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.

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21 Comments on "LAX Implements Continuous Descent Approach"

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Brian Lusk
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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.

Sheila
Guest

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.

Bryan in San Francisco
Guest
Bryan in San Francisco

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.

John M
Guest

I really prefer the drunken option.

Feldspar Goldstein
Guest

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

Nick Barnard
Member

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?

jojocanoysky
Member

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.

Megan
Guest

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

I also heard that Delta was testing CDAs at ATL.

lax
Guest

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.

Richard
Guest

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…

trackback

[…] That press release also mentioned that Air New Zealand has been participating in a special progam in San Francisco. Lo and behold, I just completely missed the press release. The airline is testing out a special kind of approach there. Basically, instead of the typical approach that is full of descending and leveling off, the aircraft starts descending at a gradual pace far away from the airport, without ATC directing them too much. I’m not sure if this is the same thing, but it seems quite similar to a program at LAX that Cranky describes […]

karl kettler
Guest
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… Read more »
FAA Test
Guest

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

@ Sheila what is slam dunk approach?

trackback

[…] that can be replaced by a gentle glide – allowing the use of minimal throttle. These CDAs (Continuous Descent Approaches) are being trialed at the UPS main hub in Louisville, Kentucky and are reckoned to save 40-70 […]

sean
Guest

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

H. Stewart
Guest

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.

trackback

[…] all without requiring new technology or spending hundreds of millions of dollars- which is why airports like LAX are beginning to experiment with […]

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