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Noise Abatement Procedures & Flight Patterns

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.

Noise Abatement Procedures for Jets - South Flow

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.

noise abatement procedures for south flow departures

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Noise Abatement Procedures for Jets - North Flow Daytime

North flow: daytime between 6:00 a.m. – 10:00 p.m.

North Flows Arrivals (red) and Departures (blue)

noise abatement procedures for jets departing during the dayArriving 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.

Noise Abatement Procedures for Jets - North Flow Nighttime

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)

noise abatement procedures for jets departing during the nighttime

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.

South Flow Operations Sample Flight Track Map

Winds from the south

When the winds are from the south, aircraft will depart the airport in a southerly direction and arriving aircraft will approach from the north. This operation occurs most commonly during the cooler, cloudier months of the year. The airport is in south-flow operations approximately 65 percent of the year.  

sample map of south flow flight operations at Sea-Tac Airport

 

North Flow Operations Sample Flight Track Map

Winds from the north 

When winds are from the north, aircraft will depart the airport in a northerly direction and arriving aircraft will approach from the south. This operation occurs most commonly during the warmer, sunnier periods of the year.

sample map of north flow flight operations at Sea-Tac Airport

 

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