LAX Implements Continuous Descent Approach

A nice side benefit of attending JetBlue’s press conference yesterday was that I had the opportunity to meet Ian Gregor, Communications Manager for the FAA’s Western-Pacific Region. We started talking shop, and soon enough I realized that there was something worth writing about here.

LAX has recently started using Continuous Descent Approaches (CDA) for some flights arriving from the East. What, that’s not exciting to you?

Ok, let me explain exactly what that means. Better yet, let’s go with an image here.

08_02_14 continuousdescent

Just about everyone is used to the stepped approach that has been the standard for some time (and I’ll guess nobody has experienced the drunken pilot approach). You know the feeling. The pilot reduces thrust, you start to descend, then he increases it and you start to flatten out. This goes on for quite some time until you end up on the ground. It’s like going down stairs, whereas the CDA is like going down a ramp. When the aircraft gets ready to descend, the pilot cuts power and the plane maintains a constant rate of descent all the way until touchdown.

That means no more powering up along the way and no more ear-busting changes in pitch of the aircraft. As you can imagine, that helps reduce noise (since the engines don’t spool up) and it helps reduce fuel usage. Good news for everyone, right? Why wouldn’t they have done this before?

Well, it’s not like there’s unlimited room to pull something like this off. You need to make sure that during your continuous descent, you don’t happen to get in the way of, oh, say, airplanes coming from Ontario or one of the other many airports in Southern California.

That’s why this can only be implemented for landings from the East. If you come from the North and West, you usually have to make that turn around downtown LA to come in. There just isn’t enough room to make this work out there. The good news, however, is that half of the arrivals at the airport come from the East. Although only half of those are using CDA right now, the other half will be soon enough.

This procedure was first tested in Louisville, and there was a “34 percent reduction in nitrogen oxide emissions below 3,000 feet, and a 30 percent reduction in aircraft noise within 15 miles of the airport. UPS aircraft flying this approach also save between 250 and 465 pounds of fuel per flight.” Sounds good to me. Maybe this will get some of those testy airport neighbors to stop whining so much.

They’re also rolling this out in other airports, so next time you come in for landing, see if you notice any difference.


21 Responses to LAX Implements Continuous Descent Approach

  1. Brian Lusk says:

    CF do they still land from the west at LAX during the “off” times at night? I would imagine that a CDA would work on that end of the pavement too, unless it would require flights from the east to detour too far out over the ocean.

    As a kid living in El Segundo during the first Watts riots, I could observe what my dad called “Saigon” approaches, which kept the flights at a higher altitude over Central LA, and then a steep approach into LAX.

  2. CF says:

    Yes they do. Those Hawai’i redeyes still come straight in from the West. I’m guessing they could do it, but that’s such a small percentage of flights into LAX that it’s probably not the highest priority. Right now, they only have plans to do this for arrivals from the East.

  3. Sheila says:

    Hi CF – Have you ever heard of a “slam dunk” approach? On a flight about 15 years ago, the pilot came on to say that we were going to have a “slam dunk” landing and not to be alarmed. If I remember correctly, it was a calm clear day, so I don’t know why we had to land like a basketball.

  4. CF says:

    Sheila – Yep, I’ve heard people refer to it before. Here’s a little page on the topic.

  5. Bryan in San Francisco says:

    Holy cow the web site you linked up to with the pilots’ forum is VERY scary to read. I wish I didn’t know about it.

  6. John M says:

    I really prefer the drunken option.

  7. Feldspar Goldstein says:

    UAL has been participing in a CDA test on redeyes from Hawai’i to SFO for quite some time.

  8. Cranky, what organization decides how approaches are designed at airports? (The FAA I assume?) And why are we now just figuring this out in 2008?

  9. CF says:

    Yep, FAA. I’m sure it’s not easy to get something like this implemented, so I’m just glad to see it happening now.

  10. Joe Canoy says:

    CF – Personally for me, CDA type of landing is less preferable than the Stepped Approach (the Drunk Pilots is obviously a joke) because it is a continous thrill and, I think, deprives passengers of the sufficient time to let out bubble in the ears. Gosh, I would miss that portions of the flight (when the flight is on flatten path) when I would hold my nose and blow, or press that area on my ears just below the entrance, then the sound around me start to become audible.

  11. Megan says:

    This is great news. Decreasing emissions/fuel burn and noise in one shot.

    I also heard that Delta was testing CDAs at ATL.

  12. lax says:

    The Continuous Descent Arrival has proven to be highly advantageous over conventional dive-and-drive arrival and approach procedures.
    From the environmental perspective, there are significant reductions in noise and emissions . From the economic viewpoint, there are significant fuel and flight time savings as well as the potential to meet or exceed current runway throughput without the need to vector aircraft.

  13. Richard says:

    The LAX CDA is almost worthless due to spacing requirements.. I watch the LA final on my radar at work, and at least 50 percent of them are vectored back-and-forth across the final to increase the spacing necessary to feed in aircraft approaching LA from the north. It’s funny to see the FAA (Gregor) tout the CDA, and watch it screwed up in practice. Nobody is saving fuel or money. Take that to the bank…

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  15. karl kettler says:

    CDA is re-inventing the wheel. It demonstrates how easily a new generation forgets or has ignored what came before. Airlines always conducted such approaches wherever and whenever they could. Just what does “establishing a CDA mean? It’s up to the pilot to chose what method of approach to use not an airport. All sorts of conditions impact the use of CDA that the pilot has to deal with. If an aiport imposes a CDA and aircraft arrive at a greater rate than what can be sequenced into a CDA it simply means that they burn more fuel orbiting in a holding pattern.until it’s their turn. Nothing is saved.

  16. FAA Test says:

    Very well written.This is great news.Decreasing emissions/fuel burn and noise in one shot.

    @ Sheila what is slam dunk approach?

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  18. sean says:

    what are the speeds of thes planes when they fly over my house in southeast LA i watch them all the time and wonder how fast they are going,the bigger one 747 and the like look like they are just flootting thank you in advance sean

    • CF says:

      It depends where you live exactly, but landing speeds are probably around 130 to 150 kts. Of course, that’s airspeed so if there’s a strong wind blowing, ground speed can be lower.

  19. H. Stewart says:

    Perhaps this is why those of us who live east of LAX now have hundreds of planes flying over our houses every day at much lower elevations??? Quieter for residents near the airport, but a nightmare for the rest of us.

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