Here's a detailed view of the Vashon Departure, a VFR procedure used at Boeing Field (KBFI) for traffic departing westbound when the airport is in a south flow--runways 14L and and 14R in use. The procedure is designed to avoid conflicts with airline traffic descending overhead into nearby KSEA. Most of the time, you will be directed to RWY 14R for takeoff, although when traffic is light ATC occasionally will assign 14L for departure.