KSEA North Flow Arrivals: How Federal Way Residential Communities are Impacted

Here’s an example flight, showing how FAA/ATC chooses to accommodate airline profits ahead of citizen impacts. In this case, ATC controls a North Flow arrival from Alaska, to land on Runway 34L at SeaTac [KSEA]:

Assorted online images showing the arrival satview and data for Alaska Flight 914, Anchorage-Seattle, landing at 11:22AM on Friday, 7/14/2017. Notice how, as the arrival approached the south end of Vashon Island, ATC issued a left turn, which created low-altitude noise impacts on the north shore area of Federal Way / Dash Point. Notice also, the incredibly straight route for most of the flight; this shows, the ‘direct route’ efficiencies proclaimed as a key NextGen selling point in fact already exist! (source: FlightAware)

And, here’s a VFR sectional (aviation chart) that enables us to precisely identify distances ‘on final’, from the approach end of the runway at KSEA:

A screencap showing the ASA914 route superimposed on a VFR sectional. Note the gridlines on the VFR sectional; the tick-marks on the vertical gridlines are one statute mile apart. Red lines and tags have been added to this image, marking 5-mile, 10-mile, and 15-mile distances on a final to land Runway 34L. Contrary to Port of Seattle claims in the past, Runway 34L has become the primary landing runway at SeaTac, when in North Flow. (source: FlightAware)

The Problem:

Air traffic controllers (ATCs) generally do not factor environmental impacts into their control decisions. So, if an arrival lined up on the NextGen RNAV route over Vashon Island sees the airport on a clear day, if other traffic allows, ATC will be inclined to turn that arrival early, to line up onto a short final. In this example, that early turn happened because ATC saw enough space to safely issue the early turn, ahead of the next arrival. This arrival turned final near 279th. The consequences include an adverse impact upon thousands of homes, because early turns need to be much lower, to make the descent to the landing runway.

The Solution:

ATC needs to fully incorporate community concerns into their standard operating procedures.

For noise mitigation, and to protect residential communities, turns should be conducted no closer than to a 10-mile final. In this example, a turn to a 10-mile final (near Wild Waves) would occur over industrial/commercial properties at the Port of Tacoma, thus would potentially impact thousands fewer homes.

To the left, see an example of a later flight that was kept higher and, turned onto final at a distance of approximately 14-miles: Xiamen Air Flight #845, a Boeing 788, from Shenzhen, China (near Hong Kong).