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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 (green), and North Flow Departures Corridor (black)

A map titled “North Flow Nighttime Departure Corridor 22:00–05:59” showing aircraft flight paths over a coastal region with water and land areas. Several black airplane icons depict example aircraft positions. A green line marks the initial northbound departure corridor, labeled “Initial Departure Corridor,” with callouts reading “5 nm” and “8 nm and 4k feet.” A red line marks the southbound arrival corridor, labeled “Arrival Corridor,” with a “5 nm” callout near the bottom. A black line shows an alternate nighttime northbound departure routing extending west over the water. A compass rose indicating north, south, east, and west is in the lower right corner. The map is credited to Garmin (2018).

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.