Fundamentals of airport flow: Why do we have so many arrivals over Vashon when SeaTac’s runway is North/South and we’re West of the airport? Statistics on Southflow vs. Northflow. Conventional RADAR STAR vs. the new NextGen ‘HAWKZ’ RNAV approach. What was the intended outcome of this change? What actually happened, especially in terms of altitude. Resources to learn more and studying real time flight paths and procedures. What have other communities done about this. Questions but first….the “Schultz Curve” i.e., everybody responds differently. Fundamentals of Airport Flow An airplane’s lift is a function of the airspeed, not the ground speed. By taking off and landing into the wind, ground speed is reduced. Outside special circumstances, for example Blue Angels practice, the flow of an airport flips according to the current and predicted wind direction. Source: Slide 11 from http://www.portseattle.org/ABOUT/COMMISSION/MEETINGS/2017/2017_04_25_RM_3c_supp_reduced.pdf Westside Downwind Arrivals Stats: Southflow vs. Northflow Southern winds and therefore Southflow are generally associated with cloudy/rainy weather and – unsurprisingly – predominate in the Puget Sound. Measured in “%of the time” in 2016: 73.8% Southflow and 26.2% Northflow Measured in operations 2016: 71.5% Southflow and 28.5% Northflow 195 days* completely Southflow, 128 mixed, and 43 completely Northflow. Vashon Daily Downwind Overflights Need to pick two days that are otherwise similar except one Southflow and the other Northflow. For example in 2016 two Thursdays: July 7th and July 14th. Southflow July 7th: 665 Total…Open full document
Notes
A given by David Goebel for (norpn.org)