
Although the FAA has sole authority over aircraft in flight, the SEA has taken the lead responsibility for monitoring and reporting air traffic activities in regard to noise abatement procedures. This information is used to track trends and identify problem areas. The FAA can direct aircraft to deviate from the noise abatement procedures for a variety of reasons, including weather, traffic safety, and aircraft performance. Propeller aircraft, being smaller and slower, cannot fly within the noise abatement corridors with jet aircraft and are allowed to deviate from the jet noise abatement flight procedures.
Whether an aircraft departs to the north (north flow) or the south (south flow) depends on wind conditions. Aircraft depart heading into the wind. In the Puget Sound region, winds tend to flow out of the south during cloudy, overcast days necessitating departures to the south. During clear weather, winds tend to flow out of the north, necessitating departures to the north.
South flow: 24 hours a day
South Flows Arrivals (red) and Departures (blue)
Arriving jet aircraft from the west fly north of West Seattle and then turn south to approach SEA Airport, preferably over Elliott Bay. From the east, arriving jet aircraft stay north of the 520 Bridge and then turn south to approach SEA Airport.
Departing jet aircraft are confined to a narrow corridor and can initiate a turn once they reach 5 nautical miles and at least 3,000 feet in altitude.
North flow: daytime between 6:00 a.m. – 10:00 p.m.
North Flows Arrivals (red) and Departures (blue)
Arriving jet aircraft execute final turns before entering the narrow 5 nautical mile (nm) corridor extending from the runways.
Departing jet aircraft are confined to a narrow corridor and can turn east once they reach 8 nautical miles and at least 4,000 feet in altitude. Jet aircraft turning to the west must continue north over the Duwamish industrial area before initiating their turns.
North flow: night time from 10:00 p.m. – 6:00 a.m.
North Flows Arrivals (red), North Flows Departures - Puget Sound Procedure (blue), and North Flow Departures Corridor (green)
Arriving jet aircraft execute final turns before entering the narrow five nautical mile (nm) corridor extending from the runways.
Departing jet aircraft are confined to a narrow corridor and should not turn to the east. Instead, all aircraft turn to the west and continue north over the Duwamish industrial area and Elliot Bay before initiating turns towards their final destinations.
Once through the North Flow Departures corridor, jet aircraft are then vectored toward their final destinations while over Puget Sound. Aircraft turning east must reach an altitude of at least 10,000 feet before re-crossing the shoreline.