Greener Skies Over Seattle Thanks to NextGen

Air Traffic Control, Alaska Airlines, NextGen, SEA - Seattle

It’s time for another post in my series talking about the benefits of NextGen air traffic control. Last time, we were in New York, but this time we’re heading across the country to Seattle where Alaska Airlines has been spearheading some major efforts to shorten flight times and reduce fuel burn thanks to new approaches in Seattle. I spoke with Sarah Dalton, Director of Airspace and Technology for Alaska along with Oscar Vela, a First Officer at Alaska who has been working on this project, to learn Seattle Airport New Approachmore.

The project is being called Greener Skies over Seattle, and I was first told about it when I visited the airline last September. The idea is to use RNP to enable a much quicker path into the airport. The picture on the right is a great one to show how this works for approaches from the South.

Today, aircraft coming from the south descend into Seattle using a traditional step-down descent. That means that airplanes are cleared to descend to certain altitudes. When they get there, they spool the engines up and level out until they are cleared to the next level below. Though this works well in practice, it is a waste of fuel since it requires constant increasing of thrust and then decreasing it again. There is now a new descent profile which will allow aircraft to come down smoothly and without interruption all the way down to 6,000 feet.

Once the aircraft gets to 6,000 feet, it is going to be about where the yellow and blue lines meet on the left side of the image (at least using this particular approach). It’s across the water from Sea-Tac Airport. Today, aircraft mostly have to continue on the blue line and then make a turn further up north before coming back around. The entire process is choreographed by the air traffic controllers with specific instructions on altitude and heading until the airplane is lined up with the runway. When the visibility is bad (which I assume is every single freakin’ day in Seattle), the aircraft will then use an ILS approach to come straight in for landing.

For those airlines that have RNP-equipped aircraft and trained crews, air traffic control now has the ability to give them an RNP approach. Instead of going further north, aircraft would engage at 6,000 feet and would automatically be guided around the curve and lined up for landing. This not only cuts off flight time and saves fuel, but it keeps a large swath of populated land north of the airport without airplane noise.

This sounds great, but why is NextGen necessary for this to work? Well, it’s the accuracy of the computer navigation that allows this to happen. Seattle has three parallel runways and often is landing on two runways at once. The FAA has a rule today in Seattle that if an airplane is coming into a turn on approach into the airport, there has to be at least 1,000 feet vertical or 3 miles horizontal separation. They can’t make that work so close to the airport so they have to send airplanes further north to get them lined up with cutting capacity at the airport.

The FAA and air traffic control are now trying out this new procedure, which began flight testing in June. It’s a big change for those who are used to controlling traffic, because they have to let go of some of that control. How are the tests going so far? Quite well. There have been 1,300 flights operated by Alaska under the test so far and there’s hope that this will be in place as a real procedure by spring of next year.

I asked if they had learned anything from the trials that required tweaking yet, and there was one thing. Since this is a much more precise approach, managing the speed on the airplane becomes much more important. So that’s something they need to make sure is hammered home with the pilots.

One of the criticisms brought up when I wrote about JetBlue at JFK in the last piece in this series was that some said it would rarely matter because runways weren’t usually in those configurations. That is not the case here.

The approach I mentioned is just one of the ones being tested. There are approaches that use this technology for landings to the north and to the south. It is used for traffic coming from the west, north, or south as well. The only traffic that can’t benefit from these approaches is that coming from the east. For Alaska, that means 75 percent of its traffic (and around 60 percent of Horizon’s traffic) can take advantage of this, and Alaska accounts for a huge chunk at the airport. All of the airplanes are equipped and the pilots are trained in those fleets, so there is significant benefit right off the bat.

But others with RNP capability can use this as well. It’s just one example of how landing procedures can be rethought with more accurate navigation. The result is less noise, less fuel burn, and shorter flight times.

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21 comments on “Greener Skies Over Seattle Thanks to NextGen

  1. SFO would benefit from this. Although airplanes from the south and east have plenty of space to descend over the bay, it may improve the 3-5 mile spacing between aircraft.

    Does RNP also allow horizontal separation of parallel landings to be reduced? This is an issue at both SFO and SEA with the parallel landings.

  2. Sigh, this is going to take away my spotting of planes on Capital Hill as they make the old approach.. But thats on the one day a month that we have clear skies, so its not that bad..

    1. You and me, both, Nick. I live on Capitol Hill as well and love watching the planes on approach to SEA. I will miss that, though I suspect house values might rise slightly with less noise.

    1. Alaska Airlines pioneered RNP technology in 1996 becoming the first airline in the world to use it. Alaska also was the first airline to be allowed to validate their own RNP approaches in 2009. Southwest didn’t get into the RNP game until 2010. Alaska was well ahead of anyone’s time.

  3. Brett, I’m sure you’re half kidding about Seattle’s weather, but it’s “not that bad.” (Yes, that’s the best I can do to argue against your statement that it’s bad “every freaking day.”) :-) From July to November, it’s actually pretty nice. Though it does suck just about “every freaking day” from December through February.
    Weather comments aside, I’m excited about the benefits of shorter flight times in SEA and throughout the US as this gets rolled out in more places.

    1. Steve, please don’t spill the beans.. We’ve already got enough population growth around here, so we’ve gotta keep the impression about rain around here. Get in line with the party line: Seattle Rainy Season: January 1 – December 31. Geez.

        1. Random fact – Atlanta actually gets more rain per year, on average, than Seattle. However, Atlanta tends to get more intermittent heavy downpours and thunderstorms, whereas Seattle tends to have more constant drizzles.

          1. gobluetwo, LIES! It rains in Seattle every day, all day long! We don’t even know what color the sun is, let alone if it is in the sky at the moment. :-p

            (Although, my first week on an internship in Atlanta it rained every day….)

    1. Probably because of the mountains to the east. It always seemed that flights from the east either fly north or south of Seattle, then turn to land.

      1. Ad a pilot for horizon, I can tell you that the article couldn’t be more accurate. I’ve flown both of the RNP procedures, both from the north and south. They are really cool, and super efficient.

        I’ve been cleared for the approach from somewhere south of Olympia before, and that was during the middle of the morning on a weekday. The reason for this is with published altitudes and speeds, ATC can easily predict your position in a four dimensions (time, people) to ensure it will fit with the traffic plan.

        At this time these procedures are not public, so only selec airlines are participating. These go far beyond the traditional RNP Approaches that southwest is doing; this is traffic management.

        The reason only those directions benefit for now is they have the most out of the way flight tracts, and the majority of flight from those directions are equipped for full RNP. Lots of older airplanes flown by the legacy carriers are not yet equipped. Due to FAA Rules on separations ( as previously mentioned), you can’t mix RnP operations with traditional ILS. At this time, all RNP is flown to the smallest runway, 16R/34L, during decent weather. When the weather drops, and boy does it ever, the airport reverts to traditional CATIII ILS operations.

        And he’s right. It rains all the freakin time ;)!

  4. Using adjunct navigation aids, including GPS and autopilot for more precise course-keeping is fine, but:
    A. It is not Next Gen and
    B. It is no safer or efficient for airport operations than typical VFR approaches, in the general case.

    The use of GPS navigation and a coordinated ADS-B network for en route ATC will allow more direct courses from airport to airport. But that also increases arrival headings and complicates runway use plans. The fuel “savings” at hubs like SEATAC are an illusion: the shortest city-hub-city route today is about 200 miles longer and includes an extra arrival and departure at the hub compared to a city-city flight.

  5. Greener skies just made a whole “new” bunch of folks angry actually enraged. Where they had no aircraft over their homes.. THEY DO NOW!! It’s lowered our real estate value. The southern approach overlays JBLM military base and how they let them do that is incredible. TALK ABOUT A SAFETY HAZARD!!. Collisions between military and commercial planes await!! I have seen JBLM aircraft bank turn hard to avoid the planes.You wonder why folks hate our government ..this is a classic example.. Alaska Airlines is a Bully in this region. Think average intelligent citizens don’t know it was done to save fuel. The Port of Seattle goes along with everything. They never say no to anything. “NO PUBLIC COMMENT’S OR OPEN HOUSES” on this change in our area. I am not talking about airport noise. I’m talking about impacts 45 MILES away to the South where we live. We live in Combat alley Roy, Wa. The FAA is a joke. They must have had nothing to do to come up with this abuse of landowners. Now the government wants all who fly to have an enhanced drivers license. There’s nowhere I need to fly anymore. It’s a dangerous world now. Amazing our legislative representatives didn’t even respond to greener skies. When an aircraft flies lower to the ground, like they are doing now, and it’s raining.. where does the jet exhaust go? ANSWER: INTO THE GROUND WATER AND LAKES AND STREAMS. Where’s the EPA? This isn’t green. IT’S MEANER SKIES TO US!!

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