For the purposes of this proposal, the Green sector is N-APP, the Orange is S-APP and the Blue is E-APP. Overlapping colors/sectors are explained below.

The area around BFI RWY 31 and extending out to the S-APP airspace will be the property of S-App for BFI arrivals/departures.

Goals:

• Create a simple 2 & 3 way split for approach.
• Aircraft departing or arriving SEA/BFI should never contact more than 2 of the 3 approach sectors.
• No single sector should have more than 2 approach corridors.
• Where crossing corridors exist, they should not exist on sector boundaries.
• Provide enough space for control area handling final approach areas to BFI/SEA to sequence and turn aircraft to final.

South Flow

Split 3 ways

• N-App controls JAWBN, GLASR, north arrivals, and turns to final.
• S-App handles SEA Departures and BFI departures under pointout with E-App. S-App also controls descents of OLM and CHINS arrivals.
• E-App handles EPH arrivals, BLUIT and northbound departures.

Split 2 ways

• N-App maintains the same airspace as before
• S-App now controls the E-App area

Notes

S-App may handle ELMAA deps on pointout with N-App. S-App will also handle TCM/TIW deps/arrivals. (TIW on pointout for long finals).

North Flow

Split 3 ways

• N-App handles JAWBN/N arrivals and the west/north/south deps.
• E-App separates east deps from east arrival streams
• S-App handles final approach and south arrivals. Separates SUMMA deps from arrivals.

Split 2 Ways

• N-App controls same area
• S-App controls E-App area

Notes

• Area shown north of SEA in dashed lines belongs to N-App but is overlapping with E-App. When an aircraft is cleared from SEA, they'll be told in their clearance what frequency to contact departure on depending on direction of flight. Those departing to the east or SUMMA would contact E-App, the rest to N-App.