Why is it getting so much worse? (NextGen For Dummies)

You might call the current situation for residents in certain neighborhoods around Sea-Tac Airport a ‘Perfect Storm’.

What’s The Frequency, Kenneth?

First, there is the fact that in 2012 Delta Airlines made Sea-Tac their main hub along with Alaska Air. So that made Sea-Tac home base forput two very large airlines. And starting in 2012, the daily operations count definitely did jump.

Then there is the fact that King County has been experiencing an economic boom; not just with Amazon and ‘tech’ companies and passenger travel, but also with exports. The State Of Washington is the third largest exporter of goods in the United States and Sea-Tac Airport has been a big part of that success.

Those two factors (more airlines, regional growth and increased exports) have increased the frequency of daily operations from around 850 a day in 2009 to 1250 a day in 2019. A whopping 47% increase.

But the increased number of flights is not the main reason you feel like the current situation is intolerable. There two other reasons, which have to do with concentration, ie. where the flights are taking off and landing. One type of concentration is easy to understand, the other a bit more complicated. Neither will make you happy.

The Big Lie

The first big change in ‘concentration’ is in the geographic distribution of flights. But to explain that, we need a bit of history.

Too Close

Some history: one reason the Third Runway was deemed so necessary in the 90’s was that the second runway was built a bit too close to the first runway. Really. There are various FAA safety rules that limit take-offs and landings when two runways are so close together. If one looks at the operations totals before the Third Runway was built, Sea-Tac was actually running almost as many operations in 1999 as they are in 2019! Even then they knew how to jam a lot of flights onto those two runways. If the first two runways had been built further apart (or is it farther? :D) one could argue that, with today’s technology, a third runway would not have been necessary.

Anyhoo, when the Third Runway came on-line, the fact that it was farther away from the First Runway allowed for a much greater degree of flexibility in scheduling take-offs and landings. No longer did Air Traffic Controllers on one runway have to worry about what was going on at the other runway.

Now everyone in the area remembers The Big Lie, “We will only use the Third Runway for bad weather or in ‘overflow’ or emergency situations.” In addition to being a promise they were not legally able to make (see our article on ANCA), the people who signed that document knew full well that the Third Runway was too damned convenient to not use all the time. It’s irresistible.

So the Third Runway has had the net effect of helping to concentrate flights on either the First Runway (for 2/3rds of take-offs) and the Third Runway (for 2/3rds of landings).

Some outcomes

Many of the people who complain most about ‘the airport’ are really complaining that so many flights moved from the east side of the airport to a new location west along Puget Sound: right over their houses under the Third Runway.

(It’s no coincidence that the majority of current activists (including almost all of the Quiet Skies people) live under the Third Runway.)

Comparatively few people under the First Runway (east) complain, even though they continue to have just as much noise. Perhaps this is because they’ve had so many years as ‘boiled frogs’–they’ve simply had more decades to become acclimated to the pounding.

And ironically, some people who live under the Second (middle) Runway are the big (cough) ‘winners’ in all this. Beyond a mile from the runway, they now experience less noise than before!

NextGen For Dummies

Beyond the choice of runway, the other type of concentration has to do with changes to the flight paths leaving from and arriving to those runways. These changes falls under the FAA branding NextGen.

NextGen isn’t one thing. It’s actually a blanket term covering a whole suite of different technologies including computer-control and GPS which is referred to as Performance Based Navigation (PBN). Working together they  concentrate the flight paths to as narrow a track as possible (ie. a straight line) on take-off and approach. This makes the rest of the area a LOT quieter for everyone not under the flight path. A lot of neighborhoods only a few blocks away to the left or right of a flight path will be noticeably quieter. The majority of people not directly under the flight path really do benefit from less airplane noise. But NextGen makes life a LOT worse for everyone who is directly under the flight path.

Another great ‘benefit’ of NextGen is that the technology allows the airlines to land planes a lot closer together (as little as forty five seconds apart) using another series of technologies, the best known being something called Wake Recategorization (Wake Recat) Contrast this with the standard three minutes apart from ten years ago. What this does is create a constant ‘wash’ of sound.

Follow The Money

One of the most common demands from residents is along the lines of “Why can’t you simply take-off and land along big highways and try to avoid neighborhoods?” Well, a straight-line take-off and landing also saves a ton of fuel and that saves the airlines millions of dollars every year. In other words, the current NextGen model is efficient. And as we’ve said so many times, the two watchwords of all FAA policy are “Safety and efficiency”. Meaning ‘safety of passengers and efficiency for the airlines’. Changing routes is slightly less efficient and that means that, under Federal Law (keep referring back to ANCA, it truly is the root of all evil) the airlines have no legal duty to alter their routes to make residents happier. Not to mention the fact that they have no financial incentive to do so either.

Yes, but the planes are so much quieter

Before winding up, we need to address one objection you’ll still hear from people, usually older residents and members of the aerospace industry. “The planes are so much quieter now, quit whining!” Which is to say that the design of more recent aircraft like the Boeing 777 really are a lot quieter than older Stage 3 planes like the 747. And if one does live in a neighborhood with relatively few flights, this change in fleet mix can be a dramatic improvement in the daily average noise calculations the FAA uses when monitoring a neighborhood.

But for people directly under the flight path, this is a canard because the sheer number of flights and their concentration now overwhelms any improvements to aircraft design.

The reason has to do with the messy business of how human’s perceive noise. When a plane goes overhead, we perceive the sound with a certain amount of ‘annoyance’. The sound of a typical modern airplane flying overhead is perceptible for around two minutes; it approaches quietly, gets increasingly loud, then gets increasingly quiet as it moves away from your position. That’s two minutes. During that time, your body experiences a certain level of instinctive and automatic stress in response to a very loud noise. (Think the approach of hoof-beats from horses or a thunder storm.) Over time, you learn that the airplanes are a normal part of life and the body (sort of) adapts. But in order for your body to adapt, there needs to be a period of ‘rest’ between flights which allows your nervous system to recover. In the past, flights might go over a typical home once every 3-5 minutes at peak hours.

However, with the current flight paths and traffic levels, residents under the flight paths now routinely experience a flyover once every 45 seconds. And that means that while the last flight is still quite loud, the next flight is approaching which creates an additive level of noise and prevents the body from having that critical rest period to recover from the loud noise. In short: during peak periods, there is no rest. The planes are one loud wash oft noise at an average level that is beyond a safe level in terms of long-term health.

The failure of the current laws to account for this lack of rest between flights is what creates the greatest long-term damage to human health. There is simply no way to mitigate against it other than by reducing the exposure to these very loud sounds.

What we think: Redefining Capacity

As with so many airport issues, the Federal and State laws are unambiguous. ANCA is written specifically to optimize ‘efficiency’ and ignore the effects on residents under flight paths.

But beyond the legal issues, changing routes is the ultimate ‘not in my back yard’ issue. People who previously had ‘quiet skies’ deeply resent now having to experience the pain that people under the old flight paths seem to have gotten used to. When daily operations reach a certain level there is really no way to ‘spread the pain’ without creating conflict between residents in various neighborhoods. So it’s the ultimate NIMBY issue. Everyone wants the planes to go ‘somewhere else’.

We believe that when an airport reaches that level of traffic; ie. where there can be no reasonable distribution of flight paths without creating intense local conflict, the airport has, by definition, reached its capacity.

In other words, our first goal should be to insist that the FAA definition of an airport’s essential ‘capacity’ be altered to include its effects on the surrounding neighborhoods.

The various ‘mitigations’ that have been proposed (and to a small extent implemented) over the years have not been able to keep up with the rapid increase in flights. Sound insulation programs and filtration systems are band-aid solutions at best and focusing our efforts on more band-aids creates a tacit acceptance that neighborhoods under flight paths will never be afforded anything approaching a healthy living environment.

As politically ‘impossible’ as it may seem, the only long-term solution is to advocate for an absolute cap on the number of flights that any airport can accommodate.

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