This first blog post will summarize key information on how “NextGen” in general, and RNP in specific, has impacted the rural community of Vashon Island near Seattle. Vashon is accessible only by ferry and as such attracts many people seeking a quiet and peaceful rural/forest environment. The ferry-only access can certainly be a hardship, but again people willingly make that trade off for, at least before mid-2015, a quiet and peaceful environment.
Fundamentals:
The most important fundamental concept regarding flight tracks is that airports almost always operate in a flow determined by the current and forecast wind direction. A plane’s lift is a function of airspeed, not ground speed, so all arrivals and departures want to land and take off into the wind so that the required ground speed is minimized, which increases safety. In the Seattle area, Southern winds predominate and so KSEA (Seattle-Tacoma International Airport) operates in “Southflow” most of the time (65% to 80% depending on the year and how you measure it). This means that any flight arriving from a location South of Seattle (which most are), must first fly North of the airport, then turn South and prepare to land. This segment of arrival, when planes are actually flying away from the airport, is called a “downwind leg”. For Vashon Island which is West, not North or South of the airport, this downwind leg is the source of the RNP misery.
The Change:
For nearly 70 years flights were randomly vectored on approach to KSEA. This created a pattern where flights, and their plane noise, was broadly dispersed over the entire region, except on final approach when planes must be lined up with the runway. In the 90s this was modified to include the idea of ” four posts” when nearing the Puget Sound area that flights would be directed to, but they were still randomly vectored after that, achieving a broad dispersion of plane noise.
In 2012 the FAA and the Port of Seattle pursued the oxymoronically named “Greener Skies Over Seattle” project. The entire 892 page report can be downloaded near the bottom of: https://www.faa.gov/air_traffic/environmental_issues/ared_documentation . Of note is that there was zero community outreach on Vashon Island when this radical change was being planned, arguably the community most negatively impacted by the change. While the NextGen procedure is only partially implemented North of Vashon, the razor sharp flight paths and the lowered altitudes over Vashon were implemented in mid-2015.
The net result of this partial implementation is that flights get low early and then fly low and levels for tens of miles due to the realities of traffic forcing the downwind legs further and further North. In the past the decent profile below 10,000 feet was more optimized so that arrivals could be kept higher until it was known how long their downwind leg would be. Now they are brought low assuming their downwind leg will be short, when in reality it usually isn’t. NextGen has reduced level-offs above 10,000 feet (where nobody can hear them), but it did this by effectively moving them to 3000 or 4000 feet instead over large areas of the Puget Sound. This extended low and level flying is extremely fuel inefficient and I strongly suspect that an analysis of “Greener” Skies as implemented would reveal that it has increased fuel waste and green house gas emissions. The FAA has spent many billions of your tax dollars working on NextGen and in the end it has (very likely) resulted in more wasted fuel and greenhouse emissions and has definitely devastated the mental and physical health of many of the ground. As with other federal government programs which need to find some way to spend the billions of dollars appropriated to them, it has acquired a life of its own and whether or not it works, or indeed achieves the opposite of its stated goals, becomes irrelevant. The program continues regardless of the damage it causes.
On April 25 2017 the Port of Seattle held a regular commission meeting on the subject of NextGen. The agenda is here http://meetings.portseattle.org/portmeetings/attachments/2017/2017_04_25_RM_agenda_linked.pdf and the video can be streamed here https://meetings.portseattle.org/index.php?option=com_meetings&view=meeting&Itemid=358&id=1686&active=play. The FAA slides completely distorted and/or outright falsified reality, but there was an interesting slide on the Port’s deck:
This does not show the true severity of the situation, as the ‘after’ line on the right should really be a single pixel wide and it doesn’t show the elevation being lowered several thousand feet at the same time. However it is the closest thing to honesty I have yet seen from the FAA or the Port.
More information coming.